New Transonically Stable 308 Bullet

[Buffalobob]

Berger has designed and tested a new 308 bullet that will pass through the transonic zone without being upset. It is not yet listed on their website but is in the production line. Bryan Litz, the ballistician for Berger has loaded ammo listed for sale on his website. It may have some interesting applications for the military in terms of extending the range of the 308 sniper rifles.

Here is the link

http://www.appliedballisticsllc.com/TacticalAmmo.html

[Sinister]

Interesting. Nowhere in that page do they indicate what their muzzle velocity is out of the 20-inch OBR.

[Buffalobob]

You should duly note that it is not ammo loaded by Berger. It is loaded by Bryan who keeps his personal company even while an employee of Berger.

I would suspect it is not loaded to any extreme velocity for insurance liability reasons. I would imagine out of a 20 inch barrel you could get 2500 to 2550 fps depending on lots of factors.

[mojaveman]

Does barrel length and rifling have much affect on transonically stabilizing a bullet? I have a friend who builds custom tactical rifles and he made one with a barrel that was about three feet long. He was trying to explain it all to me but I was in a hurry that day and I didn't quite get all of it. Just curious.

[mojaveman]

Some tests done a few years ago found that there is very little to no velocity loss out of a 20 in barrel for a .308 depending on the powder. Here is a link to an article I found using my google-fu

http://www.tacticaloperations.com/SWATbarrel/

And and except from the article.

That would equate to about 4FPS for each inch of barrel length lost.

[Buffalobob]

Does barrel length and rifling have much affect on transonically stabilizing a bullet? I have a friend who builds custom tactical rifles and he made one with a barrel that was about three feet long. He was trying to explain it all to me but I was in a hurry that day and I didn't quite get all of it. Just curious.

Most serious 1K competitors using the 308 will use a 28-30 inch barrel. They will hand load their own ammunition and will push pressures as high as they can without affecting group size. The idea is to achieve high velocity to minimize wind drift and drop variations and to stay above Mach 1.2.

Barrel twist is not especially important to transonic stability above and beyond regular stability concerns. Bullet shape is important. Shallow boat tail angle and no meplat or very small meplat, and short bearing surface seem to be important. Interestingly, the old black powder buffalo sharps aficionados shoot cast lead bullets very accurately far beyond the transonic zone.

As far as the Swat study I have not shot any factory loaded rifle ammo in three decades so I just don't have any knowledge base concerning burning rates of the powder used.

[Buffalobob]

The 308 is no longer used by serious 1000 yard shooters these days.

I assume from your statement that you have never actually done any competition shooting at long range. There is a whole group of F-class called F-T/R which includes only 308 and 223 (military calibers ). It is what I shoot and what I trained my children to shoot. I have posted several videos of my children shooting in long range F-class with a Rem 40X in 308. The 6.5-284 competes in a class called "open" which is not head to head with the 308.

Do you actually know anything about bullets and the transonic zone and killing people?

[incarcerated]

Bullet shape is important. Shallow boat tail angle and no meplat or very small meplat, and short bearing surface seem to be important.

Ahhhh…
I can see the meplat being an issue, as a hollow point degrades the BC of any rifle bullet, but I had not considered the boat tail. If the instability derives from changes in the bullet’s shockwave as it crosses the transonic plane, which was my uneducated guess (and which turns out to be not quite accurate), my attention would be on the front of the bullet. Being a short-range shooter (nothing much past 200) and fond of flat base bullets, I would not have considered the effect of the vortex following the bullet. The short bearing surface will help at both ends of the bullet, or put differently, will result from reducing bluntness up front and lengthening the taper of the boat tail.
Will an epoxy filled nose and a rearward center of gravity help things here?
And where is Longrange1947? I’d like to hear his input on this.

A little Google-fu helped throw some light on the issue for me: rather than looking at the bullet, it got me looking at aerodynamics, specifically, the transonic zone:

http://answers.yahoo.com/question/index?qid=20100713211733AA9JEeY
The Transonic zone is a condition of speed when some parts of the air flowing over an object, such as an airfoil are supersonic already and some parts are not. The term to watch between the transonic zone and the supersonic zone is called the Critical Mach number...where the airlow in some parts of an object, again, the typical example would be an airfoil..reaches the speed of sound, even though other parts of the aircraft has not crashed through the sound barrier. When this condition is reached, it will create a weak shock wave.

