View Full Version : 6.5 Grendel Project

03-24-2015, 08:52
A couple weeks ago, a HS friend ask for some help building his 1st AR.

I am bored and have persistent FABG, and this is a bad combo.

I have wanted an upper that spanned the gap between 5.56 to 50 Beowulf.

I spent 2 minutes looking at the AR10 7.62 route and just didn't get a warm fuzzy, besides I wanted to share one of my AR lowers.

Looked at the 7.62x39,, WHY when I have a good AK??

Looked at the 300 Blackout. It's a 30-30 squeezed into an AR.

That left the 6.8 SPC & 6.5 Grendel. Both are about the same, but I have a AA lower.

Used my google-foo on the various gun sites and have collected most all the parts.

AA Grendel upper
AA bolt
AA barrel, started at 22, cut to 17, sold @ good price.
Seekins SP3R keymod hand guard
misc bits, gas block, tube, carrier, etc

In the process I ran into another QP that has taken a shine to the 6.5..

REF: FAGB - FOG Addicted to Gun Buying

PS: In looking at the 300 blackout, I was tweaked by the fact that it is supported by sub-sonic factory ammo for use with a can.

Knowing that at best, it's a 30-30, I looked up the ballistics tables and looked for a comparable round.

The 300 Blackout in sub-sonic mode is equivalent to the Army .30 cal, M1 carbine, one of the most anemic rounds ever created.

tom kelly
03-24-2015, 14:56
Is the ammo hard to get? what about the cost/round/ Tom Kelly

03-24-2015, 15:14
Is the ammo hard to get? what about the cost/round/ Tom Kelly

Ammo is running around 1USD @ round delivered. You may get if locally a little cheaper. Seems to be plenty.

Wolf is also making 6.5 in steel and brass case. The steel is typical, but I understand the brass is fair. Not a 600yd tack driver, but fine for hunting.. There was an early problem with over sized primer pockets, but I think it is fixed.

I use this site, plus the normal sources for ammo. It doesn't report "no stock" but gives you an idea of what to expect.

6.5 Grendel @ .87 each
6.8 SPC run .83 each
.308 @ .50 each
5.56 @ .35 each

Most of those using it for long range, reload.
Then factor in s&h


There is a QP here that shoots 6.5 matches, might stop by??

03-24-2015, 15:15
Hornady makes some ammo as well as Wolf (not great but ok for getting on paper). Alexander Arms makes some which is excellent. It's a nice round.

I've got some good loads using the Barnes TSX/TTSX bullets. Mark Larue killed a nice elk @ 460~ yards with a 6.5G.

03-24-2015, 15:42
Hornady makes some ammo as well as Wolf (not great but ok for getting on paper). Alexander Arms makes some which is excellent. It's a nice round.

I've got some good loads using the Barnes TSX/TTSX bullets. Mark Larue killed a nice elk @ 460~ yards with a 6.5G.

Hornady, 300 rds in the air..

My quandary, I don't need a 600 yd tac-driver. Will be shooting mostly at the range.

I'm trying to get my head(pocketbook) around a new scope.

All mine are low X deer, shotgun, pistol, or red dot, with the exception of the 6x24 on my pellet gun.

I think I need something in the 3x9 or 4x12 range, but need to keep the budget reasonable.

Unlike some of the pro level QP's, I am not looking at scopes that start with a N, S-B, or V and end in a lot of zero's.. :lifter

Additionally, Because of the "bull" barrel, this build is sitting just short of 8lbs. I don't want wheels on the bipod..

Currently, I am looking at the Leupold AR series. Anyone with an opinion??


The Reaper
03-24-2015, 16:18
I like the .300 AAC Blackout for its flexibility and ability to shoot everything from 110 gr. to 250 gr. .30 bullets and the ability to shoot suppressed.

I liked it when JD Jones was loading it as the .300 Whisper.

The heavy subsonic .300 Blackout rounds are basically very improved .45 ACP rounds, with a high BC 240 gr. bullet at 1000 fps. If you think it is ballistically inefficient, compare it to the 6.5 gr. bullets at the same subsonic velocity.

With the lighter bullets, like the 110s and 120s, it roughly 90% of a .30-30 or a 7.62x39. The Barnes TSX bullets are great hunting rounds.

