308 AR10 Build Info/Picture Thread

[PotatoeTactical]

Receiver: ZEV LFAR lego set

Barrel: Shilen 20” barrel 1:9 twist

Bolt and Carrier: Shilen matching High pressure bolt, Lantac Enhanced carrier

Gas block: handmade adjustable gas block I did at work

Handguard: SLR rifleworks quad rail for that sexy M110 vibe

Trigger and controls: Geissele SSA-X trigger, Geissele controls and Radian Charging handle, Geissele Single side 90* selector.

Grips: Running between a local shops 90* grip and some random sand impregnated grip I got for cheap.

Glass and Mount(s): Kahles 624I and ADM 0moa mount, 45* warne topped with an ElCheapo Holosun I had left over from an SBR build. Considering an Acro or RMR piggy backed in ADMs M-Brace mount. Griffin Armament rear peep battle sight and Midwest HK fixed front.

Leg Spreaders: GG&G bipod from years ago.

Muzzle: Made in ID can I made for my 300RUM/30-378wthby before the barrels got torched. Looking into Allen Engineering M5-.30 with SPR mount or an AB Raptor 10 stack.

Figured it’d be a cool match to my dads Knights SR25 from the early 00’s.

 

[TJC0572]

Finally finished, almost.

 

[MSTN]

Just finished hammering together another really nice 6.5CM: Seekins SP10 Builder's Kit, done up in Accuracy Int'l Dark Earth Cerakote; Rock Creek 5R SS barrel by Craddock Precision; SLR adjustable gas block; JP FMOS bolt carrier group; JP H2 Silent Captured Spring Kit. I thought I'd see if it wanted to be a shooter, so I threw a scope on it. With no gas system tuning at all, groups were immediately sub-MOA with the first box of factory ammo I picked up.

 

[AMGtuned]

Here's my "twins". AR10 and 15, both Aero sets and handguards. More fun to shoot than they were to build.
View attachment 7063155

Bumping my old post, because I found this video on my phone, and uploaded it to YT.



12:00 wind was brutal. There's a plate at 525 that you can hear get smacked if you crank it. Can is the F1 I built for my 26" 300wm.

 

[WI2017]

SP-10 got some time out of the safe today

 

[Jsp556]

Optics planet has some 18” Lothar Walther 308 barrels for $347, free shipping.

 

[GhostFace]

That's a helluva deal, they're aroubd $600 from LW now...

 

[mjh30]

Still a work in progress, just aero upper/lower, prs gen 3, trigger tech for trigger, jp bolt, lmos carrier, silent capture spring, sentry 8 gas block, nos proof 22 plus 2. Caliber is 260, basically its what caliber I shoot, so I went with it, kac and asc mags help with coal. Showing some promise.

 

[TJC0572]

^^^ Nice set up.

 

[stormhammer]

A fun build. Right now I have a BA 16" 308 barrel to go in, but debating on just making it more ridiculous and putting a 16" 6.5CM instead.

 

[jLorenzo]

What kind of buffer would be best for the widest variety of ammo?

 

[rpoL98]

What kind of buffer would be best for the widest variety of ammo?

adjustable gas block.

best buffer weight (if that's what you're asking) will be determined by your barrel characteristics (length, gas length), the interaction of your gas port size and your buffer spring. and whether you're always suppressed, sometimes suppressed, or never suppressed.

ignoring for the moment the suppressed consideration, you'd want your buffer weight sized so that with your weakest oomph ammo, your gas block wide open, that your rifle still cycles: last-round bolt hold-open, lock back on empty.

or maybe I misunderstood your question.

 

[Trumpinator]

Added a few things to the AR10 today. A Magpul D50 drum(you know for fast moving deer), Harris BRM mlok bipod (13oz), and a Aero VG6 Epsilon Brake. Cant wait to take it to the range.

 

[jLorenzo]

adjustable gas block.

best buffer weight (if that's what you're asking) will be determined by your barrel characteristics (length, gas length), the interaction of your gas port size and your buffer spring. and whether you're always suppressed, sometimes suppressed, or never suppressed.

ignoring for the moment the suppressed consideration, you'd want your buffer weight sized so that with your weakest oomph ammo, your gas block wide open, that your rifle still cycles: last-round bolt hold-open, lock back on empty.

or maybe I misunderstood your question.