A shock wave is a condition where a there is always a rapid rise in pressure, density and temperature. As the aircraft approaches the transonic zone--Mach .80 to Mach 1.2--the pressure waves do not have time to move out of the way of the oncoming aircraft since it is traveling along with them. The waves compress and the air becomes far more dense. When the plane meets the compacted air, it hits with a jolt and a series of shock waves builds up perpendicular to the direction of flight. The first shock wave attaches itself to the center of the wing's upper surface as the airflow there reaches Mach 1, As the plane's speed increases, the air under the wing also reaches mach 1 and a second shock wave forms....

http://www.centennialofflight.gov/essay/Theories_of_Flight/Transonic_Flow/TH19.htm
An airplane flying well below the speed of sound creates a disturbance in the air and sends out pressure pulses in all directions. Air ahead of the airplane receives these "messages" before the airplane arrives and the flow separates around the airplane. But as the plane approaches the speed of sound, the pressure pulses merge closer and closer together in front of the airplane and little time elapses between the time the air gets a warning of the plane's approach and the plane's actual arrival time. At the speed of sound, the pressure pulses move at the same speed as the plane. They merge ahead of the airplane into a "shock wave" that is an almost instantaneous line of change in pressure, temperature, and density. The air has no warning of the approach of the airplane and abruptly passes through the shock system. There is a tendency for the air to break away from the airplane and not flow smoothly about it; as a result, there is a change in the aerodynamic forces from those experienced at low incompressible flow speeds….
At subsonic speeds, drag was composed of three main components—skin-friction drag, pressure drag, and induced drag (or drag due to lift). At transonic and supersonic speeds, there is a substantial increase in the total drag of the airplane due to fundamental changes in the pressure distribution.
This drag increase encountered at these high speeds is called wave drag. The drag of the airplane wing, or for that matter, any part of the airplane rises sharply, and large increases in thrust are necessary to obtain further increases in speed. This wave drag is due to the unstable formation of shock waves that transforms a considerable part of the available propulsive energy into heat, and to the induced separation of the flow from the airplane surfaces. Throughout the transonic range, the drag coefficient of the airplane is greater than in the supersonic range because of the erratic shock formation and general flow instabilities. Once a supersonic flow has been established, however, the flow stabilizes and the drag coefficient is reduced…

It is a large loss in propulsive energy due to the formation of shocks that causes wave drag. Up to a free-stream Mach number of about 0.7 to 0.8, compressibility effects have only minor effects on the flow pattern and drag. The flow is subsonic everywhere. As the flow must speed up as it proceeds about the airfoil, the local Mach number at the airfoil surface will be higher than the free-stream Mach number. There eventually occurs a free-stream Mach number called the critical Mach number at which a supersonic point appears somewhere on the airfoil surface, usually near the point of maximum thickness, and indicates that the flow at that point has reached Mach 1. As the free-stream Mach number is increased beyond the critical Mach number and approaches Mach 1, larger and larger regions of supersonic flow appear on the airfoil surface. In order for this supersonic flow to return to subsonic flow, it must pass through a shock (pressure discontinuity). This loss of velocity is accompanied by an increase in temperature, that is, a production of heat. This heat represents an expenditure of propulsive energy that may be presented as wave drag. These shocks appear anywhere on the airplane (wing, fuselage, engine nacelles, etc.) where, due to curvature and thickness, the localized Mach number exceeds 1.0 and the airflow must decelerate below the speed of sound. For transonic flow, the wave drag increase is greater than would be estimated from a loss of energy through the shock. In fact, the shock wave interacts with the boundary layer so that a separation of the boundary layer occurs immediately behind the shock. This condition accounts for a large increase in drag that is known as shock-induced (boundary-layer) separation….

At a free-stream Mach number greater than 1, a bow shock appears around the airfoil nose. Most of the airfoil is in supersonic flow. The flow begins to realign itself parallel to the body surface and stabilize, and the shock-induced separation is reduced.
This condition results in lower drag coefficients. Supersonic flow is better behaved than transonic flow and there are adequate theories that can predict the aerodynamic forces and moments present. Often, in transonic flow, the flow is unsteady, and the shock waves on the body surface may jump back and forth along the surface, thus disrupting and separating the flow over the wing surface. This sends pulsing, unsteady flow back to the tail surfaces of the airplane. The result is that the pilot feels a buffeting and vibration of both wing and tail controls. This condition occurred especially in the first airplane types to probe the sound barrier....

[WRMETTLER]

This is an interesting subject.

Bryan Litz is engaged in a thread about this subject here:

http://www.usrifleteams.com/lrforum/index.php?showtopic=13415&st=75

It seems that there are many different issues relating to the stability of a bullet as it passes through the transonic zone and merely by passing through the transonic zone a bullet does not necessarily become either unstable or inaccurate.

