Suppressors Huge Shift in Zero with SpecWar

[Michael12789]

Good evening Gents,

Today I got to shoot my Savage Model 10 P-SR with 18" with a 7.62 SpecWar suppressor(same as the one I purchased). My group is sub MOA normally and remained sub MOA with the suppressor, but my POI was 14" high compared to my POA.

Is there any reason in particular as to why there was such a huge difference in POI at 100 yards?

 

[RobertB]

Harmonics. I've never heard of one that big and high either. Is it consistent? Is so that's one good thing.

 

[jasonfaz]

Threads. Coaxial variation between the brake and your barrel's threads is throwing of concentricity. Your 'smith can fix that pretty lickety split.

 

[Michael12789]

Yes, it grouped nice but 14" high.

 

[Michael12789]

I don't think my smith is competent enough to do what you're saying.

 

[0311@LAR]

If it's repeatable, and accuracy is good, don't worry about it.

 

[TWANGnBANG]

If it's repeatable, and accuracy is good, don't worry about it.

I disagree. A POI shift that great is indicative that something isn't right, especially on something as stiff as an 18" heavy barrel. A good can should not affect bullet flight that much if properly aligned.

OP should contact SilencerCo if he does not trust his gunsmith to diagnose and/or literally straighten everything out. They will help you figure out the best course of action.

 

[Geno C.]

As bad as 14" shift is, if it's up and repeatable I would say you just gained yourself about 14 Moa on your scope adjustments...

 

[Michael12789]

As bad as 14" shift is, if it's up and repeatable I would say you just gained yourself about 14 Moa on your scope adjustments...

I was thinking maybe it is because my bullet is getting much more velocity from 18" plus the 9" of the specwar.

 

[mtrmn]

I sent a non-threaded AR bbl to get it threaded and when it came back the threads were not concentric with the bore. The shoulder behind the threads WAS concentric or perpindicular with the centerline of the bore. I have no idea how that could possibly happen but it did. When I tightened the QD adapter it actually bent the threaded portion of the barrel down and to the left enough to throw my zero off to 7o'clock about 30" at 100 yds. I did not screw the suppressor on it. When I took the adapter off, my zero returned to normal. Had to send the bbl off again and get it fixed.
If you tried a thread-on suppressor and screwed it on tight, you may possibly be experiencing the same thing. If you have a flash suppressor that fits, screw it on and torque it up. See where your POI goes.

 

[Geno C.]

I would have to say it would be close to or actually impossible to increase velocity enough to gain 14" at 100 yards

 

[Jig Stick]

my POI shifted when I put my Specwar 7.62 on as well…when used both on my 300winmag and 6.5x47. Shift was up and slightly left. About 1.5-2inches at 100yds. And i wasn't too pleased with that…..

 

[Geno C.]

An inch or two happens fairly often. 14" is an entirely different story

 

[Michael12789]

I disagree. A POI shift that great is indicative that something isn't right, especially on something as stiff as an 18" heavy barrel. A good can should not affect bullet flight that much if properly aligned.

OP should contact SilencerCo if he does not trust his gunsmith to diagnose and/or literally straighten everything out. They will help you figure out the best course of action.

That is exactly what I did yesterday; I contacted SilencerCo to see if we can get this straightened out.

 

[gunshinestate]

May I ask what the can is attached to, their brake mount or their flash hider mount?

 

[mtrmn]

Here was my problem. In the pic of the attached QD adapter and suppressor you can see a slight gap on the right side between the barrel shoulder and the adapter. This is with the adapter LOOSE-not torqued. When torqued, the adapter face and barrel shoulder match up. This in turn pulls the threaded section to one side and causes the huge change in POI.
In the target pic, up in the upper right quadrant you can see a small piece of paper with an X on it. That was my POA, while POI was 21.5" at about 730. When I loosened the adapter the threads sprang back to original position and POI returned to normal. All this was at 100 yds.
In my previous post I was going off of memory and reported an exaggerated 30" POI shift. My apologies for posting false info. I sent the barrel off a 2nd time to have it re-threaded, which reduced the 20" bbl to about 19"

 

[Michael12789]

May I ask what the can is attached to, their brake mount or their flash hider mount?

It was attached to their muzzle brake.

 

[Michael12789]

View attachment 48590View attachment 48589

Here was my problem. In the pic of the attached QD adapter and suppressor you can see a slight gap on the right side between the barrel shoulder and the adapter. This is with the adapter LOOSE-not torqued. When torqued, the adapter face and barrel shoulder match up. This in turn pulls the threaded section to one side and causes the huge change in POI.
In the target pic, up in the upper right quadrant you can see a small piece of paper with an X on it. That was my POA, while POI was 21.5" at about 730. When I loosened the adapter the threads sprang back to original position and POI returned to normal. All this was at 100 yds.
In my previous post I was going off of memory and reported an exaggerated 30" POI shift. My apologies for posting false info. I sent the barrel off a 2nd time to have it re-threaded, which reduced the 20" bbl to about 19"

Now I see what you're saying. Should I contact Savage to have them take a look at the threads?

 

[Skyking]

I would not go back to Savage to have it fixed. Use a good smith.

Just saw this video .
TS Customs - South Dakota's Best Kept Secret! - YouTube

 

[mtrmn]

Now I see what you're saying. Should I contact Savage to have them take a look at the threads?[/QUOTE

The way you worded the OP leads me to believe that YOUR suppressor is still waiting for the ATF to approve and you borrowed the use of someone else's to test on your gun. If this is the case, I'd wait to see what YOUR suppressor does. When you shot with the suppressor, did you install the adapter AT THE SAME TIME or had you already shot the gun with the adapter on it? If threads are the problem, it should show the huge POI shift with or without the suppressor as long as you leave the adapter on.

I had an UN-threaded bbl on a post ban AR15. I sent the bbl to have it threaded. It came back and I installed a YHM adapter on it, which showed the threads to be non-concentric before I ever put the suppressor on. I then sent the bbl to YHM, the maker of my suppressor, and had THEM thread it. I'd seen on their website that they would thread bbls. I figured they couldn't argue about warranty with a baffle strike if THEY threaded the bbl.

If you still have the adapter on your barrel, establish a POI with it in place and then remove it and do the same with a bare muzzle. (no thread protector) Does POI move a huge amount?? I would think it would not move at all or no more than an inch due to harmonics. If it moves a lot, your threads are probably like mine were. Like another poster said, get a gunsmith with a lot of experience threading bbls or maybe the suppressor mfg can fix it for you.

If it's OK with the adapter, but bad with the suppressor, then it would be something with the suppressor or alignment. COULD still be a thread problem causing a slight baffle strike, who knows til you try it?

There are many other threads in here that recommend smiths for bbl threading as well. But DON'T jump to conclusions without SOMEONE doing a little troubleshooting. It will prevent a lot of headache later.

Bear in mind I am NOT the expert a lot of these other guys are-just someone who had a specific problem and corrected it. YMMV