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About to give up on my large frame AR

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One more interesting tidbit... When I was loading for the original barrel I was noticing round ejector marks on the brass pretty early, 2-3 grains below published maxes. Today, I noticed nothing of the sort, even with some flatt(er) primers on the black hills factory stuff. The flat ones had longer to bake in the chamber while I was setting up aim.
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The BH factory ammo has some pressure signs. Primer flow around the firing pin(not always a pressure sign). Flat primer.
 
Meangreen said:
The fact that it shoots fairly well when the gas is off shows that it is not the load.

Try one more thing. Someone mentioned this in the earlier thread, load rounds from the magazine one at a time. So put a round in the magazine, lock the bolt back, insert magazine, and let the bolt go home from pressing the bolt release. Fire the round letting the bolt lock back and repeat.

What this will do is make sure every round is loaded from the magazine and the bolt will lock up with no bolt drag from rounds pushing up from the magazine. If the groups tighten up, then you know bolt drag from the magazine is preventing consistent bolt lock up.

I use 10 round magazines in my precision AR's for this reason. I usually put just 5 rounds at a time in them. When single loaded in the manner described above, this gun shoots under 3/4 MOA consistently. When I use a 20 or 30 round magazine the very same loads will open up to 1 3/4 MOA.
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I'll give it a try. I've been loading 5 rounds at a time.
 
I tried Varget, IMR4064, RL15 with 165, 168, 175, 178s had no good luck in my 18" 308 11 Twist AR10. I then tried XBR8208 and 125 Sierra TMK on a quick 300 Yard ladder test and found a narrow sweet spot. So i tried it again and it was about .5 grain window. Figured id just shoot light weight bullets till i tried the 178 ELDX with XBR8208 and found it would shoot amazing. So now i just load the 308 with XBR and 125s for blasting and 178s for hunting.
 
243winxb said:
Looking at your loads and velocity, compared to below, looks like your loading to hot, high pressure.?. Try some H4895 and load down, just to work the action. (Youth load powder data rule)

Maybe time to trade? This one shoot well. https://www.americanrifleman.org/articles/2018/1/10/tested-pof-usa-revolution-rifle/

View attachment 1032209 POF-USA Revolution Rifle
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I haven't had any real pressure signs - that POF rifle has a 16 inch barrel and I'm shooting a 20 so it seems about right
 
nonnieselman said:
I tried Varget, IMR4064, RL15 with 165, 168, 175, 178s had no good luck in my 18" 308 11 Twist AR10. I then tried XBR8208 and 125 Sierra TMK on a quick 300 Yard ladder test and found a narrow sweet spot. So i tried it again and it was about .5 grain window. Figured id just shoot light weight bullets till i tried the 178 ELDX with XBR8208 and found it would shoot amazing. So now i just load the 308 with XBR and 125s for blasting and 178s for hunting.
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Nice. I've got a gallon of 8208 and will give it a shot (no pun intended)
 
AR10s are over gassed my two course uppers (.308 and .260) have the ports moved 1.6" and 1.8" farther forward from rifle position, also run the CWS in them. Slow the gas down and they shoot fine at least for NRA HP.

The 260 Upper was originally an Eagle Arms 10T upper. It shot ok, but it showed pressure signs real quick with 175gr SMKs.
 
HI, I had a fiend who's high dollar ar shoot poorly. It was sent back times to the company for a fix. The company said everything was fine and sent some 3 shot groups back to him. What we eventually figured out was the scope was moving under recoil back and forth. He added a second set or rings so the scope could not move in the rail. The rifle now shoot to the 1/2 inch groups. May not help, but worth a few minutes of your time to try it.
 
oldhoward said:
HI, I had a fiend who's high dollar ar shoot poorly. It was sent back times to the company for a fix. The company said everything was fine and sent some 3 shot groups back to him. What we eventually figured out was the scope was moving under recoil back and forth. He added a second set or rings so the scope could not move in the rail. The rifle now shoot to the 1/2 inch groups. May not help, but worth a few minutes of your time to try it.
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That's crossed my mind. It's an SWFA 10x in an Aero mount... I have everything torqued properly, nothing loose or moving, and used purple loctite on the fasteners.

I do have a Vortex Razor HDII that I am tempted to put on there but I dont want to take if off it's parent gun... Guess it's worth a try.
 