[Ramirez]

You should duly note that it is not ammo loaded by Berger. It is loaded by Bryan who keeps his personal company even while an employee of Berger.

I would suspect it is not loaded to any extreme velocity for insurance liability reasons. I would imagine out of a 20 inch barrel you could get 2500 to 2550 fps depending on lots of factors.

edit: I'm speaking about 168g

I have a 20 inch barrel on my VTR. My last load I built was hitting 2550, but Hornady Tap comes out 2650 almost every time. I still need to chrono my Federal Gold Medal Match SMKs.

I have the program "shooter" for my android phone. It's my favorite thing about the phone. It seems to me that a lot of though was put into it. It has a lot of G1 and G7 profiles for bullets by Litz. Anyway I can't wait to see this round. I took my furthest shot this weekend at 650 yards. It's the furthest place I've found to shoot.

Sorry for the ramble, I just love shooting at distance.

[WRMETTLER]

Just paraphrasing, but it seems that a shorter, heaver, lead based bullet (no solid copper) that has a high rpm shot from a barrel with shallow, rounded grooves will pass through the transonic zone better than other sorts of bullets. Some posters claim their bullets are accurate 100s of yards beyond the transonic zone, with a couple of Englishman claiming they are shooting targets 2500 yds with .308 subsonic bullets.

Of course, the thread then degenerates into conversations about sabots with fins, true Mil sighting systems, solid copper bullets, etc. In my experience, some of these threads have the same structure as a herd of cats, and not just in that forum.

I’m sure there are people on this board who know about this stuff, but it sure isn’t me.

I suggest you sign on that board if your interested in rifle shooting. It’s free and they have some very interesting threads going.

[koz]

I talked to a USASOC buddy today who has tested some of the AB rounds - he said they shoot very well at 1000m.

[Buffalobob]

I talked to a USASOC buddy today who has tested some of the AB rounds - he said they shoot very well at 1000m.

If you go and read what Gene and Richard are saying about the old M118 Special Ball in the M14 thread it is very interesting being as the M21 is still widely used (I pulled that thread up with a stupid but true story as the best one I could find on this forum about the M21 and Special Ball). The 173 grain Full metal Jacket Boat Tail bullet itself was made by Lake City or Frankfurt arsenal. The stuff was really great at extreme ranges well past the transition zone. Even if you could get the M118LR stuff to be stable at the same distances the hollowpoint is not going to expand so expansion is not a consideration. Very few people do well with a 1/3 inch diameter hole through them so the FMJ BT was just as good as any other style bullet at those ranges.

It would be interesting to compare the shape of the Berger bullet with the 173 SB but I am sure Bryan L changed the nose profile in order to get a G1 of 0.5 but I bet the boat tail is the same

[Ramirez]

I think the price is pretty fair as well. My brother in law shoots, .257 weatherby Mag. It's around $70 a box! So far I've been doing well w/ 168g rounds, but then I also have only shot out to 650 yards.

[Gene Econ]

If you go and read what Gene and Richard are saying about the old M118 Special Ball in the M14 thread it is very interesting being as the M21 is still widely used (I pulled that thread up with a stupid but true story as the best one I could find on this forum about the M21 and Special Ball). The 173 grain Full metal Jacket Boat Tail bullet itself was made by Lake City or Frankfurt arsenal. The stuff was really great at extreme ranges well past the transition zone. Even if you could get the M118LR stuff to be stable at the same distances the hollowpoint is not going to expand so expansion is not a consideration. Very few people do well with a 1/3 inch diameter hole through them so the FMJ BT was just as good as any other style bullet at those ranges.

It would be interesting to compare the shape of the Berger bullet with the 173 SB but I am sure Bryan L changed the nose profile in order to get a G1 of 0.5 but I bet the boat tail is the same

Bob:

Took a look and it is marketing more so than anything else in my opinion. 7% improvement in BC? Show me how and prove it equates to a significant improvement of performance at those 'extended ranges'. Close down the tip and you will get four or five percent without any other change to the design.

What I find as being somewhat deceptive is the marketing. The marketing inferrs that because the numbers indicate 7% improvement in BC that one will see a 7% improvement at 'extended ranges', 'Improvement' "performance', and 'extended range' are vague and misleading when the implication is a significant improvement over what already exists.

One selling point is the length of the bullet but one can seat longer bullets deeper to feed from a magazine too and with the .308 it doesn't mean a thing where in other cartridges, increasing seating depth may mean dangerous pressures. The .308 is pretty forgiving.

