SIGforum
Expected POI Shift Suppressed vs. Unsuppressed

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https://sigforum.com/eve/forums/a/tpc/f/380105858/m/2100014164

September 26, 2019, 04:29 PM
PorterN
Expected POI Shift Suppressed vs. Unsuppressed
I expected a POI shift. Thats why i did the test - two five shot groups with the suppressor, two without, twice. It just got me thinking: is there a typical differential shift yall see in your POI when shooting suppressed vs unsuppressed? my shift is straight vertical - ive read some that go in any direction. But contributing factors -Is it the brand, the barrel, the guns? The suppressors weight? Just curious if this is about typical with yalls experiences too.

My range day:
With this new DD5v1 I just got, I took it to the range this morning before work to finally test it out. Unfortunately I only had time for the short indoor range. I got the gun bore-sighted but it was about 6” high and 4” left at 25 yards. I got it dialed down and set to be roughly 2” high at 25 yards, but this was more function than precision today. I was getting damn good groups at 25 yards - better than i typically have shot before with other guns, so that was encouraging. However, when i put my SilencerCo Omega 300 suppressor on the rifle, it dropped my shots to POA/POI. 2” lower at 25 yards with a suppressor. The bigger problem was that the groups opened way up to where the holes weren’t touching anymore, with my worst group being 3” or so. That was kind of sad.

So I tried it with my AR15 and KAC suppressor, and it actually did about the same differential: ~2” lower when suppressed, but this time it helped the accuracy and made a better group.

Anyway, it was a successful trip - I absolutely love the rifle. Its all just me getting to know the quirks of the gun, too.



____________________________
While you may be able to get away with bottom shelf whiskey, stay the hell away from bottom shelf tequila. - FishOn
September 26, 2019, 06:21 PM
George from Alaska
It's kind of all over the bi as rd for me. A DA Ghost suppressor on a pistol has almost no poi shift at 25 yards, my monocore cans almost always are 2-4 inches off.
Rifle cans vary for me from no shift with a big Gemtech .338 can at 330 yards to my Rugged Surge which is almost always 4" high at the same 330 yards. I literally write on the mounting collars or can body with a white paint pen what the shift is, if any, for any can and don't worry about it anymore. It even seems that a can with no shift on one rifle or po pistol will have shift on another gun. My Linerty Cosmic shoots low on my HK Mark23 but is almost dead on when I put it on my HK45T .45? Barrel harmonics?? I don't know, I just make note of it. If I dedicate a specific can to a specific gun like I do with my DA Ghost on the Mark 23 then I put red paint marks on the can, the booster, the piston threaded part and on to the gun barrel so I can always clock or time the can to the gun.


P220 European
P220 Scorpion
P220 10mm Legion
MK25
P226 Legion
P226 SAO Legion
P229 Legion
556 rifle, my favorite 556
P320 M17 (not the expensive
one) with Leupold DPP
P227 Tac-ops
machineguns
suppressors
07/02
September 26, 2019, 07:25 PM
arlen
Is your sight system a red dot or elevated supressor sights for that pistol?


Regards,
arlen

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Some days, it's just not worth the effort of chewing through the leather straps.
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October 28, 2019, 10:04 AM
gw3971
I have a 20" AR15 and a Silencerco Specwar 556 can. It shoots 3 moa low and 1 moa left on this rifle. The same can has no shift on any other rifle.
November 04, 2019, 11:36 PM
gw3971
went out and shot my new 762 can on an AR10 and a 300 Blackout AR with no shift what so ever today.
November 05, 2019, 10:24 AM
RHINOWSO
Yeah, I don't see a real rhyme or reason with POI shift.

I'm sure its a combination of rifle & barrel contour / suppressor mount type / suppressor design / etc.

Also threading concentric (or not) and shoulder can have huge play in it. I had a 10/22 barrel threaded by a guy, along with sight set back. I would put the suppressor on (SiCo Sparrow that showed zero POI on multiple other rimfires) and I shit you not, it would shift up and right to 2 o'clock and 6 inches - at 25 yards. No baffle strikes, just some wonky shit going on.

Putting a shim behind the suppressor for a better shoulder cured some of the magnitude, but it still shifts up 2 inches. Other rifles don't care, with essentially zero shift.