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Box
05-04-2009, 21:45
I need some good information on shooting 5.56 through short barreled guns...

-What effect does the short barreled SAW have on the efficiency of the 5.56 ammo?
-Is there any ballistic (or any other "real" benefit) benefit over using 5.56 ammo in guns with a ten inch barrel ?
-Is there documented results as opposed to "I like the short barrels because... "

I suspect that there is little or no real benefit over the carbine barrel except for the fact that it allows some guys to look cool and feel good about their image, but I am not a ballistics expert, I am just a bit curious of this new found fascination with short barrels by new guys. I can only find info that supports a decrease in effectiveness with short barrels using military grade ammo.

Keep in mind I am only interested in milspec weaponry using standard issue 'green tip' ammo, not custom grade barrels made with different rifling twist and specialty or non-standard ammo.

Somebody smart please square me away so I can be smart also.

The Reaper
05-04-2009, 22:15
PM sent, Billy.

TR

Box
05-04-2009, 22:23
Many thanks sir.
That helps a ton.

18C4V
05-05-2009, 01:05
PM sent, Billy.

TR

Sir,
Can you send me that info too?

The Reaper
05-05-2009, 08:55
This has been discussed here and elsewhere. Let me hit the highlights and provide an executive summary.

Like many things in life, it is a compromise. Shorter barrels equal lower muzzle velocity, period. Lower muzzle velocity, for the 5.56, is a bad thing. It seriously affects lethality, and makes shot placement harder due to increased bullet drop.

M855 ammo exacerbates this problem. It is slower, less effective, shorter range, and less accurate than the M193 it replaced. The Mk 262 is a better choice for most purposes, if you can get it, and it is much more accurate than the M855 or the M193, for that matter.

Since the M-16 was designed to function with a 20" barrel, anything less represents a potential reliability problem. 20" M-16s run, almost always reliably. 18" SPRs usually present no problems. 16" M-4s are almost as good. 14.5" M-4s are starting to get to the barrel length where problems pop up. A 10.5" or 11.5" CQB-R is really a race car. When it runs, it runs at the bleeding edge of reliability. Some do not run out of the box. The ones that do will require significantly more care and maintenance to keep running.

A 10.5" should really be treated as a submachine gun. If you are in a vehicle or doing dedicated CQB with little need to engage targets beyond 25 meters, it is a great weapons package. You can hit targets well beyond that range, but shot placement is going to be critical. It is also more easily concealed than the M-4 or M-16. IMHO, too many people carry them because of the CDI factor and they look cool.

The 14.5" M-4 is a carbine. It is able to reach out and put targets down reliably out to 100 meters or so. It has some of the advantages of the CQB-R, and some of the same disadvantages. If you need a weapon to do everything, with a healthy dose of vehicle, aircraft, or CQB work, yet still need to reach out a little further on occasion, the M-4 is your baby. Honestly, it should not be the dedicated weapon for a conventional infantryman in a non-CQB environment.

If you need the gun to be completely reliable, to reach out beyond 100 meters and drop people regularly to 200 or so, provide better precision, yet do not do a lot of mounted or airmobile infiltration, and have little need for a CQB weapon, then the M-16 rifle is your baby. If you are in OEF and are getting into far ambushes and engagements beyond grenade range, you need the rifle, not a carbine or SMG.

The full-length M-249 SAW is a squad automatic weapon. The shorter version is a specialty weapon, and if you have to ask, you aren't special enough to need one.

In my opinion, the shorter barrels are more status symbols than anything else. "Look at me, I'm special!" If you are doing dedicated CQB, PSDs, or almost exclusively mounted ops (and shooting the weapon from inside the vehicle), the 10.5" CQB-R might make sense. If you are not, the M-4 is a better choice, more effective, and more reliable as well.

Just my .02, YMMV.

TR

koz
05-05-2009, 11:04
I chrono'd some M193 from a 10.5" barrel - it averaged 2350fps. I used the www.handloads.com/calc/ for the numbers

Here's the chart -
55gr , BC - .221 (based on velocity), 2350 fps, standard atmosphere,

Range FPS Energy ft/lbs
0 2350 647
50 2157 568
100 1978 478
150 1810 400
200 1652 333
250 1506 277
300 1375 231

charlietwo
05-05-2009, 12:08
Many thanks, Reaper. Nothing beats hip pocket training :)

MeC86
05-05-2009, 14:50
Thanks for the info. I use a 10.5 inch and was curious about how the QP's felt about them.

koz
05-05-2009, 16:50
I was interested in the necessary fps for the M193 to fragment. So I did some searching and it seems like the consensus: 2500-2700 fps are needed for the bullet to fragment. Like TR said, it's like a sub-gun. Not much lethality (except with good shot placement) past 25m.