Thanks, I will be going with an adjustable gas block, no can for now but would like one. I have been eyeing the Odin works adjustable buffer but maybe I should just go with a basic 308 carbine buffer and see how that goes. I would like to use a 6.5 upper and a 308 upper on the same lower if I can. If not I'll get another lower down the road. I would run 147-155gr with the 308 either 18" or 20", rifle length gas and 120,130 and maybe 140gr with the 6.5 probably 22" with as long a gas tube as I can get. Mostly handloads.

 

[45-90]

Just finished an AR 10 in 338 Ruger Compact Magnum, with 18" fluted barrel.
7 lbs 11oz, no optic.

 

[Sigmanx]

Just finished an AR 10 in 338 Ruger Compact Magnum, with 18" fluted barrel.
7 lbs 11oz, no optic.

That’s pretty interesting. How hard is it to find ammo for that?

 

[45-90]

That’s pretty interesting. How hard is it to find ammo for that?

Ya, probably don't...I didn't see any locally.

But don't let that bother ya...it's easy to neck up 6.5 PRC brass, and I found that available.

I button bump the 6.5 PRC up with a homemade mandrel in one step from .264 original dia to .284, to .308, .338 in one pass.
Then run through the FL sizer, and skim neck turn to the sholder, and anneal.

 

[Cascade Hemi]

What kind of buffer would be best for the widest variety of ammo?

This is a trick question. How good or bad do you want your rifle to shoot? Most AR's are over gassed to function with the widest variety of ammo. If you narrow down your ammo selection you can tune the gun to function with the least gas and reciprocating mass for your environment. Or you can add tons of weight and gas. It's your choice.

FWIW, 16" and 18" RLGS barrels with LMOS BCG and a 1.7oz buffer feel pretty good.

 

[jLorenzo]

Can anyone speak to 16 vs 18 vs 20 for a 308? I am torn on which way to go, Was thinking 20 but then if I build another 6.5 upper with a 22 or something like that I might as well go shorter for the 308. So then maybe 18 or 16, I have heard 18 is needed to burn all the powder?

 

[jLorenzo]

This is a trick question. How good or bad do you want your rifle to shoot? Most AR's are over gassed to function with the widest variety of ammo. If you narrow down your ammo selection you can tune the gun to function with the least gas and reciprocating mass for your environment. Or you can add tons of weight and gas. It's your choice.

FWIW, 16" and 18" RLGS barrels with LMOS BCG and a 1.7oz buffer feel pretty good.

I like smooth and will be shooting handloads of likely all the same bullet. 155 smks maybe blast with some 147 ball.

 

[jLorenzo]

Added a few things to the AR10 today. A Magpul D50 drum(you know for fast moving deer), Harris BRM mlok bipod (13oz), and a Aero VG6 Epsilon Brake. Cant wait to take it to the range.

View attachment 8391709
View attachment 8391710
View attachment 8391712

Nice green. How do you like that brake? How are you mounting that bipod.

 

[PotatoeTactical]

I like smooth and will be shooting handloads of likely all the same bullet. 155 smks maybe blast with some 147 ball.

Running them light bullets, I’d say a 13.7-16 would be perfect if you just want another rifle thats easier to pack/move. Velocity in the 16” will still give good performance with sub 165gr pills, dependent on powder itll be 16-20 inch for full powder burn, most common will be 16-17” for full burn. If your goal isn’t super long or pushing fps, the 16 will do everything you’ll need. I personally love 20s cause its what I like, no real reason other than it “looks” right with a 20.

Basically, if recoil/smooth is what you want then the longer your gas system the smoother it’ll be. Ive seen and shot a few peoples who run rifle length gas systems on 16-16.5” rifles and they were pretty smooth. My 20” with a +1 rifle is smooth. Gas port size, adjustable gas block (sometimes several different variants), buffer weight and spring are all factors to consider. Especially in LFARs.

 

[Sigmanx]

Can anyone speak to 16 vs 18 vs 20 for a 308? I am torn on which way to go, Was thinking 20 but then if I build another 6.5 upper with a 22 or something like that I might as well go shorter for the 308. So then maybe 18 or 16, I have heard 18 is needed to burn all the powder?