It is not bad with 147 gr. surplus M80 ball bullets, which are easy to find and very inexpensive.

I can resize and make .300 BO cases out of 5.56 or .223 cases, which are relatively cheap as well.

.300 BO is expensive to buy reloaded, but if you make / reload your own brass and use the inexpensive plinking bullets, you can shoot it for less than 40 cents per round.

Overall, it is a great way to fit a .30 round into an AR-15 action.

I also like the 6.5 Grendel (and the .260, the 6.5 Creedmore, and the original 6.5x55), but as my gunsmith says, the Grendel will not do what most people expect it to. He says that there is inadequate room in the case for the powder it needs to run. He also said it is almost impossible to get the velocities that most people think it will give, and the effective range then suffers, leading to disappointment

FWIW, I have shot the Grendel, the 6.8, and the .300 Whisper and Blackout.

As far as scopes go, you usually get pretty much what you paid for. Buy a cheap scope, don't expect it to shoot well, or for every long. As a general rule of thumb, the scope should cost at least as much as the rifle under it.

Just my .02, YMMV.


03-24-2015, 16:19
Not to adds confusion but have you looked at the 260 rem. You have to use the AR10 lower and upper but the performance is better and you get the 6.5 performance with the 140gr and its great BC

I seriously looked at going the AR10 route, and wold have looked at the different cals available. But decided on sticking to the 5.56 platform.

This build has been brewing for 2yrs.. 2yrs = 2 minutes in my decision process.

03-24-2015, 16:51

I was looking at the 300bk from the point of the a suppressor. Not as a comparison to the 6.5G down range. And speaking of suppression, any of the good brand cans will bring the noise to acceptable levels. So, I took sub-sonic ammo off the table.

The fact that I don't re-load also played into the decision.

The 6.5G fills a gap, and allows me to use my other AR lowers.

I am sure most are aware of the different AR frame rounds, but here is a chart with some numbers for those that don't.

Again, I don't reload, so I use published factory load data..

The Reaper
03-24-2015, 17:58
I have spent some time shooting .30 suppressed and unsuppressed, supersonic and subsonic.

The can will not make the round subsonic.

The sound difference between subsonic and supersonic, even if both are suppressed, is significant.

If you don't reload, the difference in cost is not as important, but I do reload and the 6.5 Grendel cases and bullets are significantly more expensive than the .300.

It does indeed, fill a gap.

Pull your chronograph out when you get it running and let us know how close you come to the published velocity numbers.


03-24-2015, 19:40
I got the 6.5G as a hunting rifle that was lightweight. It will do well with deer, hogs, coyotes, etc..

I love the 300BLK round for a multipurpose round. Look at the Sig MCX. It should replace all Sub-guns. (Think MP5SD, UMP, 9mmSMG) Use the Lehigh 194gr bullets that are subsonic but have great expansion when you want very quiet and low penetration. Then if you need to step up to a rifle round to get on/off target - think Iraq / Somalia, etc.. Put the 110gr TAC-X (Barnes) and you've got an awesome round. The Sig has a 8" barrel then add the suppressor. Not much bigger than the MP5SD.

I've killed a lot of deer & hogs with my 300BLK.

As far as suppressors making the round go sub - there are a few barrels (MP5SD, some integrally suppressed .22's) that are ported before the suppressor to drop the velocity to subsonic. But the round has to be around the 1070-1300fps mark to drop it below supersonic. It's not the suppressor, it's the ported barrel.

A supersonic round (5.56/308/300WM) even suppressed will have a significant noise signature from the supersonic crack. An AR platform will usually have more noise at the shooter's ear than the muzzle due to gas coming out during cycling. There are suppressor companies that are working to reduce the back pressure but the supersonic crack is something you can't get rid of.

You can do a subsonic 308 load (180/190gr bullet with Trailboss powder) It's safe as that powder is really high volume (I use 10.7gr with no filler) But even then, you still have more noise than the 300BLK. I think it's more gas due to more powder burn.

03-25-2015, 03:09
Thanks for the info guys.

I plan to use the can for only one purpose.. To protect my ears, as such I am more concerned with the noise levels at the bench.

