POI Shift

[Black Tail Hunter]

while confirming my zero this weekend I also had my first opportunity to try out my new suppressor. I zero at 300 yards and when I shot through my can I wasn't even on paper. I was expecting a POI shift but was a little surprised at how much I was getting. I didn't have time to try and sort it out with deer season opening this weekend so I just figured I would tackle it after season.

Does this amount of shift seem excessive or in line with what is "normal"?

I was shooting through a YHM Phantom 330ti QD,

 

[wyowinchester]

One of my cans had a 3" shift at 100yds. Yes it could do that. But, it did group great.
Try it at a shorter distance and adjust from there.

 

[Black Tail Hunter]

That's what I had planned on just starting from a closer distance. I don't mind having to correct my zero point to adjust for shift due to the suppressor I just don't have any prior experience to know if that much point of impact change was something to be concerned about. Thanks for your response

 

[wyowinchester]

It will differ from one rifle to another. Just record the PIO of each, or leave them zeroed for the can on.

 

[THEIS]

Hello,

A POI that goes from "On paper" to "Off paper" from mounting suppressor is WAY excessive. Did your POI go back to "On paper" once you removed the suppressor?
Have you checked to see if you had any kind of baffle strike?
Was your suppressor "locked" on its' mount properly?
Is your suppressor mount installed properly?

Thanks,
THEIS

 

[Black Tail Hunter]

A POI that goes from "On paper" to "Off paper" from mounting suppressor is WAY excessive.

Even given the zero distance of 300 yds?
Yes went back on paper after removal.
I looked at the exit hole and there was no sign of damage.
Yes suppressor was locked to mount, it is a ratchet so you spin it till it stops.
Suppressor mount is installed correctly as far as I know. its timed so the ports are at 3:00 & 9:00. I used a Geissele alignment rod to check prior to shooting (which quite frankly I wasn't overly impressed with). However the rod was very close to perfectly centered with only a slight amount of misalignment which could have been as easily from the fit of the rod in the bore as much as the suppressor being off the bore centerline.

 

[Cuz]

Really depends on the weight of the suppressor and contour of the barrel. My 338 tbac is pretty heavy and will change poi quite a bit on thinner barrels. My ultra 9 is a lot lighter but will still change a remington varmint barrel about an inch at 100.

 

[Black Tail Hunter]

I figured that is probably playing into it as well. My barrel profile is quite light and is a heavy recoil round. The Suppressor is fairly long and even though it is titanium is still a lot of weight hanging out there, probably has a drastic effect on the barrel whip.

 

[Black Tail Hunter]

Have you checked to see if you had any kind of baffle strike?

Looked down it last night with a reach light, no baffle strikes.

 

[woodnut]

I have several mufflers and all are direct attach. Yes, I have POI shift, but it varies with each rifle, calibre from very little to maybe 4 inches. All have been left for some odd reason. Accuracy is ALWAYS better with the can! Since you confirmed no baffle strikes and it is attached properly, all I can say is go shorter til it "zeros" and move on out to hunting distances. It should work out even with the light barrel as the can improves harmonics on all weight barrels.

 

[jasonprox700]

I too have noticed that accuracy ALWAYS increases with a suppressor! I'm not sure if it's that lack of recoil that reduces any flinch that may be present or the fact that it acts on the barrel harmonics.

I only run a few suppressors, so take this for what it's worth, but I also find the POI shift in my factory suppressors. It varies between rifles, but it is consistent on each rifle.

I have noticed that on my Form 1 cans (homemade) I do not see the same POI shift as my factory can (GA Alpha). There are a few differences between my F1 cans and factory. The first is the size of the holes in the baffles. I pretty much run oversized (.400-.410") when the factory cans only run about .050-.060" over bore. I also use different "clips" than any of the factory cans out there. Also, the suppression of my F1 cans is on par or better than factory to my ears and a few others. Metered, it may be different.

 

[woodnut]

I too have noticed that accuracy ALWAYS increases with a suppressor! I'm not sure if it's that lack of recoil that reduces any flinch that may be present or the fact that it acts on the barrel harmonics.

I totally agree ; but it's both reasons!

 

[Snyper708]

jasonprox700 said: ↑
I too have noticed that accuracy ALWAYS increases with a suppressor! I'm not sure if it's that lack of recoil that reduces any flinch that may be present or the fact that it acts on the barrel harmonics.

Another factor is the reduced muzzle blast doesn't upset the bullet as much just as it's leaving the barrel.

 

[woodnut]

Another factor is the reduced muzzle blast doesn't upset the bullet as much just as it's leaving the barrel.

Well, that's a thought I hadn't thought of! I do believe it, too.