question about POI shift with suppressor

[VolGrad]

I have owned several rimfire pistols in the past. The first was a Ruger 22/45 with adjustable sights which was threaded by a local shop. This was an amazing little pistol and I wish I had it back. I have asked the guy I sold it to if he'd sell it back several times but he loves it as much as I did. The second was a Browing Buckmark with a TacSol threaded upper. I never felt the love for it. It was sold and replaced with this factory threaded 22/45 .....

http://www.ruger.com/products/2245Th...ets/10150.html

Unfortunately, I don't love this one as much as I did the first 22/45 I owned. This one has fixed sights which don't seemt to be zero'd. I have to fire a couple of rounds each time I take it out to recall exactly where the POI is relative to the POA then adjust. Not a big deal on a plinker but not ideal. I'm actually considering selling or trading it for one like I had before. I can pick one up locally easy enough as the local shop still sells them already threaded.

That's not really my question. Here's my question;

When I screw on my AAC Aviator the POI immediately shifts about 3 inches dead left of where this gun is hitting without the can. I have tested with multiple ammo types/brands and the results are all the same.

This never happened with the two previous pistols I owned and doesn't happen on my Ruger 10/22 with the can screwed on.

It was suggested to me perhaps the factory threading on this pistol is "off" and this might explain the shift. I haven't really inspected the threading to see if it looks to be out of spec but the both the can and thread protector screws on without any effort or sticky spots.

Does that explanation make sense?
Anyone ever experienced this?
Any other ideas what might cause this?

[SamuelBLong]

I have owned several rimfire pistols in the past. The first was a Ruger 22/45 with adjustable sights which was threaded by a local shop. This was an amazing little pistol and I wish I had it back. I have asked the guy I sold it to if he'd sell it back several times but he loves it as much as I did. The second was a Browing Buckmark with a TacSol threaded upper. I never felt the love for it. It was sold and replaced with this factory threaded 22/45 .....

http://www.ruger.com/products/2245Th...ets/10150.html

Unfortunately, I don't love this one as much as I did the first 22/45 I owned. This one has fixed sights which don't seemt to be zero'd. I have to fire a couple of rounds each time I take it out to recall exactly where the POI is relative to the POA then adjust. Not a big deal on a plinker but not ideal. I'm actually considering selling or trading it for one like I had before. I can pick one up locally easy enough as the local shop still sells them already threaded.

That's not really my question. Here's my question;

When I screw on my AAC Aviator the POI immediately shifts about 3 inches dead left of where this gun is hitting without the can. I have tested with multiple ammo types/brands and the results are all the same.

This never happened with the two previous pistols I owned and doesn't happen on my Ruger 10/22 with the can screwed on.

It was suggested to me perhaps the factory threading on this pistol is "off" and this might explain the shift. I haven't really inspected the threading to see if it looks to be out of spec but the both the can and thread protector screws on without any effort or sticky spots.

Does that explanation make sense?
Anyone ever experienced this?
Any other ideas what might cause this?

Factory threaded is not always better.

I've seen some factory barrels out by .015 - .030, and our desired tolerance is +/- .003

If your threading and or more importantly the thread shoulder ( how the can actually indexes) is off center/perpendicular to the bore its possible that the bullet could be impacting / skimming the baffle stack.

Carefully inspect your baffles and end cap and see if there is any wear / deformation on one side.

[VolGrad]

Carefully inspect your baffles and end cap and see if there is any wear / deformation on one side.

I plan to check the threads, thread shoulder, and can this evening as best I can to see what I can see.

[VolGrad]

To wake this thread up with an update .....

I inspected threads on both the host and the can and couldn't find anything that looked off.

I recently purchased a Advantage Arms factory threaded barrel for my GLOCK conversion kit. I shot it for the first time yesterday and had the same issue. With the factory non-threaded barrel and the factory threaded barrel (sans can) the POI was POA.

As soon as I screwed on the can the POI shifted about 3-4 inches dead right at approx 10-11 yards. This would make me think it was the can and not the host or host barrel, right? I really don't think that's the case though given the can is POA/POI for me on my Ruger 10/22 at 50yrds.

I really need another rimfire only day next weekend just to play with this some more.

Thoughts on what's causing the shift? Is it a distance thing? I'm at a loss.

[TAP]

Call Mark K. and ask him. I think it is pretty common but I don't know the exact reasoning.

[VolGrad]

Call Mark K. and ask him. I think it is pretty common but I don't know the exact reasoning.

I might do that but I never saw it on the previous host pistols I owned.

[TAP]

I know it is very common on long range stuff.

[VolGrad]

I just picked up a new host today so I hope to test it out again this weekend. The new host is a 22/45 with TacSol TB upper.

I'll shoot them all with and without can and at different distances and record my results.

I also e-mailed Bookhound to see what he thinks.