March 30th my stamp came in and I took possession of my new GA Resistance 9, joy!

Today I finally had a chance to go to the range with it. I didn't futz with it; I installed the proper booster (13.5 LH for the funny euro threading on my Sig P320 factory threaded compact) and that was it, beyond the appropriate lubrication at the appropriate places.

The first two mags suppressed went just fine, and then I noticed nothing was hitting the target. WTF. Not even 40 rounds through it.

So, this happened.





That's the second time Federal Aluminum cased ammo (in this case 115gr 9mm, previous case was 230gr 45acp out of a 1911) didn't bother to stabilize in the luxurious accommodations of a rifled barrel.

Fortunately none of the baffles were damaged; there was a bunch of spray inside but it actually looks like they weren't even making it past the booster assembly before tumbling. It took a fair bit of effort to get the assembly off the barrel...

Here's the bottom of the threads:



Left side:



Doesn't look too bad, right? Well...









So, my best guess - somewhere around the 3rd mag one of two things happened -

A) Either the round didn't stabilize, touched the booster assembly somewhere and basically yanked the suppressor down, ganking the threads on top...

Or -

B) The threads on top stripped under recoil and allowed the suppressor to tilt when shooting.

I'm honestly leaning towards B but I'd be happy to be wrong.

Fortunately no can damage beyond the endcap, and as soon as I find the time and money I'll order another endcap for one of GA's compensators  No damage anywhere that can't be replaced; the baffles must have taken some kind of hit but I'll be dipped if I can find any damage anywhere even after I shook out an easy 30gr of shaved bullet jacket and bits.

So, protip: Avoid fed aluminum cased shit if you plan on putting it through a can. Once is happenstance, twice is not a coincidence. For blasting ammo without a can, it's fine, but it's not stable enough to go through a can. And now I get to call Sig and ask wtf, why did this happened to their barrel...

Ouch. Good thing it was just the cap.

I have a P320 Tacops TB, will definitely keep an eye on it.  So far about 150-200 rounds out of mine and functioning well.  Using an Octane on it.  

I did notice that it seemed more accurate with 124s and up, did not seem to like 115s as much.

Those threads are fucked. Whatever was on there got cross-threaded and was hard enough to split the threads, just like if you engaged the half-nut in the wrong place on a lathe.

those threads look as screwed up as the threads on that HK that was posted the other day.

That was my thought, but there's no way I crossthreaded this thing on. Before screwing it on I backed it until I heard and felt the thread click into place and then threaded it on, and I threaded it on slowly. There wasn't a hint of resistance until the very end when the o-ring in the piston was sliding over the very end of the barrel, and that's normal on a LH metric thread. The only things I can come up with are a thread failure all by itself, or a strike yanked the can hard enough to jack the threads. Either way...end result is the same.

Can you clean the threads some and retake the pictures again?  Lots of cap on there making it hard go see the actual threads.  Should have come with thread protector.  How was the ammo before the can install?

I agree. I think the can backed off a little and got cocked, then the bullet hit it and yanked it past a thread.

It came with a thread protector. Threads were fine before can went on. Ammo was fine, shot to POA before putting the can on.





This was after an ultrasonic bath and cleaning...that rub mark at the front of the barrel wasn't there before today's range trip.

The O-ring was/is definitely in the piston, and I felt it snug up against the exterior of the barrel when threading it on...that was one of the reasons I was wtf at this; I know it's not supposed to back off. Hell for the first mag every 5 rounds I checked it just to make sure; tightening by the piston cap. Trying to tighten it by twisting the whole can would have loosened the can off the piston I checked all of this, dry, at home before going to the range. This wasn't the first time the can was on the gun, it was just the first time it was out with live fire...

Your threads appear recut they are pretty shiny for one time session.  Can shot dry or wet?  How sharp are the threads on the piston?  How about a picture of the piston threaded to the barrel only?

Does your can allow you to change the poi like Tirant?  By pulling can away from barrel and turning either left or right until it locks to the next position.  Interesting mark (smiley) on top of the barrel and that it doesn't appear on the bottom or sides.  I wonder what the booster spring weight is.  

You also mention Fed Aluminum 230 grain 45ACP.  Did you have another issue with that?

I wonder if the o ring is getting pinched causing the can to be canted, but that would not explain the two mags that were problem free.

That blows man. After reading story after story all I buy is good brass to run through my suppressor now.  It isn't a guarantee but it seems to be a lot better than steel and aluminum in regards to strikes.

Can was shot dry

Threads are shiny, I'm guessing, because of the effort it took to get the can back off after I noticed the end cap strike and that nothing I was shooting was hitting the target. It took a lot of effort to get that can back off, even though it took none to get it on.

Yes, the Griffin Armament cans can be adjusted like Sico or AAC cans. The booster spring is the factory one, so I don't know what the weight is...but it's a pretty stiff spring.

I had an end cap graze in a 1911 shooting Fed aluminum 230gr. It was in a Storm Lake barrel that had a bunch of other issues, so I didn't think too much of it, just chalking it up to a crappy barrel (which Storm Lake wound up replacing). After this, I'm not so sure it was a barrel problem...or at least, the issues with the barrel might not have extended into shitty rifling and/or an uneven crown or something...

I would call Sig CS to see what they will do.  Along with your can's mfgr.

Came to post this.

Last photo, I wasnt sure if the threads were fucked or I was seeing some schmoo in between threads... further examination and consensus: They're fucked.

Thanks, I appreciate that. I'm pretty confident it's not a can or piston issue in any way; I've already replaced the endcap, chalked up to the cost of learning Fed Aluminum is crap. If you guys want to inspect the piston (maybe there's an irregularity in the threading? I didn't see anything but I'm in no way qualified for anything like that), I'll be glad to drop it in a box and send it. I'll mail tech@, thanks!

BOOM!!!! LIKE A BOSS!!! Stuff like this here makes me happy that I bought one of your cans.