The Reaper
05-05-2009, 17:47
I have gotten closer to 2500 fps from the 10.5" barrels with M193, but it is still not something you can count on to fragment.

Those who can use ammo other than Ball have some additional options.

TR

st1650
05-08-2009, 08:33
I'm starting handloading .223 and I was wondering if any of you had SD load suggestions for a 11.5" 1/9 twist Armalite barrel. I think I would be better served with a 1/7 but it'll have to wait.

So far I've been using RUAG 63gr 5.56. http://en.wikipedia.org/wiki/Gw_Pat.90
Sub-moa with my 4x TA31 at 100yrds. Haven't chrono'd it yet. Should I stay with it or try some heavier grain, I've been looking at Hornady 68gr BTHP, SMK BHPT 69 gr.


As for reliability, I know it can't compare with the field, but I've never had any malfunction on mine. (Shot close to 10k of rounds).

Brush Okie
12-09-2011, 00:30
I am looking for recommendations on ammo for self defense out of an 16" bbl AR with a 1-12 twist. I was looking at the Hornady Vmax 55 gr but not sure if it would expand to fast especially after looking at the shooting link posted in another thread where the 55 gr TAP was ineffective. The rifle would be carried in the mountains and range would be 100 yards or less. Hard to articulate a threat that is 500 M away.

JJ_BPK
12-09-2011, 06:48
I am looking for recommendations on ammo for self defense out of an 16" bbl AR with a 1-12 twist. I was looking at the Hornady Vmax 55 gr but not sure if it would expand to fast especially after looking at the shooting link posted in another thread where the 55 gr TAP was ineffective. The rifle would be carried in the mountains and range would be 100 yards or less. Hard to articulate a threat that is 500 M away.


I would try the heaviest slug you can accurately throw at 200 yds..

1:12 is slow and normally lends itself to light slugs,, but you may be able to get the 62gr to acceptable levels. I'd try some M855A1.. or heavery slugs like Federal Gold Medal Match 77gr. BTHP..


Once the M855A1 replaces the leaded M855, it will reduce the amount of lead in production by approximately 2,000 metric tons yearly, based on the amount now used to make the M855.

C Attached..


Acceptable accuracy is the key. If the critter has a 15 MOA bull on their chest,, 5 MOA may be OK..

Air.177
12-09-2011, 07:06
I am looking for recommendations on ammo for self defense out of an 16" bbl AR with a 1-12 twist. I was looking at the Hornady Vmax 55 gr but not sure if it would expand to fast especially after looking at the shooting link posted in another thread where the 55 gr TAP was ineffective. The rifle would be carried in the mountains and range would be 100 yards or less. Hard to articulate a threat that is 500 M away.


I would test the waters and see just how heavy a bullet you can get away with and still retain the accuracy standards you are looking for. I think the 70/75/77gr stuff is pretty much out of the question unless you go to a different upper, but check out the Federal 62 gr "tactical bonded" stuff and also Black hills loads a 50 gr Barnes TSX that while quite light for my preference, would also be worth looking into.

HTH

Good times,
Blake

Team Sergeant
12-09-2011, 07:29
I am looking for recommendations on ammo for self defense out of an 16" bbl AR with a 1-12 twist. I was looking at the Hornady Vmax 55 gr but not sure if it would expand to fast especially after looking at the shooting link posted in another thread where the 55 gr TAP was ineffective. The rifle would be carried in the mountains and range would be 100 yards or less. Hard to articulate a threat that is 500 M away.

I'd answer your question but every time I try your avatar breaks my concentration.:rolleyes:

35NCO
12-09-2011, 07:42
In "Surefire-Combat Tactics" Fall 2011 volume 9, number 2 There is a very substantial scientific study on short barrels. The study was conducted by Dr. Philip H. Dater of GEMTECH. I hate these types of magazines, but whenever Dr. Dater publishes something, I read it.

