LR-308 over gassed?

nadrepadre · June 29, 2017, 08:02 PM

Several years ago I picked up an LR-308 sportical with a 16'' barrel. I've switched over to a standard A2 stock and buffer which helped mitigate the recoil and violence of the action. But regardless of what I do, the recoil and shock transmitted through the rifle is pretty extreme. I've shot a lot of different loads through it and I can't get it to feel like some of the other 308 ARs I've shot. I intend to do mostly long range shooting and I'm thinking about going with a faxon or black hole weaponry 18'' or 20''. I'm wondering if DPMS might have made the gas port slightly larger to increase reliability with a wide range of ammo. Considered getting an adjustable gas block, but I'd rather have something I don't have to monkey with or worry about coming out of adjustment.

And before everyone gets up on their high horse declaring how terrible DPMS is, the rifle has been very reliable and functions %100. The AR platform gets accuracy from the trigger and barrel above almost all else. If I can shoot a 2'' group with 147 gr. ball that's all I need. Just wondering if other lr-308 owners have had similar experiences with over gassing.

ed308 · June 29, 2017, 08:12 PM

Almost all AR10 are overgassed. I have a Bushmaster AR10 in .308. I put a heavy buffer in mine and installed a muzzle break. Helped slow down the cycle plus reduced the recoil.

nadrepadre · June 29, 2017, 08:15 PM

Maybe a heavy buffer is the solution. Any recommendations?

Mobuck · June 29, 2017, 08:56 PM

Not to mount the "high horse" but I wouldn't even want a 16" .308. I have a 20" .308 bolt action carbine and it's about as obnoxious as I really care for. A 16" is NOT for me.
A 20" heavier contour barrel would help with the recoil and adjustable gas blocks aren't all that expensive these days.

ed308 · June 29, 2017, 09:01 PM

I put a Spikes H2 in mine. I used this muzzle break which really tamed the recoil. They have a black melonite finish.

http://www.ar15performance.com/inc/sdetail/2121/35900

nadrepadre · June 29, 2017, 09:10 PM

-Mobuck
I shoot a 7600 carbine in 30-06 all day and I love it. I'm not complaining about muzzle blast. When I said "high horse" I was referring to all the people who will inevitably start talking crap about DPMS because it's not a $2000 rifle. And do you think money is an issue when I'm talking about re-barreling this gun instead of getting an adjustable gas block? Did you even bother to read the thread?

Mobuck · June 30, 2017, 10:32 AM

"And do you think money is an issue when I'm talking about re-barreling this gun instead of getting an adjustable gas block? Did you even bother to read the thread?"
I didn't realize I made an issue of the cost.
" the recoil and shock transmitted through the rifle is pretty extreme."
I did mention that a heavier contour barrel would decrease the perceived recoil and that an adjustable gas block would address the "over-gassed" condition you mentioned in the header.
Did you want advice or not?

nadrepadre · June 30, 2017, 03:23 PM

Get off your high horse

It's pretty hard to convey and interpret what people say just through typing on a forum. I meant no offense.

salt and battery · July 1, 2017, 06:49 AM

Quote:

Originally Posted by Mobuck

Not to mount the "high horse" but I wouldn't even want a 16" .308. I have a 20" .308 bolt action carbine and it's about as obnoxious as I really care for. A 16" is NOT for me.
A 20" heavier contour barrel would help with the recoil and adjustable gas blocks aren't all that expensive these days.

yes a 308 with a 16" barrel it brutal in a bolt gun. in a semi auto it is worse

MarkCO · July 1, 2017, 09:30 AM

Yes, all .308 ARs are over-gassed. I have a 16" mid-length gas AR pattern .308 with a heavy .308 buffer and an adjustable gas block that is very pleasant to shoot. While not a fan of adjustable gas blocks, almost a necessity on .308 pattern ARs. I prefer the Superlative Arms. While I will not try to talk anyone into any particular barrel length, longer barrels with longer gas systems do help soften recoil impulses, but do not overcome the need for adjustable gas in the .308 pattern ARs.