The elimination of the problem when the gas is turned off points in that direction. One thing to check is that the carrier key is not dragging or binding on the gas tube. A simple check is to disassemble the BCG and slide the carrier only into the upper. The carrier should go all the forward with little or no hesitation when it mates with the gas tube. If you’re getting significant resistance then your gas tube is not aligned or you have something wrong with the carrier key. That would be my first test, then use the other scope you have. Both of those cost you nothing but time and the ammo. If the gun fails to shoot in the 1MOA area with 4895 and 168’s then I highly doubt it’s an ammo issue. M1As always worked well with 41.5 of IMR 4895 and a 168 in LC brass.

Other things to check:

Burr at the gas port - can be found with visual inspection and a tight patch on a jag.

Poor Barrel-to-upper fit at the extension. Not barre but tension, but lots of space between extension and receiver wall. This can be fixed by bedding the extension to the upper.

Loose flash hider or bad/damaged crown

Float tube touching the barrel or gas block.

I would check all of those before I bought new Brass, primers, etc. these will have a much larger impact than the other variables.
 
First, don't believe that gas guns can't shoot. I used to live near Compass Lake Engineering and I saw lots of his rifles that shot bug hole groups. We are not talking 3 shot bug holes, but 20 round match bug holes.

My first thought is to shoot it single shot with the gas turned off. Does it shoot well then? (It did well in that configuration when you were breaking it in.) If it shoots well, then something in the action movement/fit/lock up/function is causing the erratic shots with the gas turned on. Disassemble, check the fit and function of each part during re-assembly. Sounds like you have an adjustable gas system. Play with adjustment. Due to manufacturing processes used today, there are very few bad barrels. Not all shoot bug holes, but most will shoot south of 1 moa.

The SWFA is usually a solid scope. Even though everything was torqued with loctite I would still check that to verify that variable. Got a friend with a loose scope you could try?
 
dsculley said:
First, don't believe that gas guns can't shoot. I used to live near Compass Lake Engineering and I saw lots of his rifles that shot bug hole groups. We are not talking 3 shot bug holes, but 20 round match bug holes.

My first thought is to shoot it single shot with the gas turned off. Does it shoot well then? (It did well in that configuration when you were breaking it in.) If it shoots well, then something in the action movement/fit/lock up/function is causing the erratic shots with the gas turned on. Disassemble, check the fit and function of each part during re-assembly. Sounds like you have an adjustable gas system. Play with adjustment. Due to manufacturing processes used today, there are very few bad barrels. Not all shoot bug holes, but most will shoot south of 1 moa.

The SWFA is usually a solid scope. Even though everything was torqued with loctite I would still check that to verify that variable. Got a friend with a loose scope you could try?
Click to expand...

Oh I believe they can shoot. I have some incredible AR15's with WOA barrels. I went into this build with a lot of faith.
 
dsculley said:
First, don't believe that gas guns can't shoot. I used to live near Compass Lake Engineering and I saw lots of his rifles that shot bug hole groups. We are not talking 3 shot bug holes, but 20 round match bug holes.

My first thought is to shoot it single shot with the gas turned off. Does it shoot well then? (It did well in that configuration when you were breaking it in.) If it shoots well, then something in the action movement/fit/lock up/function is causing the erratic shots with the gas turned on. Disassemble, check the fit and function of each part during re-assembly. Sounds like you have an adjustable gas system. Play with adjustment. Due to manufacturing processes used today, there are very few bad barrels. Not all shoot bug holes, but most will shoot south of 1 moa.

The SWFA is usually a solid scope. Even though everything was torqued with loctite I would still check that to verify that variable. Got a friend with a loose scope you could try?
Click to expand...

I'll do those checks and see what I come up with and just suck it up and move my razor over for a while.
 
168 Amax, IMR 3031 (38.5-38.8 grs.) and CCI 200 primers reeled my groups in . I was trying a lot of loads with BR primers with no luck.
Make sure your brass has good neck tension ( .003") and annealed every time.
 
Try a different bullet man...
Initially tried the.same in my ar10. Same results. Ended up with really good consistency with.165 sierra Spitzer.
 
Gas block off/on??? Adjustable should be set where it just cycles the action. Don't want to sound like a smart ass, but just checking.
 
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