The study starts with a 24" barrel and they keep measuring pressures until they reach 5 inches. The barrel was hacked off at 1" increments. The study also covers the relationship of velocity and barrel length. Incredibly interesting stuff if your putting a can on a short barrel. You may be able to find the study without buying the magazine. I don't think I can legally type it all in here, but I will post two examples for the sake of interest.

A 24" Barrel has a port pressure of 4,800 PSI with a Velocity of 2,964FPS and a sound level of 162.5dB(A)

A 10" Barrel has a port pressure of 12,140 PSI with a Velocity of 2,575FPS and a sound level of 164.3 dB(A)

The study was conducted to MIL-STD 1474D the ammo was M855 from the same lot.

Study also proves that barrels less than 10 inches on VSBR's are absolutely not worth it. Also, VSBR's will most certainly blow up your can after a very short period.

koz
12-09-2011, 09:51
I wouldn't use M855 for anything self defense related (unless that's the only ammo I had available). The 1:12" twist isn't great for heavier bullets. I've shot some Coyotes with the military contract Black Hills Barnes TSX 50gr. They have released it for commercial sale. It works well killing things. That seems like a light bullet but it does the job it's designed for. But expect some sticker shock.. $70 for 50rds.

http://www.ammunitiontogo.com/product_info.php/pName/50rds-556-nato-black-hills-barnes-tsx-50gr-hollow-point-ammo/manufacturers_id/66

Brush Okie
12-09-2011, 10:39
I wouldn't use M855 for anything self defense related (unless that's the only ammo I had available). The 1:12" twist isn't great for heavier bullets. I've shot some Coyotes with the military contract Black Hills Barnes TSX 50gr. They have released it for commercial sale. It works well killing things. That seems like a light bullet but it does the job it's designed for. But expect some sticker shock.. $70 for 50rds.

http://www.ammunitiontogo.com/product_info.php/pName/50rds-556-nato-black-hills-barnes-tsx-50gr-hollow-point-ammo/manufacturers_id/66

OUCH

Yea I was thinking 55 gr something. I might just try some vmax and see how it does. Going over the report I realized that it was at very close range so the velocity was very high, perhaps that is why they did not penetrate. I plan on using vmax bullets for coyotes so I will see how they perform. For CQB ranges I prefer a 12 gauge shotgun with 00 buck.

Thanks for the feedback.

frostfire
12-09-2011, 22:05
I wouldn't use M855 for anything self defense related

aw shoot, I was slinging that green tip from a Beretta ARX160 today with Leupold CQT. Once I figured out the hold-off, it touched half E-type silhouette consistently at 200m....from a 12 inch barrel. For something concealable, that's not bad at all. So I guess at 200m, the lethality is questionable? Inadequate muzzle velocity from a 12inch? :confused:

Brush Okie
12-09-2011, 22:43
aw shoot, I was slinging that green tip from a Beretta ARX160 today with Leupold CQT. Once I figured out the hold-off, it touched half E-type silhouette consistently at 200m....from a 12 inch barrel. For something concealable, that's not bad at all. So I guess at 200m, the lethality is questionable? Inadequate muzzle velocity from a 12inch? :confused:

The military is limited to non expanding ammo and that is NOT the best for self defense. The M855 has a reputation of going straight through people and not stopping them. In Somalia there were stories of Rangers and D boys getting 3-4 good center mass impacts and the enemy kept coming due to being on khat. Since they are designed not to expand they must rely on other things such as yaw and secondary wound chamnnel caused by high velocity. That is too much for me to get into here about wound ballistics.

An expanding bullet is designed to mushroom at a specific rate at a specific velocity range. For small game the bullets are designed to expand rapidly so on a human or large game they may expand too fast and not penetrate to the vitals. A bullet designed for large game if you hit say a coyote will go through without expanding and not make a clean kill.

Same with velocity of the bullets. If they are within the expected velocity range they work. If they are not going fast enough such as 200 meters from a short bbl they will not expand. If they are going above the specific velocity range such as if it is fire from 5 feet it may expand too fast and leave a large ugly wound that does not penetrate to the vitals and stop the person and or animal.

I am looking for a bullet for self defense. The issue is the 1:12 twist of te older rifle. They will stabilixe 55 gr or lighter. For heavier bullets you need a faster twist barrel. Actually it has to do with the length of the bullet according to the greenhill formula but heaver bullets tend to be longer.

