Sniper & Sharpshooter Forums banner

1 - 19 of 19 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter #1
I've a DPMS LR 308 with 24in bull barrel, that I had machined to accept a SureFire Muzzle Brake so that I could attach a Surefire SOCOM G2 suppressor. My problem is shooting suppressed the rifle shoots 3.5MOA. Shooting unsuppressed the rifle shoots sub 1/2MOA shooting Federal Sierra MatchKing BTHP 168 gr bullets. What can I do, what can I check, to tighten the suppressed groups up? Thanks
 

·
Registered
Joined
·
885 Posts
The thread job. The possible baffle strike.
 

·
Registered
Joined
·
4 Posts
Discussion Starter #3
Thanks gpark09. After some of my own research I've ordered a bore alignment rod to check alignment. You would of thought a prestigious gun club like the Scottsdale Gun Club in Scottsdale AZ would had recommended to me the option of having one of their gunsmiths install the muzzle brake and suppressor to check alignment for me or at least recommend I bring it back after my own installation to have a smith check alignment before use. But that was not the case. Any case I'm sure after I get the alignment rod I will be able to determine the issue. I'm not sure at this point how to correct it. My hunch is I hope the brake. I'm hoping, that it's not the machined threading that is off.

In my research I looked and have yet to find a direct threaded adapter to the suppressor that I can attach to the barrel that the suppressor will attach to without having to use a muzzle brake. This particular rifle was a bull barrel to begin with.
 

·
Registered
Joined
·
1,442 Posts
The thread job. The possible baffle strike.
I was thinking that but didn't want so say it.
If you have a bore scope I would try taking a look at the inside of the can. I suspect a baffle strike should leave visible evidence inside the can. At least a little copper residue from where the baffle shaved the projectile.
 

·
Registered
Joined
·
8 Posts
It could be a number of things. Doesn’t even need to strike the baffle to throw off a projectile. Is it still grouping and just off 3.5moa or are you actually getting a 3.5moa circle of holes while aiming at the same point? These are 2 different issues.
 

·
Registered
Joined
·
4 Posts
Discussion Starter #6
Thanks gpark09. After some of my own research I've ordered a bore alignment rod to check alignment. You would of thought a prestigious gun club like the Scottsdale Gun Club in Scottsdale AZ would had recommended to me the option of having one of their gunsmiths install the muzzle brake and suppressor to check alignment for me or at least recommend I bring it back after my own installation to have a smith check alignment before use. But that was not the case. Any case I'm sure after I get the alignment rod I will be able to determine the issue. I'm not sure at this point how to correct it. My hunch is I hope the brake. I'm hoping, that it's not the machined threading that is off.

In my research I looked and have yet to find a direct threaded adapter to the suppressor that I can attach to the barrel that the suppressor will attach to without having to use a muzzle brake. This particular rifle was a bull barrel to begin with.
I received an alignment rod today ($49.00) and checked the alignment. Sure enough the alignment was off. I backed the brake off and played with some shims. After some trial and error the brake is aligned which translates to the suppressor. Hopefully, this problem is resolved. Will know better when I can get to the range again.
 

·
Registered
Joined
·
2 Posts
One way to be sure is to take off the barrel from the upper and bring it to your machinist with the muzzle device. Have him dial out up true in the lathe. Attach your can and see how much run-out there is with it on. I've had some bad luck lately with Surefire muzzle devices.
 

·
Registered
Joined
·
4 Posts
Discussion Starter #8
It could be a number of things. Doesn’t even need to strike the baffle to throw off a projectile. Is it still grouping and just off 3.5moa or are you actually getting a 3.5moa circle of holes while aiming at the same point? These are 2 different issues.
To answer your question, the first shot out was 3 inches low and about one inch right of my previous zero. Subsequent shots where in the same area about 3.5moa spread.
I received an alignment rod today ($49.00) and checked the alignment. Sure enough the alignment was off. I backed the brake off and played with some shims. After some trial and error the brake is aligned which translates to the suppressor. Hopefully, this problem is resolved. Will know better when I can get to the range again.
Made it to the range today. My issue is resolved. Trueing up the muzzle brake made all the difference. The can makes no difference now with the rifle's accuracy.
 

