Thread: Suppressor changing point of impact by inches

Shot my ar15 today. With the suppressor on to sight it in. I then shot it without as the suppressor was hot. The point of impact went up 6 inches or so high.

Any suggestions on what would cause this. I was shooting Barnaul but I don't think it'd have anything to do with it.

Cheers.

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You should probably mention this was 6" at 25m..

What did you expect to happen?

Adding or removing anything from the muzzle is always going to affect point of impact.

Sometimes a little, sometimes a lot.

In this case, quite a lot.

Barrels move a fair bit with a bullet moving down it . Anything that add/subtracts weight to the barrel will effect how it moves .

Originally Posted by Tommy

You should probably mention this was 6" at 25m..

If it was that much its pretty excessive

Heavy suppressor on a light barrel ?

Originally Posted by Kiwi Greg

If it was that much its pretty excessive

Heavy suppressor on a light barrel ?

Nah it's a DPT on a heavier 223 barrel, short for the profile too. Baffle strike probably isn't an issue either, it's a .30 can from memory. Took it apart and checked for strike.

You will get a POI change without a suppressor, but 6 inches is a lot at 25m. Only thing I can think of is to try that again with different ammo in case barnaul was an inconsistent batch.

2-3" at 100 could be considered normal, 6" at 25 is indicative of misalignment of the suppressor. This could be as a result of poor threading, shoulder damage, bent suppressor, poorly made suppressor, etc. It needs to be checked with an accurate alignment rod before you shoot it again. A very light barrel would not help the situation due to muzzle whip.

Originally Posted by systolic

What did you expect to happen?

Adding or removing anything from the muzzle is always going to affect point of impact.

Sometimes a little, sometimes a lot.

In this case, quite a lot.

I knew it would change but wasn't sure if that much was normal.

Originally Posted by Clint Ruin

Barrels move a fair bit with a bullet moving down it . Anything that add/subtracts weight to the barrel will effect how it moves .

True.

Originally Posted by Max Headroom

You will get a POI change without a suppressor, but 6 inches is a lot at 25m. Only thing I can think of is to try that again with different ammo in case barnaul was an inconsistent batch.

I have some brass cases fmj at home I'll try.

Originally Posted by gundoc

2-3" at 100 could be considered normal, 6" at 25 is indicative of misalignment of the suppressor. This could be as a result of poor threading, shoulder damage, bent suppressor, poorly made suppressor, etc. It needs to be checked with an accurate alignment rod before you shoot it again. A very light barrel would not help the situation due to muzzle whip.

Ok. The shoulder looks fine, the dpt has lasted about 80 rounds of 308 fine so I am thinking that it's ok.

I got it threaded by a machinist friend. He also did my 308. I was going to get a stainless steel blast baffle from Darren so may see if he'll have a look at it. ..

Cheers for the advice.

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Originally Posted by Russian 22.

I got it threaded by a machinist friend. He also did my 308. I was going to get a stainless steel blast baffle from Darren so may see if he'll have a look at it. ..

Cheers for the advice.

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Did your friend centre the work on the bore when he did the threading? Make sure it wasn't centred on the outside of the barrel.

On two .308 rifles, one mine and the other my mate's, the addition of the suppressor changes the POI to about 3" high at 100m. Every other suppressor I've seen lowers the POI. Barrel harmonics I guess.

Originally Posted by Russian 22.

I got it threaded by a machinist friend.

Did he indicate off the outside diameter, or the bore? Like @gadgetman, I'm leaning towards this cause

If the suppressor is slightly off to the bore that should not really make a difference with the point of impact, if the bullet is touching the baffles that will defiantly cause accuracy issues.
My guess is that the rear bush is touching the barrel on one side potentially bending the barrel inside the suppressor, try removing the rear bush and shooting it, before shooting it make sure the suppressor is a nice fit on the barrel thread and is not wobbling around.

Originally Posted by gadgetman

Did your friend centre the work on the bore when he did the threading? Make sure it wasn't centred on the outside of the barrel.

I will check and get back to you.

Originally Posted by 10-Ring

On two .308 rifles, one mine and the other my mate's, the addition of the suppressor changes the POI to about 3" high at 100m. Every other suppressor I've seen lowers the POI. Barrel harmonics I guess.

Originally Posted by chalkeye

Did he indicate off the outside diameter, or the bore? Like @gadgetman, I'm leaning towards this cause

I will check.

Originally Posted by DPT

If the suppressor is slightly off to the bore that should not really make a difference with the point of impact, if the bullet is touching the baffles that will defiantly cause accuracy issues.
My guess is that the rear bush is touching the barrel on one side potentially bending the barrel inside the suppressor, try removing the rear bush and shooting it, before shooting it make sure the suppressor is a nice fit on the barrel thread and is not wobbling around.

The rear bush is touching the barrel pretty uniformly on both barrels I use it on. There's barely any gap between the barrel and bushing.

Ok. Will do. Thanks a lot.

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Originally Posted by Russian 22.

I will check and get back to you.







I will check.



The rear bush is touching the barrel pretty uniformly on both barrels I use it on. There's barely any gap between the barrel and bushing.

Ok. Will do. Thanks a lot.

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We give the bushes clearance, about 0.05mm over size, open it up a little so its not touching the barrel.