The Reaper
12-09-2011, 23:15
aw shoot, I was slinging that green tip from a Beretta ARX160 today with Leupold CQT. Once I figured out the hold-off, it touched half E-type silhouette consistently at 200m....from a 12 inch barrel. For something concealable, that's not bad at all. So I guess at 200m, the lethality is questionable? Inadequate muzzle velocity from a 12inch? :confused:

Not for punching paper.

IRT the OP, I think that issue type M193 will be just fine for social work at 100 yards or less.

If you have to penetrate vehicles or such, try the bonded as Air.177 recommended.

A 1:12 WILL NOT stabilize a heavy bullet and will it most likely start yawing till it stabilizes base first. I doubt that you will be able to hit anything with it at 50 yards, much less 100.

The M193 and M855 will work fine and will fragment, causing significant damage if they hit the target going 2700 fps or better. Sometimes down to 2500fps , but not reliably. This is discussed in detail elsewhere on this forum.

TR

WholeManin2010
12-10-2011, 19:08
I am looking for recommendations on ammo for self defense out of an 16" bbl AR with a 1-12 twist. I was looking at the Hornady Vmax 55 gr but not sure if it would expand to fast especially after looking at the shooting link posted in another thread where the 55 gr TAP was ineffective. The rifle would be carried in the mountains and range would be 100 yards or less. Hard to articulate a threat that is 500 M away.

Aside from M193, I would suggest RBCD's Total Fragmenting Soft Point round. I haven't killed anything with it, but I have fired a respectable number of their 90 gr .45acp TFSP round through an HK45c while testing for functionality and relative accuracy. No complaints aside from a hellacious muzzle flash. The 37 gr .223 ammo boasts 3880 fps and 1337 ft lbs -- should be plenty hot for PD, and light (and short) enough for your 1/12 twist.

The_Mentalist
06-20-2013, 05:45
Some of the issues with short barrel rifles (or AR pistols) make them pretty much useless in the real world. Although, as previously posted, a VSBR or SBR may be appropriate for vehicular operations with close proximity targets, typically, anything below a 16" barrel will cause performance degradation. Lower velocity due to incomplete burning of the powder, excessive flash and greater stress on the operating system due to gas pressures in a shorter system.

The round (cartridge) is designed to give the best performance when all powder is burned and gas expansion is maximized as the bullet reaches the muzzle. Designing a round for 5 grains of powder when the barrel is only long enough to have burned 4 grains before the bullet exits the barrel would be fruitless. You would have to go to a faster burning powder in order to reach proper pressures at the muzzle. But, then you face the issue of excessive chamber pressures. Over pressurize the chamber and you have problems ranging from case separation to blown primers to outright explosions. Also, driving the bullet too fast from the chamber can cause excessive skipping of the round before the rifling can catch. This reduces accuracy by imparting inadequate spin to stabilize the bullet.

We see/hear a lot about ballistics. Too many people only know about external ballistics which is what the bullet does in the air. But, we must also consider internal ballistics which is what happens between the primer strike and the bullet leaving the muzzle. Also, and IMHO the most important is terminal ballistics. What happens upon impact. Does it have enough velocity to allow for full expansion at the vitals of the specific target or does it have too little or too much? Would you use a round designed for a 200lb man to kill rabbits? Would you use a varmint round on a man? Although with proper placement, either of these rounds could be made effective, they are not interchangeable.

Excluding FMJ milspec rounds due to their lack of expansion (thank you Geneva and Hague conventions for taking common sense out of munitions) I would personally recommend a 55 to 62 grain ballistic tip (Barnes X for example) fired from a 16 to 20" barrel with a 1 in 7 to a 1 in 9 twist rate.

I personally use a 16" American Spirit Arms barrel with a 1 in 7 twist and get sub MOA accuracy with a 62 grain Barnes X tipped round. I do use milspec for plinking, but for defense it is the Barnes. I also use the equivalent 155 grain round in my .308 fudd gun. For my handguns, I like the Hornady critical defense which is the pistol caliber equivalent.

I am old school when it comes to weapons. Specific round for specific purpose for specific weapon. Fudd gun for extreme range, AR to 300 yards (but will go further for varmint hunting) and 45ACP for carry. Of course it is a 1911.

Team Sergeant
06-20-2013, 10:20
Some of the issues with short barrel rifles (or AR pistols) make them pretty much useless in the real world. Although, as previously posted, a VSBR or SBR may be appropriate for vehicular operations with close proximity targets, typically, anything below a 16" barrel will cause performance degradation. Lower velocity due to incomplete burning of the powder, excessive flash and greater stress on the operating system due to gas pressures in a shorter system.