Realize that, as opposed to .223/5.56, in .308 the commercial rounds have a higher pressure than the NATO rounds. Most ARs are set up still be reliable with the softest NATO rounds with some extra gas. That makes the commercial really overgassed.

Eod1 · July 12, 2017, 01:12 PM

Here is what you might want to do. I'm just telling you it worked for my guns. I have a 10 inch 308 pistol, 14 inch pistol, 16,20 and custom 28 inch rifle. If you have used all the buffers, springs and tubes for 308, tried the heavier carriers to get that weight to help slow the cycle down try a adjustable gas block. Brad out at Odin Works makes one I use. I can tune in the cyclic rate and slow the gun down. it works really nice on the pistols.

stagpanther · July 12, 2017, 04:22 PM

Quote:

But regardless of what I do, the recoil and shock transmitted through the rifle is pretty extreme

What does that mean? Are you only able to fire a few shots before your shoulder is sore from recoil? Is the BCG recoiling so hard that it's damaging parts of the gun? Is the gun jumping with muzzle flip so bad you have a hard time holding on to it?

ronl · July 13, 2017, 05:31 PM

My 16" CMMG CBR isn't brutal at all. The brake on mine works very well.

bfoosh006 · July 16, 2017, 03:07 PM

Heavy rifle length buffer.....

https://www.kakindustry.com/lr-308-p...e-buffer-heavy

Tubbs Flatwire .308 spring ...

https://www.midwayusa.com/product/98...tainless-steel

If those don't work out... then seriously consider an adjustable gas block.... Almost all .308 ar's are over gassed, I am going through the same thing.

The cyclic speed is WAY faster then needed ( or wanted )

One thing to remember... sometimes adding all that mass to the recoil cycle can be a step backwards ( muzzle dip from a super strong spring slamming all that mass into the breach face ) ... so personally I avoid excess strength springs.

marine6680 · July 16, 2017, 08:05 PM

So many AR pattern 308s are over gassed.

Even with a new barrel, and an 18in using rifle gas is about as low as I would go, it may not fix the problem fully.

My PSA when I first got it, was way over gassed. I had to use a steel 9mm buffer and added three tungsten weights, just to get it to not unlock/extract too quickly. A new 20in barrel reduced the issue, so I can use an H2 buffer... but I still want to get an adjustable gas block for it.

June 29, 2017, 08:02 PM	#1
nadrepadre Member Join Date: September 12, 2012 Posts: 27	LR-308 over gassed? Several years ago I picked up an LR-308 sportical with a 16'' barrel. I've switched over to a standard A2 stock and buffer which helped mitigate the recoil and violence of the action. But regardless of what I do, the recoil and shock transmitted through the rifle is pretty extreme. I've shot a lot of different loads through it and I can't get it to feel like some of the other 308 ARs I've shot. I intend to do mostly long range shooting and I'm thinking about going with a faxon or black hole weaponry 18'' or 20''. I'm wondering if DPMS might have made the gas port slightly larger to increase reliability with a wide range of ammo. Considered getting an adjustable gas block, but I'd rather have something I don't have to monkey with or worry about coming out of adjustment. And before everyone gets up on their high horse declaring how terrible DPMS is, the rifle has been very reliable and functions %100. The AR platform gets accuracy from the trigger and barrel above almost all else. If I can shoot a 2'' group with 147 gr. ball that's all I need. Just wondering if other lr-308 owners have had similar experiences with over gassing.

July 1, 2017, 09:30 AM	#10
MarkCO Senior Member Join Date: October 21, 1998 Location: Colorado, USA Posts: 4,307	Yes, all .308 ARs are over-gassed. I have a 16" mid-length gas AR pattern .308 with a heavy .308 buffer and an adjustable gas block that is very pleasant to shoot. While not a fan of adjustable gas blocks, almost a necessity on .308 pattern ARs. I prefer the Superlative Arms. While I will not try to talk anyone into any particular barrel length, longer barrels with longer gas systems do help soften recoil impulses, but do not overcome the need for adjustable gas in the .308 pattern ARs. Realize that, as opposed to .223/5.56, in .308 the commercial rounds have a higher pressure than the NATO rounds. Most ARs are set up still be reliable with the softest NATO rounds with some extra gas. That makes the commercial really overgassed. __________________ Good Shooting, MarkCO www.CarbonArms.us

June 29, 2017, 08:12 PM	#2
ed308 Senior Member Join Date: November 5, 2016 Location: DFW, TX Posts: 1,147	Almost all AR10 are overgassed. I have a Bushmaster AR10 in .308. I put a heavy buffer in mine and installed a muzzle break. Helped slow down the cycle plus reduced the recoil.