I also read the SWAT article and they claimed 16 FPS per inch of barrel lost under 20" but only went down to 18". That by no means is enough information to make any conclusions but like most rags, they imply which is intellectually dishonest. Some cartridges need every foot per second of speed they can get and others don't. For SWAT purposes they don't need a 30" barrel. For Palma purposes given the rules of the sport plus the technology of today, one needs that barrel length to get speed.

The plus side is the brass is great and I am sure the bullets are just fine. Two dollars a shot is appalling for us who handload but for guys who don't or want to stock up on brass, the price really isn't bad at all. More power to Litz on this. No doubt he designed the bullet and no doubt the bullet is as good as any other top end 175 grain .30 caliber match bullet on the market.

However, maybe the real key to this discussion isn't technology or design but rather 'market'.

Gene

[Buffalobob]

Gene

I would ask you two questions just so we start at the same point of departure.

1. Do you believe the 175 SMK is stable through the transonic zone as it is my understanding that it is not; although, I have never personally verified it?

2. Do You believe the old M118 SB (173 gr FMJBT) was stable through the transition zone; as it is my understanding that it was, and that was my observation of it?


The official Americal record in RVN with the 308 is 1600 meters (not yards) and the unofficial is further.

[mojaveman]

The official Americal record in RVN with the 308 is 1600 meters (not yards) and the unofficial is further.

Remarkable.

With an M-21 or something else?

[Buffalobob]

Attached is an Adobe file about the Chu Lai Sniper School and, other than a few CIA test rifles, the snipers routinely used the M21 and Lake City M118 SB.

Lones Wigger is easy to find on the internet and we exchanged emails once about RVN records.

http://www.sports-reference.com/olympics/athletes/wi/lones-wigger-1.html

http://www.facebook.com/people/Lones-Wigger/1537531224

Virgil Umphenour runs a guide service with his son and daughter in Alaska

http://www.huntalaskawithus.com/about_huntalaska.htm

One day in RVN, Virgil sent word that he was going to court martial a "raggedy ass, wet behind the ears lieutenant" if I did quit being an asshole. :D I had tactical control of the snipers in the field but he had administrative control.


I would just say that my experience was about as the adobe file says. Lots of 100 - 500 yards kills and wounded and only very, very seldom are you in a situation to get a really good extreme range shot.

I believe the Iraq record with the 308 was set at 1250 meters with a M24 bolt gun using the M118LR (not M118 SB) with the 175 SMK and is borderline super sonic range but I don't know the atmospheric conditions so I would not make any definitive statement about it other than a good shot is a good shot.

[Gene Econ]

Gene

I would ask you two questions just so we start at the same point of departure.

1. Do you believe the 175 SMK is stable through the transonic zone as it is my understanding that it is not; although, I have never personally verified it?

2. Do You believe the old M118 SB (173 gr FMJBT) was stable through the transition zone; as it is my understanding that it was, and that was my observation of it?


The official Americal record in RVN with the 308 is 1600 meters (not yards) and the unofficial is further.

Bob:

I don't think anything is stable through the transonic zone. Not being a wise guy about it. The differences are probably in the degree of instability. I also figure twist rate and velocity would play a role as that determines nutation or precession -- both of which probably have something to do with stability when transitioning.

I can comment on my observations of consistency at 1K though.

I would give the 118LR an edge over the 118 SB at 1K in terms of consistency given shooters who are relatively new to distance shooting. The difference is evident but in my opinion both are more than adequate for combat demands. However, neither are competitive in today's precision shooting sports.

I can say with certainty that 118LR and 118 SB held considerably better at 1K than the old 852 Match. However, that old 168 grain bullet from the 852 had transitioned completely to subsonic under most environmental conditions. Also, the bullet design of that one simply wasn't focused towards performance much beyond 300.

I kind of look at it like this. Maybe one percent of the competitive side of long range shooting will be good enough at those distances where results can be conclusively shown to be due solely to instability caused by transonic passage. So, the 'so what' factor plays a role at least in my terms.

As for a 1600 meter shot with a M-21 and the old 118 Match you guys used in Vietnam. With an ART scope? You are looking at about ten minutes per hundred after 1K meters with that cartridge out of a 21 so somehow the guy held about sixty minutes over? Man, I can't see how the shooter could even see another human with an ART scope at that distance unless they were in a high desert right at sunrise with absolutely no wind or mirage. Not to mention someone being able to spot the shot.

I do defer to Rick or Sinister on the transonic issue and the 118's though. To me, the discussion is a technical one that can't be predicted and certainly can't be changed by the shooter. So, it just doesn't hit the level of importance for my purposes and in my conditions.