The round (cartridge) is designed to give the best performance when all powder is burned and gas expansion is maximized as the bullet reaches the muzzle. Designing a round for 5 grains of powder when the barrel is only long enough to have burned 4 grains before the bullet exits the barrel would be fruitless. You would have to go to a faster burning powder in order to reach proper pressures at the muzzle. But, then you face the issue of excessive chamber pressures. Over pressurize the chamber and you have problems ranging from case separation to blown primers to outright explosions. Also, driving the bullet too fast from the chamber can cause excessive skipping of the round before the rifling can catch. This reduces accuracy by imparting inadequate spin to stabilize the bullet.

We see/hear a lot about ballistics. Too many people only know about external ballistics which is what the bullet does in the air. But, we must also consider internal ballistics which is what happens between the primer strike and the bullet leaving the muzzle. Also, and IMHO the most important is terminal ballistics. What happens upon impact. Does it have enough velocity to allow for full expansion at the vitals of the specific target or does it have too little or too much? Would you use a round designed for a 200lb man to kill rabbits? Would you use a varmint round on a man? Although with proper placement, either of these rounds could be made effective, they are not interchangeable.

Excluding FMJ milspec rounds due to their lack of expansion (thank you Geneva and Hague conventions for taking common sense out of munitions) I would personally recommend a 55 to 62 grain ballistic tip (Barnes X for example) fired from a 16 to 20" barrel with a 1 in 7 to a 1 in 9 twist rate.

I personally use a 16" American Spirit Arms barrel with a 1 in 7 twist and get sub MOA accuracy with a 62 grain Barnes X tipped round. I do use milspec for plinking, but for defense it is the Barnes. I also use the equivalent 155 grain round in my .308 fudd gun. For my handguns, I like the Hornady critical defense which is the pistol caliber equivalent.

I am old school when it comes to weapons. Specific round for specific purpose for specific weapon. Fudd gun for extreme range, AR to 300 yards (but will go further for varmint hunting) and 45ACP for carry. Of course it is a 1911.

What "real world" do you live in? One that thinks a 100+ year old design is state of the art? :rolleyes:

11Ber
06-20-2013, 10:20
Some of the issues with short barrel rifles (or AR pistols) make them pretty much useless in the real world.


You might know more about weapons than I do since I am a medic. I will also admit that "shorties" have their disadvantages but this quote is just silly. I will personally attest to their usefulness.

koz
06-20-2013, 15:43
Some of the issues with short barrel rifles (or AR pistols) make them pretty much useless in the real world. Although, as previously posted, a VSBR or SBR may be appropriate for vehicular operations with close proximity targets, typically, anything below a 16" barrel will cause performance degradation. Lower velocity due to incomplete burning of the powder, excessive flash and greater stress on the operating system due to gas pressures in a shorter system.

The round (cartridge) is designed to give the best performance when all powder is burned and gas expansion is maximized as the bullet reaches the muzzle. Designing a round for 5 grains of powder when the barrel is only long enough to have burned 4 grains before the bullet exits the barrel would be fruitless. You would have to go to a faster burning powder in order to reach proper pressures at the muzzle. But, then you face the issue of excessive chamber pressures. Over pressurize the chamber and you have problems ranging from case separation to blown primers to outright explosions. Also, driving the bullet too fast from the chamber can cause excessive skipping of the round before the rifling can catch. This reduces accuracy by imparting inadequate spin to stabilize the bullet.

We see/hear a lot about ballistics. Too many people only know about external ballistics which is what the bullet does in the air. But, we must also consider internal ballistics which is what happens between the primer strike and the bullet leaving the muzzle. Also, and IMHO the most important is terminal ballistics. What happens upon impact. Does it have enough velocity to allow for full expansion at the vitals of the specific target or does it have too little or too much? Would you use a round designed for a 200lb man to kill rabbits? Would you use a varmint round on a man? Although with proper placement, either of these rounds could be made effective, they are not interchangeable.

Excluding FMJ milspec rounds due to their lack of expansion (thank you Geneva and Hague conventions for taking common sense out of munitions) I would personally recommend a 55 to 62 grain ballistic tip (Barnes X for example) fired from a 16 to 20" barrel with a 1 in 7 to a 1 in 9 twist rate.