If you think there’s a good chance you’ll end doing a 6.5 upper then you should definitely look into 16”-18” got the 308. 18” is still gonna be good for around 1k. 16” will do 800 yards comfortably all day long.

 

[jLorenzo]

Anyone have experience with Criterion? Considering one those for the 308, if I can get close to a minute with handloads I'll be happy. Might go Krieger for the 6.5 though.

 

[45-90]

Different barrels of the same length have different velocities with the same load.
I have a fast 16" 308 that runs very close 10 to 15 fps the same velocity as one of my 18" barrels.
Doubt that is very common, should be 40 to 50 fps difference.
Heard the 308 burns all the powder in 16, 18 or 20 inch barrels? ...not hardly. That's totally false. My 30" 308 keeps gaining speed over the shorter barrels including the 27".

 

[TonyTheTiger]

Different barrels of the same length have different velocities with the same load.

A difficult concept for many to grasp.

 

[jLorenzo]

I am not sure if some of these comments are aimed at me, I am not concerned with velocity much at all. This is a shorter barrel 308 gas gun. I will be banging steel out to 1k at the most. My concerns are more with blast and handiness. I don't think 16 vs. 18 will make almost any difference other than the 18 might be a touch heavier and have a little less blast. 20 might be even better but if I did want to do some off hand stuff it might be a bit hefty. 16 does look cool.

 

[45-90]

I am not sure if some of these comments are aimed at me, I am not concerned with velocity much at all. This is a shorter barrel 308 gas gun. I will be banging steel out to 1k at the most. My concerns are more with blast and handiness. I don't think 16 vs. 18 will make almost any difference other than the 18 might be a touch heavier and have a little less blast. 20 might be even better but if I did want to do some off hand stuff it might be a bit hefty. 16 does look cool.

You should be concerned about velocity if you're shooting 1000yds, and just about everything else, as consistent velocity is important.
Cool looking, should be of less concern as performance.
But you can have light AR 10 308 with pormance if your into handloading and building your own rifle.
I set up a 6 lb 3 oz 16" fluted barrel, with titanium bolt carrier, and muzzle brake.
With carbon fiber handguard and magnesium upper.
7 lbs 12 oz with scope fully set up for 1200 yds. Running 168 eldm at 2756 fps with .5" 5 shot groups, with cheap LC military brass...this is a fast 16" barrel, velocities are slighty less than the 18", from 150 gr to 208 gr.
Whether it looks cool, is up to tbe person looking at it, but also being functional is much more important.

A complete magnesium upper or rifle can be had at ROAM, but with a pencil barrel, it's under 6 lbs,... if interested in light 308.

 

[TonyTheTiger]

A difficult concept for many to grasp.

I am not sure if some of these comments are aimed at me, I am not concerned with velocity much at all.

That's not what I was getting at. I just see tons of silly posts where people tie an exact velocity to a given barrel length and believe it applies across the board.

 

[jLorenzo]

You should be concerned about velocity if you're shooting 1000yds, and just about everything else, as consistent velocity is important.
Cool looking, should be of less concern as performance.
But you can have light AR 10 308 with pormance if your into handloading and building your own rifle.
I set up a 6 lb 3 oz 16" fluted barrel, with titanium bolt carrier, and muzzle brake.
With carbon fiber handguard and magnesium upper.
7 lbs 12 oz with scope fully set up for 1200 yds. Running 168 eldm at 2756 fps with .5" 5 shot groups, with cheap LC military brass...this is a fast 16" barrel, velocities are slighty less than the 18", from 150 gr to 208 gr.
Whether it looks cool, is up to tbe person looking at it, but also being functional is much more important.

A complete magnesium upper or rifle can be had at ROAM, but with a pencil barrel, it's under 6 lbs,... if interested in light 308.

Too light for me. I would be looking for more weight shooting off a bipod most of the time. Would be cool to carry though. I shoot a 20" bolt gun 308 at 1000 to satisfactory level for what I am doing. 308 at 1k is already sub optimal IMO. If I can reliably hit a IPSC I'm ok.

How did you achieve those speeds with that bullet out of a 16? How long does brass last?

 

[rpoL98]

build pic thread:
Criterion 308 barrel, Aero build.

Faxon 6.5CM:

 

[45-90]

Too light for me. I would be looking for more weight shooting off a bipod most of the time. Would be cool to carry though. I shoot a 20" bolt gun 308 at 1000 to satisfactory level for what I am doing. 308 at 1k is already sub optimal IMO. If I can reliably hit a IPSC I'm ok.

