Question regarding accuracy when shooting suppressed

[TXHOGKILR]

I am new to this forum & suppressors so hopefully you guys have some good input for me. I have a AAC 762 that I am using for my 300 BLK & my 308. In my 308 I'm shooting 150 grain Hornady supersonic ammo just to reduce the blast a little. When I shoot the 308 without the suppressor I hit bullseye at 100 yards. When I put the can on the gun & shoot the exact same ammo I get a 1/2" group but it is 12 inches low from the "non suppressed" shots.

Is this normal? I know the can will slow down the bullet a little but it shouldn't be 12" low at 100 yards should it? Thanks in advance for your help.

[rimshaker]

POI shift is part of silencer life unfortunately, especially rifles. Doesn't always happen. Some cans are better than others. Tons of different variables that contribute to shifts.

The most important thing is that the POI is repeatable and consistent. No random flyers all over the place. Just adjust your scope accordingly and make a note of the new settings.

[Bird]

Yes it is normal. The suppressor changes the barrel harmonics. Best solution...always shoot with the can on.

[Historian]

Yes it is normal. The suppressor changes the barrel harmonics. Best solution...always shoot with the can on.

Excellent observation!

A neglected but important parameter.

The Designers of the .303 Lee-Enfield Rifle accounted for it
with a floating feature that few are told about. The Sniper Rifle
was one of the most accurate rifles I ever shot out to 600 yards.
Scoped. But oh my poor shoulder.

Best.

[Will_M]

You hang a weight on the end of a long barrel and it's going to bend (or deflect in engineering terms) downward.

That's what's causing your POI shift.

[66427vette]

12 inches is a ton. Specs of rifle? Something is off.

[GHEN]

That is a 12MOA shift. Sounds like a lot.

GHEN

[RJT]

You might try a different brand of ammo, and see if there is less POI shift. Its possible your gun doesn't like that load with a can on it.

[Theohazard]

I know the can will slow down the bullet a little

This is a very common misconception, but it's not true. A can will either have no noticeable effect on velocity or it will actually increase velocity a very small amount.

[66427vette]

Sounds like a s--t thread job . Is it a savage ?

[Alangaq]

I don’t think a 12" POI shift is unusual at all. The OP didn’t give specifics on his rifle however if you have a relatively light contoured barrel longer than 22" with a fairly heavy can hanging off the end; then I would be surprised if you were still on paper after taking the can off..

With my model 7 in 300 blk when the barrel was 16 1/2" my POI shift with subsonic loads using Hornady 225 gr HP's was about 8" at 100 yds. Once I cut the bbl back to 10 1/2" the POI shift dropped to about 6". As posted earlier by others, barrel harmonics are in my opinion the largest factor in POI shift and it would be reasonable to assume that the longer the barrel or the heavier the silencer is, then the more POI shift you can expect.