POI and why it changes or not

[dammitman]

so what causes the point of impact to change when using a suppressor? and why does it shift on a lot of high dollar production models but not some others? and just the same, it can change on some peoples form one models but not change on others form one models? i understand that harmonics of barrel combined with specific load data is directly involved but as far as design of suppressor other than the weight nothing? can we agree that internal design really hasn't a lot to do with the POI shift overall. what do you think?
and i really am only concerned with the longer range rifle suppressors
after some more reading it seems that it truly is a very small percentage of people who are able to add a pound or more of weight to the end of their rifle barrel and it not change POI any. very few.

[fishman]

The bullet has to push air out of the way when its traveling through a suppressor, if the bullet is passing through an asymmetrical baffle, it is easier to push air away in some directions than in others. This creates high and low pressure zones around the bullet that push it off course. The muzzle blast can also have a effect on the bullet if the first couple baffles are asymmetrical.

[smustian]

The bullet has to push air out of the way when its traveling through a suppressor, if the bullet is passing through an asymmetrical baffle, it is easier to push air away in some directions than in others. This creates high and low pressure zones around the bullet that push it off course. The muzzle blast can also have a effect on the bullet if the first couple baffles are asymmetrical.

In addition to what fishman said, gas exiting the endcap behind the bullet can induce a yaw to the bullet tail if the endcap is not formed properly to give the gas area to expand.

[John A.]

I have seen people do a lot of things, to a lot of different baffles. I still don't pretend to know exactly what, if anything in specific makes a change.

I can say that kissing a baffle, however slightly, will create LARGE point of impact shift. And even creating more of a shotgun pattern, than a group.

So, to that, I believe too tight of a bore is the major culprit.

I have fired a lot of rounds through suppressors, going back for far more than a decade now, and can honestly say that I have never had major POI shift from a bore that is relatively large to the bullet diameter.

While it may not make for the most quiet "caliber specific" bore by itself, it works better for me considering that I shoot a lot of different calibers through my cans, so is really a moot point.

9mm silencers really sound pretty good with 22lr, my 45acp can sounds fantastic with 9mm through it. And they are accurate as can be.

On my integral, I did an experiment where I ported one side of the omega'ish baffles and left the other side solid. And I orientated each of the baffles to port to the 12 o'clock position.

Even though I expected that it would move my POI, due to the pressure being directed in a specific way, it did not.

[doubloon]

The bullet has to push air out of the way when its traveling through a suppressor, if the bullet is passing through an asymmetrical baffle, it is easier to push air away in some directions than in others. This creates high and low pressure zones around the bullet that push it off course. The muzzle blast can also have a effect on the bullet if the first couple baffles are asymmetrical.

The LID on the Gemtech MultiMount is indexed and when the suppressor is rotated to a different indxeed position the POI changes.