Keyholing and what manufacturers are telling me

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wahoowad
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Keyholing and what manufacturers are telling me

Post by wahoowad »

I'm trying to avoid mentioning any specific vendors. I may add more detail once I get confirmed resolution to my issue. Mainly posting to hopefully learn more.

Brought new (and first) suppressor home this weekend - a rimfire suppressor from one of the big names. Excited to say the least and mounted it on a Ruger SR22 which required an aftermarket threaded barrel to be purchased/installed. Quickly determined significant keyholing at 15' about 30% of the rounds fired regardless of the brand ammo (tried several different high and standard velocity ammos). Removed suppressor and reinstalled hand snug, nothing loose, same deal.

Moved suppressor to a bolt gun, tried same ammo, zero keyholing.

Suppressor was taken apart, inspected and reassembled as per vendor documentation. Everything appears just fine. No sign of clipping or even minor contact/damage to baffles.

Contacted aftermarket threaded barrel vendor as well as suppressor vendor and told following:

Threaded barrel vendor: "there are no manufacturing defects in our products" and "I am so adamant that it’s not our barrel or adapter is because I already know the results of our inspection." My question to the community is if it is possible for there to be no manufacturing defects when making a threaded barrel? I would think there is always the possibility, if not 100% guaranteed that sooner or later a process or material or tool or human induces some error.

Suppressor vendor: it is possible there could be clipping without any visible sign. Send it back for inspection. <-- I would think there would some sign given the keyholing at 15'. Does this sound likely there is some clipping but no sign of it?


Additionally the threaded barrel vendor said the stacked baffle design is inherently flawed and can't help but produce yaw, which is why they designed their own suppressor to not use stacked baffles. I'm new to suppressors and curious if there is any truth to this. It occurs to me their website didn't point this out on their threaded barrel sales page.
SuthDet
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Re: Keyholing and what manufacturers are telling me

Post by SuthDet »

I'd definitely say that the threads are the issue. The fact that it works fine on another rifle almost guarantees it. If possible, send the rifle and the suppressor to the suppressor manufacturer. It's much easier to see the problem with the whole system than it is with just one piece.

I'd expect the shoulder to not be square with the bore. It happens to the best manufacturers from time to time.
Fulmen
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Re: Keyholing and what manufacturers are telling me

Post by Fulmen »

While the barrel is the most obvious culprit it's impossible to say for sure without examining both barrel and silencer. 30% keyholing without any visible marks in the can suggests a "glancing blow" inside the can, which means that the error is marginalt. Even minor and totally acceptable deviations on the barrel threads can mean the difference between contact or not.
mbogo
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Re: Keyholing and what manufacturers are telling me

Post by mbogo »

Is there any keyholing when shooting the SR22 with the threaded barrel and without the suppressor? If so, clean the barrel bore down to the bare metal.

if not, I suspect the barrel threads are not concentric to the bore and the bullets are being deflected.

Do you have a one-piece .22 cleaning rod?

Remove the threaded barrel from the SR22. Screw the suppressor onto it and slowly insert the cleaning rod into the barrel from the chamber end.

See if you get any contact where the barrel muzzle meets the suppressor.

mbogo
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John A.
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Re: Keyholing and what manufacturers are telling me

Post by John A. »

Good advice here.

It can be caused from a lot of things.

Shoot the gun without the can and check for keyholing.

OK, if the gun shoots fine without keyholing without the silencer, the barrel itself is not the problem, but then you'd need to start checking the threading and shoulder of the barrel and for concentricity to the bore.

If all that checks out OK, the issue would have to lie in the silencer.

Some designs that have a very tight bore can lead to destabilization.

And that can happen without actual physical contact with a baffle. Though some light contact is more usual for that to be happening.
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Brooks@Thompson Machine
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Re: Keyholing and what manufacturers are telling me

Post by Brooks@Thompson Machine »

All good advice above!!

As the above have said, shoot the SR22 without the suppressor on to see if there is keyholing and whether it groups normally. I had a funny case here at the shop with one of our test Ruger MKIV 22/45 LITE pistols. The day it came in, I took it out and shot it suppressed for the first time and it was keyholing and shooting a random shotgun pattern all over the place with a well-tested (known to be concentric) Zephyr-L, so the silencer was definitely not the issue. We assumed the barrel threads were to blame, and were about to send it back when i decided to test fire it without a suppressor on (something I am loath to do because guns are freaking loud :wink: ). The gun shot the same random pattern without the can on, so I brought it back in and looked closely at the rifling...

Long story short, some of the epoxy (clear like rocksett) that Ruger uses to thread lock the barrel nuts on their 22/45 lite pistols had gotten into the bore and hardened, so the rifling was entirely filled for 2" or so of the barrel. A quick scrub with a phosphor bronze brush, and it is a very accurate little pistol suppressed or un-suppressed.

In your case, if your SR22 shoots well without your silencer on, it is an issue with the suppressor indexing properly. This could either be due to barrel threads that arent concentric to the bore, a barrel shoulder that is not perpendicular to the bore, or a situation in which your silencer is not shouldering because there is no relief cut at the base of the threads on the barrel or the start of the threads on your silencer. Screw your silencer onto the trouble barrel, and LOOK CAREFULLY by holding it up to a light to see if there is a gap between the back of the silencer and the barrel shoulder. If there is a gap on one side, or any gap at all all the way around, the silencer is not seating properly on the barrel shoulder and this will cause baffle/endcap strikes.

Long-winded, but there you go ;)
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