I had read an article saying that the first shot out of a silencer is likely to have a different point of impact than the following shots. The different point of impact for the first shot is because the silencer is full of air rather than from the gaseous products of combustion of the previous shot. The gas in the silencer after the first shot is much heavier than regular air. I don't know how true that is but I bought a sleeping bag mattress air pump and use it to blow out the barrel and silencer between shots. That is, my silencers are on hunting guns and I am concerned with the point of impact of the first shot not any successive shots. I also let the silencer cool off between shots.

I don't have extensive experience with a suppressor but I do shoot with one. I have a 700 Light Tactical in 308 that is a very good shooter. I was concerned with doing anything to it that might effect the accuracy but I had it threaded for my suppressor. The results have been surprisingly good it may actually shoot better with the can on it and I can see no difference with the first shot point of impact. I may have just got lucky.
DH

I've heard of air in the can causing "first round pop", but never heard of air in the can affecting POI.

The POI on my rifles does not change.

Take one of your threaded rifles to the range.

Fire a shot with the can off, then two more shots within a minute.

Did your POI differ between the first shot from a cold barrel and the two subsequent shots?

Once the barrel has completely cooled, repeat the test with the can attached.

Hoe do those results compared with the unsuppressed barrel?

George

I don't get a POI change either. At least no different than the slight dispersion you see as a sporter contour barrel heats up anyway.

I was curious about this myself.

Today I went to the range and did some informal testing. I shot three 5-shot groups with the same rifle (700 Rem with a stiff Hart 6x45 barrel) and the same supersonic loads. Two with the suppressor (groups one and three), one without at 100 yards. This rifle routinely shoots sub MOA.

I made a point of shooting the first shot through a cold bore and a cold suppressor. I was load testing other rifles so I waited 10+ minutes before groups and had a Chamber Chiller inserted to cool things off.

POI shift for the first shot through the cold suppressor was about 1/2 inch. The next four shots were clumped together Same thing happened with the second group shot with the suppressor ~90% cooled off.

POI shift (difference?) for the group fired without the suppressor was about 1.5 inch different.

This was for this particular rifle and a rather short/informal test at 100 yards. One needs to ask if 1/2" or 1.5" at 100 yards is a factor.

Someday I will repeat the drill at 200 yards and see what it translates out to

quote:

Originally posted by Matt Norman:

POI shift for the first shot through the cold suppressor was about 1/2 inch. The next four shots were clumped together Same thing happened with the second group shot with the suppressor ~90% cooled off.

POI shift (difference?) for the group fired without the suppressor was about 1.5 inch different.

Your testing showed that POI shift was lessened when firing through the suppressor.

Bullets should never touch the interior of a can (cold or hot), so barrel harmonics were apparently 'enhanced' when the can was was deployed.

I always sight my scopes in for the first shot from a cold barrel, suppressed or not.

George