How did you achieve those speeds with that bullet out of a 16? How long does brass last?

Shoot what is right for you.
I have 308s with 16" to 30" barrels and twist rates from 12 to 8 twist. Light to heavy weight firearms.

It's primed Lake City brass so who cares, I have thousands more for AR service. Most have held up well as they've been through the primer swage and checked.
I buy them in 1000 piece lots, load em on one the Dillion progressive.
I do sometimes use Lapua in AR 10s like in the 6.5 CM.
But not for the 308 AR 10, they are accurate with the LC brass. And it's no big deal to lose a few cases.
The load is in the manual

 

[Sigmanx]

What are y’all’s thoughts on choosing between the Faxon match series 20” vs the Criterion 20” Hybrid w/LR118 match chamber. I’m leaning towards the Criterion w/ the headspaced Fulton BCG option.

 

[Sigmanx]

Anyone have experience with Criterion? Considering one those for the 308, if I can get close to a minute with handloads I'll be happy. Might go Krieger for the 6.5 though.

I’ve been looking at either the Criterion 20” Hybrid 308 or the Faxon 20” Match heavy fluted. I’m not sure if the 5R rifling in the Faxon is going to be of any help to performance or not.

 

[TonyTheTiger]

What are y’all’s thoughts on choosing between the Faxon match series 20” vs the Criterion 20” Hybrid w/LR118 match chamber. I’m leaning towards the Criterion w/ the headspaced Fulton BCG option.

I've had bad enough luck with Faxon that I wouldn't recommend them for an accuracy build. I'm sure others have better experiences with them, but it really left a bad taste in my mouth.

 

[Sigmanx]

I've had bad enough luck with Faxon that I wouldn't recommend them for an accuracy build. I'm sure others have better experiences with them, but it really left a bad taste in my mouth.

Definitely understand the sentiments. I’ve generally heard good things about them, but no company is free from lemons!

 

[jLorenzo]

Shoot what is right for you.
I have 308s with 16" to 30" barrels and twist rates from 12 to 8 twist. Light to heavy weight firearms.

It's primed Lake City brass so who cares, I have thousands more for AR service. Most have held up well as they've been through the primer swage and checked.
I buy them in 1000 piece lots, load em on one the Dillion progressive.
I do sometimes use Lapua in AR 10s like in the 6.5 CM.
But not for the 308 AR 10, they are accurate with the LC brass. And it's no big deal to lose a few cases.
The load is in the manual

Sweet. That is my thought as well going with 308 in the gasser. I have huge bags of brass. Gotta love LC. Any full pics of that light weight gun? I have seen someone with the 168 ELD do pretty well at 1k. Do you notice a big real world difference in performance and shootability between the 16 and 20"?

 

[jLorenzo]

What are y’all’s thoughts on choosing between the Faxon match series 20” vs the Criterion 20” Hybrid w/LR118 match chamber. I’m leaning towards the Criterion w/ the headspaced Fulton BCG option.

I don't have any experience with either of those but I have learned more and more, its worth it to spend the extra cash on the nicer stuff if you can. Often you will save $ not having to replace something that sucks later.

Although it depends if its worth to you. Building an Ar10 isn't really cheap by any standard so you might as well build as nice a rifle as you can. I've never regretted getting the nicer option after having it for awhile.

 

[jLorenzo]

build pic thread:
Criterion 308 barrel, Aero build.

View attachment 8398280


Faxon 6.5CM:

View attachment 8398292

Sweet. How do you like that Aero handguard?

 

[Sigmanx]

I don't have any experience with either of those but I have learned more and more, its worth it to spend the extra cash on the nicer stuff if you can. Often you will save $ not having to replace something that sucks later.

Although it depends if its worth to you. Building an Ar10 isn't really cheap by any standard so you might as well build as nice a rifle as you can. I've never regretted getting the nicer option after having it for awhile.

Definitely agree with that!

 

[jLorenzo]

Optics planet has some 18” Lothar Walther 308 barrels for $347, free shipping.

How do these shoot historically?