I personally use a 16" American Spirit Arms barrel with a 1 in 7 twist and get sub MOA accuracy with a 62 grain Barnes X tipped round. I do use milspec for plinking, but for defense it is the Barnes. I also use the equivalent 155 grain round in my .308 fudd gun. For my handguns, I like the Hornady critical defense which is the pistol caliber equivalent.

I am old school when it comes to weapons. Specific round for specific purpose for specific weapon. Fudd gun for extreme range, AR to 300 yards (but will go further for varmint hunting) and 45ACP for carry. Of course it is a 1911.

Much of bullet performance isn't just velocity and mass, it's bullet design. You choose well with the Barnes bullet (one of the better choices). Being able to penetrate deep enough with the maximum amount of weight retention is critical to effective fatal shots.

The Geneva convention has nothing to do with hollow points. It's the Hague Convention. There are ways around it for SOF troops but will not discuss that here.

My chronograph shows I get right @ 2500'fps at the muzzle with my 11" SBR. That gives me equal performance @310 meters as the same round in an 18" barrel @ 400m. Not really that much difference. Effective kills have been made @400m with the 5.56 platform. If I used some of the powders that we can't buy on the street, I'd get about 100 more fps.

So if I can carry an 11" gun (vs a 16" gun), put a suppressor or it and gain fps and have minimal sound/muzzle signature, I'll take the SBR any day.

The Reaper
06-20-2013, 18:56
Some of the issues with short barrel rifles (or AR pistols) make them pretty much useless in the real world. Although, as previously posted, a VSBR or SBR may be appropriate for vehicular operations with close proximity targets, typically, anything below a 16" barrel will cause performance degradation. Lower velocity due to incomplete burning of the powder, excessive flash and greater stress on the operating system due to gas pressures in a shorter system.

The round (cartridge) is designed to give the best performance when all powder is burned and gas expansion is maximized as the bullet reaches the muzzle. Designing a round for 5 grains of powder when the barrel is only long enough to have burned 4 grains before the bullet exits the barrel would be fruitless. You would have to go to a faster burning powder in order to reach proper pressures at the muzzle. But, then you face the issue of excessive chamber pressures. Over pressurize the chamber and you have problems ranging from case separation to blown primers to outright explosions. Also, driving the bullet too fast from the chamber can cause excessive skipping of the round before the rifling can catch. This reduces accuracy by imparting inadequate spin to stabilize the bullet.

We see/hear a lot about ballistics. Too many people only know about external ballistics which is what the bullet does in the air. But, we must also consider internal ballistics which is what happens between the primer strike and the bullet leaving the muzzle. Also, and IMHO the most important is terminal ballistics. What happens upon impact. Does it have enough velocity to allow for full expansion at the vitals of the specific target or does it have too little or too much? Would you use a round designed for a 200lb man to kill rabbits? Would you use a varmint round on a man? Although with proper placement, either of these rounds could be made effective, they are not interchangeable.

Excluding FMJ milspec rounds due to their lack of expansion (thank you Geneva and Hague conventions for taking common sense out of munitions) I would personally recommend a 55 to 62 grain ballistic tip (Barnes X for example) fired from a 16 to 20" barrel with a 1 in 7 to a 1 in 9 twist rate.

I personally use a 16" American Spirit Arms barrel with a 1 in 7 twist and get sub MOA accuracy with a 62 grain Barnes X tipped round. I do use milspec for plinking, but for defense it is the Barnes. I also use the equivalent 155 grain round in my .308 fudd gun. For my handguns, I like the Hornady critical defense which is the pistol caliber equivalent.

I am old school when it comes to weapons. Specific round for specific purpose for specific weapon. Fudd gun for extreme range, AR to 300 yards (but will go further for varmint hunting) and 45ACP for carry. Of course it is a 1911.

Mental:

This has been pretty well flogged here before, if you want to do some searching and reading.

TR

The_Mentalist
06-22-2013, 09:36
Much of bullet performance isn't just velocity and mass, it's bullet design. You choose well with the Barnes bullet (one of the better choices). Being able to penetrate deep enough with the maximum amount of weight retention is critical to effective fatal shots.

The Geneva convention has nothing to do with hollow points. It's the Hague Convention. There are ways around it for SOF troops but will not discuss that here.