June 29, 2017, 08:15 PM	#3
nadrepadre Member Join Date: September 12, 2012 Posts: 27	Maybe a heavy buffer is the solution. Any recommendations?

June 29, 2017, 08:56 PM	#4
Mobuck Junior member Join Date: February 2, 2010 Posts: 6,846	Not to mount the "high horse" but I wouldn't even want a 16" .308. I have a 20" .308 bolt action carbine and it's about as obnoxious as I really care for. A 16" is NOT for me. A 20" heavier contour barrel would help with the recoil and adjustable gas blocks aren't all that expensive these days.

June 29, 2017, 09:01 PM	#5
ed308 Senior Member Join Date: November 5, 2016 Location: DFW, TX Posts: 1,147	I put a Spikes H2 in mine. I used this muzzle break which really tamed the recoil. They have a black melonite finish. http://www.ar15performance.com/inc/sdetail/2121/35900

June 29, 2017, 09:10 PM	#6
nadrepadre Member Join Date: September 12, 2012 Posts: 27	-Mobuck I shoot a 7600 carbine in 30-06 all day and I love it. I'm not complaining about muzzle blast. When I said "high horse" I was referring to all the people who will inevitably start talking crap about DPMS because it's not a $2000 rifle. And do you think money is an issue when I'm talking about re-barreling this gun instead of getting an adjustable gas block? Did you even bother to read the thread?

June 30, 2017, 10:32 AM	#7
Mobuck Junior member Join Date: February 2, 2010 Posts: 6,846	"And do you think money is an issue when I'm talking about re-barreling this gun instead of getting an adjustable gas block? Did you even bother to read the thread?" I didn't realize I made an issue of the cost. " the recoil and shock transmitted through the rifle is pretty extreme." I did mention that a heavier contour barrel would decrease the perceived recoil and that an adjustable gas block would address the "over-gassed" condition you mentioned in the header. Did you want advice or not?

June 30, 2017, 03:23 PM	#8
nadrepadre Member Join Date: September 12, 2012 Posts: 27	Get off your high horse It's pretty hard to convey and interpret what people say just through typing on a forum. I meant no offense.

July 13, 2017, 05:31 PM	#13
ronl Senior Member Join Date: December 2, 2007 Posts: 1,100	My 16" CMMG CBR isn't brutal at all. The brake on mine works very well.

July 16, 2017, 03:07 PM	#14
bfoosh006 Senior Member Join Date: February 17, 2009 Posts: 1,089	Heavy rifle length buffer..... https://www.kakindustry.com/lr-308-p...e-buffer-heavy Tubbs Flatwire .308 spring ... https://www.midwayusa.com/product/98...tainless-steel If those don't work out... then seriously consider an adjustable gas block.... Almost all .308 ar's are over gassed, I am going through the same thing. The cyclic speed is WAY faster then needed ( or wanted ) One thing to remember... sometimes adding all that mass to the recoil cycle can be a step backwards ( muzzle dip from a super strong spring slamming all that mass into the breach face ) ... so personally I avoid excess strength springs.

July 16, 2017, 08:05 PM	#15
marine6680 Senior Member Join Date: July 24, 2012 Location: Parker, CO Posts: 4,594	So many AR pattern 308s are over gassed. Even with a new barrel, and an 18in using rifle gas is about as low as I would go, it may not fix the problem fully. My PSA when I first got it, was way over gassed. I had to use a steel 9mm buffer and added three tungsten weights, just to get it to not unlock/extract too quickly. A new 20in barrel reduced the issue, so I can use an H2 buffer... but I still want to get an adjustable gas block for it.