 

[45-90]

Sweet. That is my thought as well going with 308 in the gasser. I have huge bags of brass. Gotta love LC. Any full pics of that light weight gun? I have seen someone with the 168 ELD do pretty well at 1k. Do you notice a big real world difference in performance and shootability between the 16 and 20"?

This is the 6 lb 308, with a Leupold Mark4 M3, already zeroed for the 168 eldm at an average of 2756 fps.
I have more 308s than any other caliber, 8 at one time. Might be down to 6 or 7.
Barrels 16, 17, 20, 22, 24, 26, 27, & 30 inches. The 20", and the 26" were shot out at 8000 rds each. One 18" was taken off cause it did not preform well, and was a BA barrel. Replaced by a Proof barrel. Usually ya get what ya pay for, sometimes a cheap barrel will preform. But I believe you're better of spending at least mid price range for a barrel.
My light 16" is a shooter, with the 168 eldm, the newer 169 & 177 SMK.
But I also like the 18" Proof, in AR 10s I also have a 24" in the AR.
They are all easy to shoot, but for really long range it would be the 30" 8 twist shooting 230 Aips at 2620 fps.
I'm busy with other projects at this time.
A 6.5 twist 8.6 blackout bolt gun...and a 338 Ruger Compact Magnum for the AR 10 has just been chambered and assembled.
Loading for it now.

 

[jLorenzo]

This is the 6 lb 308, with a Leupold Mark4 M3, already zeroed for the 168 eldm at an average of 2756 fps.
I have more 308s than any other caliber, 8 at one time. Might be down to 6 or 7.
Barrels 16, 17, 20, 22, 24, 26, 27, & 30 inches. The 20", and the 26" were shot out at 8000 rds each. One 18" was taken off cause it did not preform well, and was a BA barrel. Replaced by a Proof barrel. Usually ya get what ya pay for, sometimes a cheap barrel will preform. But I believe you're better of spending at least mid price range for a barrel.
My light 16" is a shooter, with the 168 eldm, the newer 169 & 177 SMK.
But I also like the 18" Proof, in AR 10s I also have a 24" in the AR.
They are all easy to shoot, but for really long range it would be the 30" 8 twist shooting 230 Aips at 2620 fps.
I'm busy with other projects at this time.
A 6.5 twist 8.6 blackout bolt gun...and a 338 Ruger Compact Magnum for the AR 10 has just been chambered and assembled.
Loading for it now.

Sweet I like that scope for a gasser.

 

[jLorenzo]

Is there a difference between Armalite and DPMS barrels as far as fitting a upper receiver? Can I put a Armalite pattern barrel on a DPMS upper?

 

[45-90]

Is there a difference between Armalite and DPMS barrels as far as fitting a upper receiver? Can I put a Armalite pattern barrel on a DPMS upper?

They have a lot of differences, upper and lower reciever fit, bolt carreier group, will not headspace correctly, barrel nut, gas tube length, handguard, are different.
If you're talking just the barrel itself. I do not know, if the barrel extension is the same or has the same thread as the DPMS, incase it needed to be changed, and headspaced.
Check headspace with your guns bolt and a go gauge and a no go gauge, before installing....even then I don't believe the gas tubes are the same length...or interchangeable.
Easy answer, buy a new barrel.

 

[jLorenzo]

They have a lot of differences, upper and lower reciever fit, bolt carreier group, will not headspace correctly, barrel nut, gas tube length, handguard, are different.
If you're talking just the barrel itself. I do not know, if the barrel extension is the same or has the same thread as the DPMS, incase it needed to be changed, and headspaced.
Check headspace with your guns bolt and a go gauge and a no go gauge, before installing....even then I don't believe the gas tubes are the same length...or interchangeable.
Easy answer, buy a new barrel.

I do mean just the barrel. I am in the process of choosing a barrel.

 

[45-90]

I do mean just the barrel. I am in the process of choosing a barrel.

I believe the Armalite barrel will slip into the DPMS upper reciever, but you'd need an Armalite bolt to match, to get correct headspace, and the correct length gas tube.

 

[jLorenzo]

What do people think of X caliber barrels?

 

[TonyTheTiger]

What do people think of X caliber barrels?

I've got a couple in AR15's I've been happy with.

 

[jLorenzo]

I've got a couple in AR15's I've been happy with.

Closer to Krieger and Bartlein or closer to Criterion, BA and the like? How do they shoot?