My chronograph shows I get right @ 2500'fps at the muzzle with my 11" SBR. That gives me equal performance @310 meters as the same round in an 18" barrel @ 400m. Not really that much difference. Effective kills have been made @400m with the 5.56 platform. If I used some of the powders that we can't buy on the street, I'd get about 100 more fps.

So if I can carry an 11" gun (vs a 16" gun), put a suppressor or it and gain fps and have minimal sound/muzzle signature, I'll take the SBR any day.
Which gas system are you using? A carbine length system could increase MV over one set for a VSBR by extending the point at which the gasses are vented to cycle the bcg. Then again, there are so many different mods coming out that a great part of my data is out of date.

Also, I did include The Hague conventions in the munitions issue. Not arguing just saying.

Reaper, my apologies if I mentioned something previously mentioned but was just trying to follow along in this particular thread and had no intention of rehashing things. I did "browse" quite a bit and primarily in this section before I made my first post. Sorry if I missed it. Trying hard to comply with policies here.

Sinister
06-27-2013, 18:21
Short Colt Commandos (both modern and the XM-177 family), the Mark 18, and the Para-Commando SAW are all the rage because they're short. They almost scream, "Look at me -- I'm special!"

As discussed, they have a place if that's your mission or the mission calls for them.

It doesn't hurt if you're surrounded by guys with longer-reach and heavier weapons, tasked to watch your back and flanks.

M193 and M855 aren't perfect and both have their faults and limits. They're issued and generally available.

While there's been LOTS of talk about how a projo MUST fragment to create wounds to kill people (especially on peripheral hits), if you hit someone in the Central Nervous System (center of the grape or through the spine) you can knock the knucklehead down and make him floppy faster than waiting for the air and blood to leak out slowly.

Hit the bad guy, hit him a lot, in the center, early and often. Simple. Does it really matter what gun it is, and what's bolted on the rails?

I've never been issued the ideal weapon. At one time I had a dozen individual weapons cards for stuff I COULD use if the mission called for it.

JMonty
11-06-2013, 15:39
:lifter
Hit the bad guy, hit him a lot, in the center, early and often. Simple. Does it really matter what gun it is, and what's bolted on the rails?

That's an idea.

kgoerz
11-06-2013, 15:45
Can't remember the exact velocity. But when I was a fed we Chronographed a bunch of different stuff thru our 10" barrels. The winner was Federal 77 grain HP. I remember when the Army first issued the M4 to the Infantry in mass. My first thought was did they change the Ammo. Answer was no. It was right around Faluija. Reg Army guys were begging SF for Ammo. Marines went back to their 21" AR'S.

Max_Tab
11-12-2013, 12:37
Some of the issues with short barrel rifles (or AR pistols) make them pretty much useless in the real world. Although, as previously posted, a VSBR or SBR may be appropriate for vehicular operations with close proximity targets, typically, anything below a 16" barrel will cause performance degradation. Lower velocity due to incomplete burning of the powder, excessive flash and greater stress on the operating system due to gas pressures in a shorter system.

This is why I'm contemplating the .300 Blackout. It was designed to burn all the powder in the cartridge, at 9 inches.

I saw some old post's talking about the .300, anyone got some experience with it yet? (if I missed a thread talking about it, sorry)

The Reaper
11-12-2013, 13:22
This is why I'm contemplating the .300 Blackout. It was designed to burn all the powder in the cartridge, at 9 inches.

I saw some old post's talking about the .300, anyone got some experience with it yet? (if I missed a thread talking about it, sorry)

I like it.

TR

koz
11-12-2013, 14:11
This is why I'm contemplating the .300 Blackout. It was designed to burn all the powder in the cartridge, at 9 inches.

I saw some old post's talking about the .300, anyone got some experience with it yet? (if I missed a thread talking about it, sorry)

I agree with TR. It's a cool round. I've got the 10" barrel. There are a lot of reloading and factory options from supersonic to subsonic. Southwest Ammo had subs in stock pretty recently. Barnes has made some specific bullets for it (expanding at certain velocities). You can also use 5.56 brass to make 300BLK, it just takes some effort. The thing I like the most is it only takes an upper change. Same BCG (bolt face), same magazines, etc…

Peregrino
11-12-2013, 20:06
I like it. Mine's a 16" barrel with a carbine gas system and required some initial tweaking. It now shoots 125s, 147s and 220s (all I've experimented with) just fine. I do need to get the right optics for it though. The current EoTech is OK but it doesn't maximize the potential.