I have watched dozens of ******* videos of can tests, made by bubba's with more money than brains. But Silencerco and a couple other of the name brands have some good comparisons.

Granted, They recorded at Their facilities, on Their equipment, using Their gear.

Then I play it on My puter, with My speakers, and listen with My moderately failing ears..

What can go wrong??? :munchin

PS: The fact that u's guys have access to ALL THE TOYS, does leave me jealous to a hi-level.. :D

03-25-2015, 08:43
Before you choose Silencerco, you should look at other options. I've got a couple of their cans, and they do make a nice product but some of their braintrust has left (or better way to describe - guy sold the company but was to stay on as an employee then after about a year, was given walking papers - much like the AAC saga. Ironically most of the AAC guys have ended up at Sig and they are releasing a bunch of new cans). This was with both the Silencerco and SWR co-founders.

A couple cans to look at

ThunderBeast Ultra Series. (Particularly the Ultra-7). It's a mid size can and can take a lot of abuse for a lightweight can. Very accurate / low POI shift.

OSS - one of our own (and PS member) works here. They have completely re-thought the suppressor concept.

Dead Air Armament - This is Mike Pappas (formerly from Silencerco - guy who came up with most of their product line) new company. Sandman-S

Sig - With Kevin Brittingham (AAC founder), Lindsey Bunch (1st SFG/ USASOC) and now John Hollister (AAC) on board, they will have some nice things coming out.

Remember the MSRP is not what you should pay.

03-27-2015, 04:39
It's about complete, but only dry-fit.

I need to get the barrel threaded before I clamp all the bits down.

Put this puppy on the scale,, just a tad over 8lbs (17.6K).. :eek:

The factory AA barrel is like a kettle-ball. The rest of the bits are + or - normal weights. Not complaining, might actually help at the bench?

On a parallel effort, I am looking at scope options. Something in the 3-9x40 to 4.5-14-40 range. Leupold VX- 3 or III or AR lines. I liked the Vortex Viper line, but they are consistently 20-30 % heaver than the Leupold's.

I would like a 1st focal plane reticle, but at this end of the scale most all are 2nd focal plane. The 1st would be visually nice, as the reticle doesn't shrink as the magnification increases. FOG's need help with old eyes. As I am not looking at competition, I can probably be satisfied with the later.

04-09-2015, 11:27

The barrel is at the shop getting threaded. Should be back next week.

In the mean time, I did some home work and settled on a scope choice(s). Actually several..

For brand I chose Leupold, for all the standard reasons. Looked at Vortex, Sightmark, Steiner, Zeiss, Trijicon....

Within the Leupold's were the VX-3 (1inch) and VX-R (30mm,firedot). In my not to scientific match-up, the VX-3 had better eye relief, twilight vision, lighter.

For power I looked for something in the 10x to 16x mag. I looked at a lot of scope pics "at the range" and at 300 yds a 6x is good for minute of man,, maybe a bit better,, so I X'd the 3-9 power. With my eyes I decided to go higher.

Price range under 1K, using ebay, I managed to get 35% off retail new, store demo, w/full warranty.

Mount? LaRue is not the only one out there, but it is available, with discount, if you hunt.. The others: Leupold, Warne, GG&G, & ADM.

Delivered today: Leupold, VX-3, 66430, Duplex, 4.5-14x40 & LaRue SPR LT-104

Examples: 300yds, 24x, 12x, 6x

The Reaper
04-09-2015, 15:29
Very nice.

Hey, how did you get 24x out of a 14x scope?


04-09-2015, 15:50
Very nice.

Hey, how did you get 24x out of a 14x scope?



The pics I google foo'd in my search for info.

Finding a set of comparative pics that had both magnification and distance was a bear. There are thousands of pics, but most are not labeled.

People also have a tendency to aim at non-targets. You can't judge size looking at you neighbors back door handle..

Most of the good pics were from snipershide forum, lots of long range shooting. But even there, they posted a lot of 32x++ @ 1K which is not easy to "down size" to something useful.

Here are a 14x @ 900 yds. It tells me, if I don't shake to much, I can see a man size target.

04-09-2015, 17:15
Very nice.

Hey, how did you get 24x out of a 14x scope?