ar15 expert advice [Archive] - Glock Talk

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billy b
05-27-2011, 17:31
i have a dpms varmit upper. 24'' heavy barrel, 1 in 9 twist. when it was new it would shoot under an inch at 200 yards. lately more like 2 inch + groups. bore does not seem to be copper fouled. upper has been shot maybe 700 or so. i need advice as to what the problem might be. i've tried cleaning barrel with everthing i have and it hasn't helped. what can i do to the upper to get it shooting good again.

STI
05-27-2011, 17:40
Barrel crown damaged?
Sights loose? Ammo change? Ever get the barrel real hot? Clean it with Sweets 7.62, patches come out clear?
For that much of a difference I doubt its copper fouled that bad, but could be.

JBnTX
05-27-2011, 17:53
Somethings loose somewhere.
Sights? Scope? Barrel?

Are you using handloads?
If so, what have have you changed?

Rifles love handloads. That way the load can be tailored to the individual
rifle for the best accuracy.

Don't over clean it!
You'll do more damage than good.

Maybe it's just a bad barrel?

Sweets 7.62 is POWERFUL stuff. Use it sparingly and don't leave
it in the barrel for an extended period of time.

Only the worst of fowled barrels with thousands of rounds should be exposed to
Sweets 7.62 solvent. With only 700 rounds fired I'd refrain from using Sweets 7.62.

Believe it or not, you can destroy a barrel very quickly by over cleaning.

Randy from Kansas
05-27-2011, 18:37
Every thing that has been stated above, plus bags, bench, wind and mirage.

Under an inch at 200 yards is a very good group was it 3 shot or 5 shot. Could you repeat it several times in a row or did you get one 7/8 group and 2 more at an inch plus.

Really need more information,

I was shooting my 24inch Colt A3 this afternoon at 100yds and had a couple under 1/2 with hand loads. I am trying to find the right combination of powder bullet and OAL for best groups. Here is a picture I took

billy b
05-28-2011, 10:58
barrel is stainless. shooting same reloads as when it was new.50 grain nosler bt, h335. mounts are tight, warne rings. friday i put 3 shots in same hole at 200 yarda. next 2 groups 2 inch + again. i shot my bushmaster same day and shot it great. so i know my ability to shoot is still good. scope is a sightron 6x24.

faawrenchbndr
05-28-2011, 11:03
The "three shots in the same hole" grouping, was this the first grouping?
Clean bore?

Randy from Kansas
05-28-2011, 11:36
On the last two groups over 2 inch did it place them vertical or horizontal. Horizontal would tell me wind, and vertical could be mirage.

What type scope do you have on your Bushmaster? Can they be placed on your DPMS?

AK_Stick
05-28-2011, 11:40
Sweets 7.62 is POWERFUL stuff. Use it sparingly and don't leave
it in the barrel for an extended period of time.

Only the worst of fowled barrels with thousands of rounds should be exposed to
Sweets 7.62 solvent. With only 700 rounds fired I'd refrain from using Sweets 7.62.

Believe it or not, you can destroy a barrel very quickly by over cleaning.



Solvent, will not hurt the steel of the barrel.

Now, you can do some serious damage with a improper use of a brush or jag or whatever, but the solvent is not going to affect the steel in the slightest.

billy b
05-28-2011, 18:29
3 in one hole was the first or second group out of a clean barrel. next four or five groups were just scatered, no horozontal or veritical stringing. i allowed barrel to cool between groups. bushmaster has a nikon 6x18 on it. truth is i have bushmaster shooting great. it shoots 1 1/4 groups at 200 yards. i hate to have to mess with it. i do have a bushnell 4x12, but i don't think it's enough scope.

BBJones
05-28-2011, 21:37
10 shot groups would be more meaningful. 3 shot groups introduce all kinds of statistical anomalies. Even 5 shot groups would tell you more.

thisaway
05-28-2011, 22:51
Solvent, will not hurt the steel of the barrel.

Now, you can do some serious damage with a improper use of a brush or jag or whatever, but the solvent is not going to affect the steel in the slightest.

Sweet's 7.62 contains a high percentage of ammonia, which will damage the barrel steel if left in the bore for a long period of time.

AK_Stick
05-28-2011, 23:36
Q. What does Lilja Rifle Barrels think of the use of bore solvents with ammonia?

A. While we're aware of "bad press" associated with the use of cleaners with ammonia as part of the solution, we have never seen any damage in one of our barrels caused by the use of ammonia. The rumor is that copper-removing cleaners with ammonia will pit and damage the interior surface of a barrel. Ammonia is very effective as a copper remover. We use solvents, such as Butch's Bore Shine, to remove copper during the break-in. We routinely leave Butch's solution in the barrel over night too. Again, I repeat, we have never seen a problem with ammonia in the concentrations found in commercial cleaners, in either our chrome-moly or stainless steel barrels. This includes examination with our borescope.

I really, really doubt it.

Ammonia is used to clean guns after corrosive ammo has been fired, and black powder guns. While it can be bad for the stock, and can cause surface rust, which will require more cleaning later, I'm really not buying it's going to hurt the bore.