Gene

[Buffalobob]

I count it as a good day when I actually learn something new about long range shooting. And your comment is really intriguing to me so I am going to keep it in mind as it would seem to be a good assessment.

I don't think anything is stable through the transonic zone. Not being a wise guy about it. The differences are probably in the degree of instability. I also figure twist rate and velocity would play a role as that determines nutation or precession -- both of which probably have something to do with stability when transitioning.

So, I am about to the end of my knowledge base on the subject and only have a few thoughts and observations left.

You mention optics used back then and that certainly is important. In about 1977 I began noticing that the animals I hunted were often over othe next ridgeline so I bought a 3X9 Redfield Accutrac. That thing was so great under 500 yards that I built up a whole rifle and topped it off with a 6X18 Redfield accuRange. In its day and in my early years it was great glass. I sold the 6X18 about three years ago because it was trash compared to the new Luepolds and Nightforces. Whether is was the coatings and glue deteriorating or my eyes deteriorating or both I do not know. I also had a friend who built a USMC M24 clone and topped it with a RVN correct Redfield and I looked through it at 300 yards and it was trash although I never adjusted the eyepiece so that judgement is flawed. I have a Wilde Rangefinder (WWII vintage) and I can see clearly to 3K with it. So I am not at all certain about the optics of the RVN era versus what I use today.

However you make this comment
can't see how the shooter could even see another human with an ART scope at that distance unless they were in a high desert right at sunrise with absolutely no wind or mirage. Not to mention someone being able to spot the shot.

As I mentioned earlier, there is the 1600 M official Americal record and then there is the "unofficial" record. After the Americal left RVN, the 196th LIB operated as an independent unit. The whole long story of how that record was broken is hilarious but I will save it for another day.
I will preface my remarks that everything hinges upon my memory which is about as reliable as my other body parts. :D

The firing position was the top of a perimeter bunker at Bn Firebase on a ridge and downhill to the old French RR. The background was a water filled rice paddy. Target was two NVA solder walking ( Can you believe shooting a guy walking at over a mile with a 308?) along the RR. Shooter was a second tour sniper using a M21, ART and M118SB with his regular partner spotting on the Bn arty spotting scope. Spotter was calling adjustment based upon splashes in the rice paddy and the NVA reactions. Fourth and fifth round hits on the same guy. One more for the Body Count Board!

Unusual and unique circumstance under which the shots were made and for certain no other sniper I ever had was good enough to do it.

So before I conclude, I will say that my son and my daughter and myself have won mantel trinkets shooting the 175 Sierra MatchKing in long range F-class and several animals have been killed with it which have been posted on this forum. Its a great bullet and I have some loaded right now just for hunting. I also shoot Bergers and have killed several animals beyond 1K with them so they are also good bullets.


Conclusion

Given the great improvements in metallurgy and barrel making and the great improvement in optics, rangefinding, atmospheric meters and handheld ballistic computers and given the continued widespread use of the 308 as a sniper cartridge is seems that one would stop and think whether the bullet in use is limiting the effective range of the snipers because it will not transition well. Back in the good ole days Sniper School was three weeks. Nowadays it is much longer and much improved (I would hope) and the snipers should be capable of outperforming those of my generation. Why aren't the RVN records being broken? Is it because of bullet design?

[Gene Econ]

So, I am about to the end of my knowledge base on the subject and only have a few thoughts and observations left.

You mention optics used back then and that certainly is important. In about 1977 I began noticing that the animals I hunted were often over othe next ridgeline so I bought a 3X9 Redfield Accutrac. That thing was so great under 500 yards that I built up a whole rifle and topped it off with a 6X18 Redfield accuRange. In its day and in my early years it was great glass. I sold the 6X18 about three years ago because it was trash compared to the new Luepolds and Nightforces. Whether is was the coatings and glue deteriorating or my eyes deteriorating or both I do not know. I also had a friend who built a USMC M24 clone and topped it with a RVN correct Redfield and I looked through it at 300 yards and it was trash although I never adjusted the eyepiece so that judgement is flawed. I have a Wilde Rangefinder (WWII vintage) and I can see clearly to 3K with it. So I am not at all certain about the optics of the RVN era versus what I use today.

However you make this comment


As I mentioned earlier, there is the 1600 M official Americal record and then there is the "unofficial" record. After the Americal left RVN, the 196th LIB operated as an independent unit. The whole long story of how that record was broken is hilarious but I will save it for another day.
I will preface my remarks that everything hinges upon my memory which is about as reliable as my other body parts. :D

The firing position was the top of a perimeter bunker at Bn Firebase on a ridge and downhill to the old French RR. The background was a water filled rice paddy. Target was two NVA solder walking ( Can you believe shooting a guy walking at over a mile with a 308?) along the RR. Shooter was a second tour sniper using a M21, ART and M118SB with his regular partner spotting on the Bn arty spotting scope. Spotter was calling adjustment based upon splashes in the rice paddy and the NVA reactions. Fourth and fifth round hits on the same guy. One more for the Body Count Board!

