Group shift with suppressor

[The Annoyed Man]

My son's Savage with his home-built suppressor, last Tuesday at ETTS.

https://www.youtube.com/watch?v=VxvsecSOQJY

And my SCAR 17 (which is normally STUPID loud) with the same suppressor on it:

https://www.youtube.com/watch?v=CAgH6G1Du9Y

[WildBill]

I guess my earlier post didn't make it to the database.
I was looking at the website for Liberty Suppressors and they said that a 4-6 inch shift in POI was "fairly common".

Shift of 4 to 6 inches at 100 yards is fairly common in most suppressor designs and should not alarm you, as long as it is repeatable. Your data book will be your friend at this point…..or simply zero your rifle system with the suppressor mounted and don’t shoot it without the suppressor.

It sounds like you're doing pretty good Andy.

https://libertycans.net/education/faqs/poi-shift/

Andy - I had a question about your scope mount. Why did you choose this particular one?

[Bitter Clinger]

I guess my earlier post didn't make it to the database.
I was looking at the website for Liberty Suppressors and they said that a 4-6 inch shift in POI was "fairly common".

Shift of 4 to 6 inches at 100 yards is fairly common in most suppressor designs and should not alarm you, as long as it is repeatable. Your data book will be your friend at this point…..or simply zero your rifle system with the suppressor mounted and don’t shoot it without the suppressor.

It sounds like you're doing pretty good Andy.

https://libertycans.net/education/faqs/poi-shift/

Andy - I had a question about your scope mount. Why did you choose this particular one?

I have not seen a group shift with the can on my SBR, but it is a .308 can that I have taken to running on my 5.56

I was on the range with another guy who did mention that he sees a very consistent group shift on his 5.56 carbine when the can is mounted.

[The Annoyed Man]

Hmmm, good to know - home-built cans rock

Why the mount? Well, I needed a 20 MOA rail and I like/trust the precision of EGW's 1911 parts, so...

And my SCAR 17 (which is normally STUPID loud) with the same suppressor on it:

I meant to ask - did you notice any gassing back into the magazine (like you originally saw on my FAL before I drilled weep-holes), or did the extra weep-holes in his first 2 baffles work fine?

None at all. The original weep holes he drilled that day seemed to take care of it. Perhaps it's a matter of the SCAR's gas system being slightly different than the FAL's? Who knows? It was a moderately windy day that day as you can tell from the sound quality of the 2nd video, so maybe the wind simply carried off the gasses before it could bother me.

One other thing which I just now realized..... The SCAR has a two position gas regulator, with one position for suppressed, and the other for unsuppressed fire. I never set it to the suppressed position. I simply forgot all about it, but the rifle seemed to run fine, feeding and ejecting brass smoothly.

[mrvmax]

I have some change in POI with my a Liberty Mystic but not as pronounced as you.

[The Annoyed Man]

I have some change in POI with my a Liberty Mystic but not as pronounced as you.

Firing my 5.56 AR15 suppressed and unsuppressed, with a .308 caliber AAC can mounted on it, at 50 yards I noticed no discernible shift of POI. The shift came with subsonics, where the POI dropped 2"-3" from POA at the same distance (nor did those loads have enough poop to cycle the bolt, so that kind of drop is not surprising).

But this is a .30 caliber can with 5.56 bullets, so maybe there is enough gap between the bullet shank and the baffles that any minor variances don't affect the bullet. Also, it is entirely reasonable to assume that factory made cans use baffles that are more precisely formed, perhaps on CNC equipment, whereas the baffles in these home made cans are drilled out on a drill press in a garage. So no matter how careful, there is bound to be a lack of concentricity measurable in the 1/1000ths range.