POI shift with suppressor

[mammynun]

My first and only suppressor is an AAC SDN-6 that I mount to eight long guns (10.5" to 20") that are either 5.56x45, 300BLK, or .308/7.62x51 via 51t mounts (7 Blackouts and one Brakeout). My POI shifts down and to the right for all weapons when the suppressor is attached. This shift is consistent and repeatable for each weapon, but varies between weapons. It doesn't correlate to barrel length, type, caliber, or anything else that I can figure.

Examples of shift trends (shooter error/ammo) @ 100yds:
12" CHF: down, negligible; right, negligible.
14.5" SS: down, 1.5"; right, 3"
14.5" SS: down 3"; right, 4"
20" Lilja .308: down 1"; right 3"

I get around this by taping the the change in dope to the rifles, and that works to some extent, but my confidence in cold bore shots is less than optimal. I suspect that this is the nature of the beast, and I should be happy that the shifts are repeatable over multiple suppressor attach/detach cycles. But coming from the T-10/M16A1/1911 issued generation I figured I'd ask if there's a way to eliminate or minimize the POI shift. I suspect that there's not, but maybe I can learn a new trick from you younger guys?

 

[Bourneshooter]

From what I remember, the shorter stiffer barrels have less POI/POA shift due to the weight being at the end of a shorter barrel vs longer where it affects things more.

From the tests I've seen/done, all cans have a POI/POA shift, some have less, some have more, but shorter barrels with lighter cans had less.

My Surefire had 1" down/over left on my 10.5", buddies AAC had 1" down,/3" left on his 10.5. When he put his AAC on a 16", it went the opposite direction.

@Stephen I think had more info about use on his 10.5" SCAR and POI/POA shift somewhere.

 

[Stephen]

Stiff barrel with high quality suppressor and ammo; that's the trick. The SCAR16S with its pencil thin barrel was one of the worst I've seen with 7MOA POI shift. After I cut it down to 10" that shift went into the 1.5MOA range.

 

[jwramp]

Another data point - big thick MTU-profile 6.5 Creedmoor Rem700 w/ the AAC 762 sdn-6. After zeroing with the can, the impact with the can removed is 1-in low and 1-in right at around 100-yd. Very repeatable, no noticeable change in accuracy.