Unusual and unique circumstance under which the shots were made and for certain no other sniper I ever had was good enough to do it.

So before I conclude, I will say that my son and my daughter and myself have won mantel trinkets shooting the 175 Sierra MatchKing in long range F-class and several animals have been killed with it which have been posted on this forum. Its a great bullet and I have some loaded right now just for hunting. I also shoot Bergers and have killed several animals beyond 1K with them so they are also good bullets.


Conclusion

Given the great improvements in metallurgy and barrel making and the great improvement in optics, rangefinding, atmospheric meters and handheld ballistic computers and given the continued widespread use of the 308 as a sniper cartridge is seems that one would stop and think whether the bullet in use is limiting the effective range of the snipers because it will not transition well. Back in the good ole days Sniper School was three weeks. Nowadays it is much longer and much improved (I would hope) and the snipers should be capable of outperforming those of my generation. Why aren't the RVN records being broken? Is it because of bullet design?

Bob:

Don't want to make a mess of this one so will be careful about what I say.

I have shot the 24 with the issued M-3 optic at about 1250 - 1300 meters and had to put on all elevation and hold at the base of the duplex. That got the 118 SB out to about 1300. If I had to push it another hundred meters, it would have been impossible for me to see the target through the optic. It brings up something. How could the shooter have seen the targets with that ART scope at that distance? From what I can recall about the ART Scopes, you maxed them out at 1K and I can't see how someone could see a target through their scope at 1600 meters using the type of hold over needed. Just food for thought.

As for guys doing or not doing what this one team did in Vietnam I can only offer some potential reasons. First is that the guys today must ID the target as a threat. Since the enemy doesn't wear a uniform, this means they must see a weapon. Hard to do at those distances with a 10X optic. Also, the conditions you mentioned are very unique. Team on a hill, enemy crossing a rice paddy. Ability to see the bullets literally splash in the water which is way more precise than seeing dust kick up. And in a ten year long war it happened only once.

Technology has gotten better but not significantly better unless you get into night vision and thermals. The old 173 grain service bullet was designed in the 1930's and improvements in design have happened but not enough to make a significant difference in danger space -- which equates to hit probabilities. Basically, the 118 SB and LR are 600 meter shooters and I would bet that if accurate records were kept you would find the majority of one or two shot engagements with 118 SB or LR resulting in a hit happened under 600 meters with the majority at 500 or less.

Another thing to consider and also is probably a reason why no one cares about record keeping is this. When does a shot stop being due to skill and more due to luck? Three shots -- four -- five? That is the big problem if the goal is to see who got the longest shot with a 7.62 rifle.

About the only thing I can say with certainty is that the guys will take the shot if they are allowed to under what ever ROE they must follow and if it means a shot past a reasonable distance, they will certainly try. I can not speak for SF here so understand I am talking about the Infantry. Maybe some SF guys have done the same? I would not know but I do know that some Infantrymen have been successful at distances past 1K but it certainly isn't the rule.

Gene

[Peregrino]

SF shooters have also been successful beyond 1000M in the current conflicts, sometimes with .308s, more often with .300s and .338s. I think there's even a couple of .50s out there. I'm not aware of any one-shot kills beyond about 1200m by anybody with any weapon/ammo combo. Even the "records" touted here in other threads. All (that I'm aware of) have required adjusting fire and using compensated aimpoints (and targets that accept "enshalah" as a fact of life). It doesn't count as "sniping" when it amounts to the same thing as hitting a target in a MG's beaten zone.

I like the M21 as well as anyone - it's the first DM rifle SF taught me to shoot. It's a sweet 600m rifle despite the POS ART II scope (OK - so I'm nostalgic about wood stocks). Hitting targets with one at 1200m+ (especially with M118SB) is luck and claiming otherwise is the same as claiming a shit shot in a pool tournament.

[Gene Econ]

I have heard the new 155 palma Sierra match king is an exellant 1000 yard bullet. Its BC is

.504 @ 2700 fps and above
.470 between 1800 and 2700 fps
.430 between 1500 and 1800 fps
.380 @ 1500 fps and below

The 175 gr is as follows

.505 @ 2800 fps and above
.496 between 2800 and 1800 fps
.485 @ 1800 fps and below

Soo in theory the 155 should be better at long range in the 308 since getting 2800 fps out of the 308 with a 175 is pushing the pressure limits while 2700 fps or a little better is a little more doable.