·
Registered
Joined
·
1,442 Posts
Interesting that you had to shim the brake to the barrel. I'm wondering if the thread on the barrel was cut off center or the brake threads were cut off center. I'm used to seeing those crush washers used for timing the brake position relative to the rifle which is an aesthetics thing. I hadn't heard of shiming to avoid baffle strikes before. I guess that's one way to fix a bad thread job. I have 6 rifles that have a TB brakes on them that take my TB can and I have never had a problem. I bought the brakes and provided them to the smiths when I had the weapons made. I move the can from weapon to weapon. Never had a single problem with any of them as far as strikes... Had some issues with pressure with the A/R's, but that's another discussion.

I know 6 is not a large sample size but still, to have a problem with one of one. Curious whether the problem is Surefire or your smith.
 

·
Registered
Joined
·
5,228 Posts
Shims are fine for suppressor brakes and are intended to be used with pre threaded barrels.

If your smith had the brake, then shims should not have been needed and you need to find a different smith.

Crush washers should never be used in conjunction with suppressors as they do not provide a true shoulder.
 

·
Registered
Joined
·
800 Posts
Shims are fine for suppressor brakes and are intended to be used with pre threaded barrels.

If your smith had the brake, then shims should not have been needed and you need to find a different smith.

Crush washers should never be used in conjunction with suppressors as they do not provide a true shoulder.
Thunderbeast as well as some other big names supply crush washers with their products.. yeah generally if your using can only, your probably not having to time the device but on moduler systems it's the norm to use crush washers to avoid the costly gunsmithing. Like the thenderbeast break uses them but then the can threads onto the break so I would say it's going to depend on your rig
 

·
Registered
Joined
·
5,228 Posts
Thunderbeast as well as some other big names supply crush washers with their products.. yeah generally if your using can only, your probably not having to time the device but on moduler systems it's the norm to use crush washers to avoid the costly gunsmithing. Like the thenderbeast break uses them but then the can threads onto the break so I would say it's going to depend on your rig
Thunderbeast does not use crush washers. I have been a dealer for thunderbeast for a few years now. Thunderbeast supplies peel washers with their brakes for timing.

The difference is, peel washers hold true to the shoulder of the threads. If the barrel is threaded true, then the peel washers will keep it true. Crush washers can crush at different rates causing the suppressor to go out of true leading to a baffle strike.

For this reason, crush washers should never be used with suppressors or suppressor brakes. If you used them and it worked, you got lucky.
 

·
Registered
Joined
·
800 Posts
Thunderbeast does not use crush washers. I have been a dealer for thunderbeast for a few years now. Thunderbeast supplies peel washers with their brakes for timing.

The difference is, peel washers hold true to the shoulder of the threads. If the barrel is threaded true, then the peel washers will keep it true. Crush washers can crush at different rates causing the suppressor to go out of true leading to a baffle strike.

For this reason, crush washers should never be used with suppressors or suppressor brakes. If you used them and it worked, you got lucky.
Your right,, I do remember that now that you mention it. Lol, I remember burning my finger tips separating them
 

·
Registered
Joined
·
800 Posts
Your right,, I do remember that now that you mention it. Lol, I remember burning my finger tips separating them
I would think one could simply strike marks 180° from eachother and measure from each one to a given point on the barrel and tell if it's off center.. if you did that in 4 places (every 90°) all readings should be identical and if not you'd know you had a centering ptoblem?
 

·
Registered
Joined
·
800 Posts
Your right,, I do remember that now that you mention it. Lol, I remember burning my finger tips separating them
I would think one could simply strike marks 180° from eachother and measure from each one to a given point on the barrel and tell if it's off center.. if you did that in 4 places (every 90°) all readings should be identical and if not you'd know you had a centering ptoblem?
 

·
Registered
Joined
·
800 Posts
I would think one could simply strike marks 180° from eachother and measure from each one to a given point on the barrel and tell if it's off center.. if you did that in 4 places (every 90°) all readings should be identical and if not you'd know you had a centering ptoblem?
Have you tried area419? I've switched over to all area419 and no longer have to deal with shims, crush, peels etc, all their devices are self timing.. its a pretty neat system
 

·
Registered
Joined
·
5,228 Posts
Area 419 brakes are very nice and simple to time. I love their design.
 

·
Registered
Joined
·
800 Posts
I would think one could simply strike marks 180° from eachother and measure from each one to a given point on the barrel and tell if it's off center.. if you did that in 4 places (every 90°) all readings should be identical and if not you'd know you had a centering ptoblem?
Have you tried area419? I've switched over to all area419 and no longer have to deal with shims, crush, peels etc, all their devices are self tim
 
1 - 19 of 19 Posts
Top