Suppressor POI Shift

[SublimeOutdoors]

Looking for advice on shooting with a suppressor. I have a Remington 700 Sendero in 7mm Rem Mag that I've enjoyed shooting for years and have recently gotten a Proof Research Switch rifle that I've moved to for weight reduction among other variables. My 7mm will shoot quite well with a Thunderbeast Ultra 9 and I have minimal point of impact shift when shooting with suppressor on then off. However my new Switch rifle in 6.5 PRC has substantial POI shift when shooting suppressed versus non. Can anyone enlighten me on why? Thunderbeast are known for the minimal POI shift. I'm confused on this.

 

[Ah1356]

You are hanging a weight on the end of the barrel, and that will change the harmonics unpredictably. It might create a big POI shift, or a small one, or none, but in general heavier suppressors and flexible barrels have the potential for greater POI shift. I have an 18-in .308 and a 26-in 6.5x47 and I use the same suppressor on both rifles. The .308 has very little POI shift, but with the 6.5x47 the shift if 0.2MILs down and about 0.05MILs right compared to a bare muzzle. I have seen guys with more than twice that POI shift. So long as the POI shift is consistent (and thankfully mine is) it's easy to account for the difference.

 

[SublimeOutdoors]

I figured with the Carbon fiber barrel it should be less affected than the stainless fluted barrel, but I was greater than 2 moa off when suppressed on the Proof 24" barrel.

 

[Excavator]

I wonder if it has something to do with a change in MV? Is the shift vertical or horizontal?

 

[SublimeOutdoors]

I wonder if it has something to do with a change in MV? Is the shift vertical or horizontal?

The shift is 1 MOA right and 2.5 MOA down at 100yards. I'm still going through barrel break in and the groups are great with the suppressor on and off, but the POI shift is insane.

 

[Ah1356]

The POI shift is not really related to MV, at least not in the obvious way. The can is not causing the bullet to go slower and hit lower. In general the suppressor can add a little speed, so if velocity were the primary cause here it would hit higher. I haven't studied it formally, but I think generally the difference is harmonics, and the direction of the shift can be up or down, left or right, depending on your barrel/suppressor/load. My suppressor is fairly heavy, and on a 26 inch barrel my 0.2 MIL POI shift down is pretty small. I don't think your 2.5 MOA shift is surprisingly large, especially for a carbon barrel, which I suspect is not terribly stiff. So long as the shift is consistent, just account for it and you're good to go.

 

[Excavator]

Good info, I have zero experience with cans. However I am trying to decide the best route to go for my new creed with a 20" proof. Gun was built to run a can. Did any of y'all see the info on the new Gunwerks cans? Trying to decide what to buy.

 

[Ah1356]

I don't know much about the Gunworks can, and I am no expert, but here's my free advice: My suppressor is an Allen Engineering AE30, and it is excellent. It is also heavy and requires a non-standard muzzle profile. Most people want light and standards threads. If you have a Proof carbon barrel, you probably can't use the AE30. If I had to get something different I'd go with a Thunderbeast Ultra in the length that makes sense for your application and the largest caliber you shoot. My can is a .30, and it works great on my .308, my shiny new 7 Sherman Short, and my 6.5x47. You can shoot a small bullet through a large can. Not so much vice versa... Last thing - buy now, and try your best to forget about it while the good folks at the ATF and the FBI waste your time and money for months of needless delay...

 

[cohunt]

The other thing to consider with a poi shift and a can is that the can both increases weight and reduces recoil--- both of these can affect the shooter. Less recoil will usually show a lower poi due to less muzzle rise/flip/jump.
This could be the cause of the 2.5 moa lower poi you are seeing

 

[hunter67wa]

stiffness of the barrel and barrel length also if and how the barrel is bedded. Carbon fiber barrels are not stiffer than steel. There is a very good thread here explaining that

 

[rjtaylor]

I can't tell you why yours is different between guns but mine shifts much more than yours on all of my guns. I wish the shift wasn't as much but I guess it doesn't matter too much since I always run my guns suppressed.

 

[DSMITH1651]

Hell my poi shift is 6.25 moa but a least its consistent LOL. 26 in prof research

 

[mcali2]

The only rifle i have ever had POI shift besides up was on a carbon fiber barrels. I went through 3 barrels to get it right. Im not sure if there are pockets of air in the carbon or what? I have no idea. But it works now.

 

[mcali2]

Also check the baffles inside. make sure none of them have any strikes or rubbed. It is possible. I have seen 1 rifle have light strikes multiple times. we did not know about it until the can was shot off the rifle. turns out the threading was off on the can.