For the 30-06 or 300 WM I am thinking the 190

.533 @ 2100 fps and above
.525 between 2100 and 1600 fps
.515 @ 1600 fps and below

or the 220 gr sierra match kings would be a better choice

.629 @ 2100 fps and above
.624 between 2100 and 1700 fps
.608 @ 1700 fps and below

http://www.sierrabullets.com/index.cfm?section=bullets&page=bc&bullettype=0

Anyone have any thoughts?

Now I realize all things being equal heavier bullets retain velocity better but the differance in BC etc I am thinking the 155 MIGHT be a better choice for long range in the 308.

BO:

Any of the match grade 155's are excellent bullets. Note they were designed very specifically for Palma shooting. Generally they use a 1 turn in 13 inch twist, 30 inch long barrel in order to stabilize that specific bullet and to get the 2950 plus FPS needed to ensure it is above the speed of sound at 1K. International Plama rules demand a bullet of 155 grains or lighter and 7.62 / .308 cartridge. US Palma lets you shoot any bullet weight but it must be .30 caliber and I believe is restricted to the .308 cartrdge. Understand that Palma rifles are also restricted in weight.

So, in a way you see why those bullets were designed the way they are. To feed a very specific need of a very specific sport. Would they be fine for military purposes? I don't think so because you don't see 30 inch long barrels on M-24's and you need that speed for that shorter and lighter bullet to stay above the speed of sound.

Personally and for military applications I see .30 caliber bullets weighing in the 170 - 180 grain range is about ideal to maximize danger space given 20 inch + - barrel lengths, a requirement to keep the bullet length down to maximize available cartridge capacityand magazine seating, while allowing for a fast enough velocity for performance to practical combat ranges -- which I see as 600 meters or less but the Army sees as 800 meters or less.

Another thing you need to consider is recoil effects. The higher the recoil, the more negatively it affects the shooter. A 155 Palma load is very hot -- too hot to blast regularly from standard receivers but its recoil is still noticeably less than a round of 118 shot from a 24 or 110. That means a-lot when talking about blasting those antique 190's and 220's.

Oh yes, note I did not get into BC comparisons. Although they are of value in decisions on ammunition that shooters make, you will never see them become the primary factor. Accuracy, velocity, and terminal effects are generally the primary issues going into a decision on some sort of cartridge and bullet. Those three get mixed up in priority based on the specific need but those are generally the three issues involved with decisions. BC's get involved after initial decisions are made and a guy has narrowed down his potential choices. Even then, they may not mean anything.

As a general rule, from the barrel to 300 the BC has very little meaning. From 300 - 500 it has some meaning and from 600 out it does have meaning you can actually see in reality. But only when you are looking at equal velocities and BC differences of at least 5 %.

Gene

[Buffalobob]

For the 308 or any other caliber, each increase in muzzle velocity of 100 fps is only going to give about a 50 yard increase in range.
For BC if you increase it by 10% then you get a 10% increase in range. For a given cartridge both muzzle velocity and BC have practical limits on the amount you can increase them. One should keep in mind that BC is tied to sectional density and muzzle velocity is tied to weight.

What Litz has done is change the shape factor without sacrificing either BC nor sectional density and gained large increases in yardage out to whatever range the shooter and spotter have the skill to achieve with the equipment they have available.

[Buffalobob]

I ordered a box of the bullets for my 308. Here are a couple of pictures of the box and then there is a picture of two Sierra 175 MK on the left and two Berger 175OTMs on the right. It was misting rain at the time of the picture.

[Buffalobob]

Deer season starts Saturday after Thanksgiving so I needed to go to the rifle range to check some zeros and took along some loads for the OTMs to test for accuracy. I normally shoot 43.4 grains of Varget in RWS cases for competition with the Sierra 175 MK and on calm days that will group about 0.3-0.4 for three shots. For this test I am using Winchester cases that have about 1 grain more volume than RWS but are less consistent in quality. It was gusting wind up to 5mph today so groups were a little more open.

First picture is of the standard 175MK loads where I am adjusting the zero between the top 3 shot group and the bottom 3 shot group. Aim point is the upper right corner of the tape.

Second picture is the Berger 175 OTMs with three different charges of Varget and 5 shot groups instead of 3 shot groups. All three groups go just under 0.5 for five shots. This is acceptable accuracy for me and this particular rifle.

