Suppressors - first round impact shift

[hibernation]

Got my first suppressor recently, Diligent Defense Enticer LTi, direct threaded on a Weatherby Vanguard (Howa 1500) 18" 7mm-08 for hunting. Seems to group fine for a light hunting rifle with Barnes 120 TTSX (10 shot group ~1.5 MOA off sandbags), no stringing or anything weird, but I noticed yesterday that the first cold round through the suppressor impacts 2" high at 100 yards. Every other round after groups normally to the zero POI, but if I leave the bolt open and let it cool / air out, the next round impacts 2" high again. Then returns to center.

Repeated this same pattern three times in a row: cold shot hits 2" above my aim point, next shot is right within the normal POI and expected group size.

To be clear, this isn't a POI shift from unsuppressed to suppressed, or from removing/reattaching the suppressor. It seems to just be the first round through a cold suppressor impacting 2 MOA high, then the POI immediately returns to my zero and shoots normally as long as I continue firing at a reasonable pace for a thin barreled hunting rifle. Not letting it get super hot, but not letting it fully cool either.

Anyone else run into this? Is this a thing with certain suppressors and not others? Related to first round pop? Found an older thread on snipershide of a similar situation.

Range Report - COLD BORE WITH SUPPRESSOR

So i am having trouble with my cold bore shot having a different POI then the rest of my shots. Desert tech a2 with a 16” 6.5x47 lapua barrel and a varminter 3.0 30 cal can. It does the same thing with my 18” 300win mag barrel also. First shot is always about 1” low and 1” right with both...

www.snipershide.com

 

[Lawnboi]

Probably more related to your barrel than the suppressor. I’m not sure how DD designs their cans but if this was an issue you would likely see more.

I have no shift on my rifles for first round, though they are often around 15- 20fps slower. Whether that’s the can being filled with air, or the extra friction of the carbon in the bore oxidizing I don’t know.

 

[hibernation]

Could be, I need to check that. I haven't really shot this rifle much without the suppressor. If it was a barrel issue, would you expect the POI to keep moving as the barrel continues to heat? I've read the cold bore vs hot thread, not sure where the vanguard/howa barrels fall in terms of proper stress relief.

I'll check that on the next range trip, shoot it unsuppressed for a few to see if the POI shifts as it warms up, then maybe throw the cold suppressor onto a hot barrel and see where that lands.

Also need to put it on another rifle and see what happens. Got a hunt coming up real soon and I thought this rifle was all set, gotta get this sorted out.

 

[Whistlepigs]

I have this same issue with a Badrock South Fork. First round suppressed is always about 1.5" right. Same can on other rifles are fine, just this one.

 

[jhoff04]

I just listened to a recent meateater podcast on suppressors and this exact problem was brought up during a discussion. Sounded like it was a known problem with older designs but apparently with how most suppressors are designed today, you shouldn't see this issue?

 

[hibernation]

I have this same issue with a Badrock South Fork. First round suppressed is always about 1.5" right. Same can on other rifles are fine, just this one.

So just that one combo of suppressor and rifle? What suppressor was it?

 

[TaperPin]

Got my first suppressor recently, Diligent Defense Enticer LTi, direct threaded on a Weatherby Vanguard (Howa 1500) 18" 7mm-08 for hunting. Seems to group fine for a light hunting rifle with Barnes 120 TTSX (10 shot group ~1.5 MOA off sandbags), no stringing or anything weird, but I noticed yesterday that the first cold round through the suppressor impacts 2" high at 100 yards. Every other round after groups normally to the zero POI, but if I leave the bolt open and let it cool / air out, the next round impacts 2" high again. Then returns to center.

Repeated this same pattern three times in a row: cold shot hits 2" above my aim point, next shot is right within the normal POI and expected group size.

To be clear, this isn't a POI shift from unsuppressed to suppressed, or from removing/reattaching the suppressor. It seems to just be the first round through a cold suppressor impacting 2 MOA high, then the POI immediately returns to my zero and shoots normally as long as I continue firing at a reasonable pace for a thin barreled hunting rifle. Not letting it get super hot, but not letting it fully cool either.

Anyone else run into this? Is this a thing with certain suppressors and not others? Related to first round pop? Found an older thread on snipershide of a similar situation.

Range Report - COLD BORE WITH SUPPRESSOR

So i am having trouble with my cold bore shot having a different POI then the rest of my shots. Desert tech a2 with a 16” 6.5x47 lapua barrel and a varminter 3.0 30 cal can. It does the same thing with my 18” 300win mag barrel also. First shot is always about 1” low and 1” right with both...

www.snipershide.com

Wow - 2 MOA is a lot. The first thing that came to mind is a very slight baffle strike and the can is lucky enough to expand with heat away from the bullet.

It’s a bummer to have to sort it out, but I’ll be excited to hear what the fix is since it’s such a dramatic problem.