Home Forums Hunting & Shooting AR and Tactical Rifles AR 15 questions

I believe there’s two versions of the AR15, one had a gas tube that carries gas back to cycle the bolt. The other the gas pushes on a rod that in turn pushes on the bolt to cycle it.
Is that correct?
What is the terminology for them?
All else being equal, which is most accurate?

Thanks

Piston driven
Direct impingement
All else being equal I'm going to guess equally accurate

Got two piston driven and two more to install. Haven't seen any decrease in accuracy

Gas impingement would be most accurate.

Probably can't see any difference in a non-match grade barrel however.

Are piston AR's losing favor?

It doesn't seem like I see them much, especially new releases. Well. it's Ruger & they aren't all that big into AR's, but they've dropped their piston model.

I have a AR-15 Question???

I have a 30 yr old Bush Master that's fired thousands of rounds, and bounced around in my Jeep for 30 years, it got to were i couldn't hit a beer can at 50 yards.

so rebuilt it new 1 x 7 Barrel 16" new hand guard, new butt stock buffer and spring , Timmeny Trigger, Bolt and all internals replaced new, Leupy 3x7 Fire Dot scope.

Took it my range yesterday fired 3 rounds at 100 yards about 4" fired 3 Rounds at 200 Yards about 20' spread, shooting 52 gr, SP.

My question is ? are the 52 gr. to light for a 1x7 twist, As in spin out of control? would a 62 gr. or 77gr. but a better fit for this barrel? factory ammo only, I don't reload .223 I can buy it cheaper than reloading. Function is perfect. Rio7

It could depend on the bullet but we used to shoot a lot of 50 grain hollow points through many 1/7 guns with respectable accuracy.

But I have a decent shooting gun that hates Hornady 75 grain HPBT ammo while my Kimber which is a 1/9 twist just loves it.

No, I shoot Speer 52 Match out of a 1/7 AR and it does just fine.

52s shoot awesome in 1/7 twist barrels.
I'd guess you have a bad scope or barrel.

I only fired 10 rounds total, not a very good sample this is a top quality barrel ,and the scope has been a dependable scope, I am not going to change anything, until I have time to shoot it some more and use some different ammo and bullet weights. Your thoughts and comments are appreciated . Thank You Rio7

Maybe the rifle just doesn't like that particular ammo.... Try some other is what I'd do first..

Might have less to do with bullet weight, and more to do with jacket thickness/hardness. You'd expect Hornady SX and Sierra Blitz to be unsuitable. Was never able to get Remington PLHPs to shoot well out of 1:7s or 1:12s. Suspect the gas port is at least partially responsible.

As to accuracy deterioration one of my 1:7 11.5" Colt bbls has had around 20k, nearly all full auto and nearly all sequential mag dumps. You might think that's extreme, but the LV range folks run their barrels out to around 100k. Of course, they aren't exactly accuracy testing.....IIRC their backstop is about 50 feet.

Anyway, decided to range test that 11.5 with my best M855....did about 12" for 5 at 100 yds. Not horrible. Borescope revealed the expected washed out throat and grand canyon gas port. Was surprised to see deposits of carbon literally in clumps throughout the barrel.

So I got serious. Did alternating courses of Kroil/paste and EABco Patch out. After a few weeks (yes, I typed that) it looked alot better. And it put 5 into 4.5" at 100 yds, with irons no less.

If your BM has been shot as much try aggressive cleaning. Try other 52/53 gr heads - Sierras seem reasonably tough. And try heavier weights.

What scope, what mount?

^ THIS ^

I bought a Remington 30-06 ADL for $200.00 a few years ago. Guy said he couldn't hit anything with it. I tried it out and I couldn't either. Changed scopes and it became my #1 rifle.

Jim

Now come on no Leupold bashing here. But don’t leave us in suspense. Was it a bushnell banner or Leupold?

Scope is a Leupold 2 X 7 Fire Dot, Burris one piece mount I have both for over 10 years no problems.

Went to the range just at dawn this morning, with 52gr. 55 gr. 62 gr. 69 gr. Hornady S.P. that's all i had in .556, shot 10 rounds of each in about 2 hours while shooting other guns in between mag and ammo changes. the 62 gr. shot about 3/4" at 100 yards, the 69 gr. shot almost 1 hole at 100 yards, this rifle does not like the 52gr.and 55gr.

This Trigger needs to be lightened up, it must be about 5--6 # think that would help improve this rifle a bunch. Thanks for you comments. Rio7

Mine was about 7 lbs. with a little work and springs it’s now 4.5 which is livable till I get time. Did have to get anti walk pins after changing the springs.

I never changed the trigger on this rebuild, before it was about 3# with all of the new parts it is suprisingly stiff?? Rio7

I've experienced similar patterns with 1/7 barrels and light bullets although it varies depending on the barrel and the bullet. Sometimes light bullets will shoot well.

Sounds like it's time to get a new trigger. I personally like Geissele SSA-E triggers. They're spendy but go on sale pretty regularly.