I think I will try them out on deer this season and see how they work.
It will probably be a long time before I get to test past transonic ranges so don't be holding your breath waiting on it. :D

[Sinister]

The second edition of Litz' book is very good and fairly easy to understand. There are a few errors but he gives a good explanation of the difference between secant and tangent ogive bullets and the ballistic differences between shorter and longer boat-tailed projos.

I am guessing but Litz and Berger have done extensive recent original art designing "Hybrid" bullet profiles, melding what they consider the best of both tangent and secant ogives. I assume that's what they've done with the 175.

My experience with 300-grain .338 Lapua Magnum projos has Sierra Match Kings running out of steam around 1600 Meters (they definitely do NOT fly true transitioning thru trans-sonic); Bergers around 1800; and Lapua Scenars right about 2 klicks (all using the same primer, brass, and powder charges).

RUAG (Switzerland) has a new proprietary 300-grainer they are adding to their Swiss-P line that is aimed at meeting USSOCOM's 1500-meter PSR spec as well.

[Peregrino]

----- My experience with 300-grain .338 Lapua Magnum projos has Sierra Match Kings running out of steam around 1600 Meters (they definitely do NOT fly true transitioning thru trans-sonic); Bergers around 1800; and Lapua Scenars right about 2 klicks (all using the same primer, brass, and powder charges).

RUAG (Switzerland) has a new proprietary 300-grainer they are adding to their Swiss-P line that is aimed at meeting USSOCOM's 1500-meter PSR spec as well.

OK - Slightly off topic but you've got my undivided attention. Have you had an opportunity to look at the Hornady 285gr .338 Bullet yet?

PS - You coming to Bragg next month for the sniper competition?

[Sinister]

I've looked at the Hornady 285s but not shot a bunch (maybe 20 rounds). I have a photo somewhere with sectioned Hornady 285, Scenar, and Match King or Berger side-by-side. The Hornadys are interesting in that the nose of the projo is hollow (like a 308 155-grain Scenar) while the jacket is nearly the same length as the 300-gr Scenar, pushing the center-of-gravity towards the rear.

We're getting to Fayetteville on Wednesday night (the 7th).

[mark46th]

Brush- I have a Rem 700Mlr in .338 Lapua. It is just a factory rifle with a stock muzzle brake. It has much less recoil than my son's M70 .300 Winmag. It is not as bad as people make it out to be. I have only had it for about 8 months. I use the 300gr SMK with good results. Now I have to buy a better rangefinder, though....

I should add that I am a rookie at this and no where near the class of the other QP's commenting on this thread. My comment was on the recoil remark only...

[Buffalobob]

As I mentioned in post #34 I would try to test the transonic stability of the bullet. This has finally happened and as luck would have it the test weather conditions were pretty raggedy but I shot anyway.

Because I do not have access to a 1500 yard range I decided to develop a reduced velocity load that would go subsonic at about 700-750 yards. One of my loading manuals had a starting load for 175 grain bullets and Varget so I put together a load with a muzzle velocity of 2250 fps. This load was tested for accuracy at 100 yards by firing two groups from the bench. Groups size CTC was less than 0.4.

Ttransonic stability was tested during a F-class match at R4 Quantico USMC. There was the worst headwind I have experienced in the last six or seven years. It was about 20 mph and varying from 10:00 to 2:00. During the unlimited sighter stage at 800 yards the rifle was zeroed for the 155.5 Berger (MV= 2800fps) that I normally compete with and also the 175 OTM (MV-2250fps). The 800 yard stage was fired with the 155.5 Berger and produced an average per shot score of 9.3 which was probably the best score I have ever gotten at that stage. The “open” rifles were averaging about 9.0. But what I got was a period of wind that stayed at 11:00 so I didn’t have the direction switches that are so damaging to the score. So the test was off to a bad start being as I had shot about 5 points better than normal under some of the worst conditions.

At 900 yards I used the 175 OTMs and got a per shot average of 7.3 being as the wind was back to switching direction. At 1000 yards I went back to the Berger 155.5 and got a per shot average of 6.75. Those of us shooting “FTR” (308) were recording misses off of both sides of the target because the wind was so unpredictable. The interesting thing is that the subsonic, slow moving 175 OTM produced a higher per shot score than the faster supersonic 155.5 Berger at the 100 yards difference --- 7.3 vs 6.75. This is about a half MOA difference.

So I conclude that the 175 Berger even when it is well below the transonic zone still retains very good accuracy.

For those who forgot, I tested terminal performance of the 175 OTM at normal velocity on a deer in this thread.


http://www.professionalsoldiers.com/forums/showthread.php?t=36001