Accuracy issues with 22LR Pistol Suppressor

[Machineguntony]

I took this 22 pistol to the range today. It is a Ruger. I noticed that my groups were much wider with a suppressed pistol. So I tested the accuracy issue by doing an experiment. I shot eighteen rounds from a supported position, of which 9 were suppressed, and nine were unsuppressed. I used the same ammo, which was Remington 22.

Here is a picture of two targets.

Both are at 12 yards, which I shot from support to maximize accuracy.

Notice that the left target, which is the unsuppressed, is much more accurate. The right target is the same pistol, and same ammo, suppressed.

I don't think sights were an issue, as I could see the sights above the suppressor. See second pic below.

Any comments on the suppressor accuracy? What could I be doing wrong? Is it me or the suppressor that is contributing to the inaccuracy? Does anyone else experience this issue?

 

[BillM]

First thought is that the suppressor isn't in line with the bore, and you
are clipping a baffle. Or the suppressor is very dirty and the bullet is
hitting buildup.

 

[Theohazard]

There are two possible causes that come to mind. First, I've seen situations with .22 silencers where the host firearm's threads were too long, and that put the muzzle too close to the first baffle. And if you have a suppressor with asymmetrical baffles, that can make the muzzle blast destabilize the bullet causing accuracy issues. In extreme cases this could cause baffle strikes, but when I saw it happen it only caused bullet stability issues but no baffle strikes. With the worst case, the can was a Spectre II and the host was an M&P-15 .22, and the rounds actually keyholed into the target. That rifle has threads that are too long (about 0.6") for most .22 suppressors, which is not uncommon with factory threaded .22 rifles. Pistol threads are usually the correct length; all the thread adaptors I've seen on Ruger SR-22s seemed to be standard suppressor length (about 0.4"), but is it possible the threads on the adaptor you're using are longer than that? If so, the problem is easily fixed with a $10 spacer from Gemtech or SilencerCo that's meant specifically for this issue.

Also, some .22 silencers have a baffle design that can cause stability issues with some .22 ammo. It seems this problem mostly shows up on some monocore designs, and the specific silencer I'm thinking of is the AAC Prodigy; earlier generations of that can caused bullet stability issues with some ammo, and that's why AAC offers a free upgrade to the newer baffle design. You didn't say which silencer you're using, but is it possible you're using an older AAC Prodigy or one with a similar baffle design?