I went out Saturday and did some shooting. I shot an upper with a suppressor mount I’ve shot before. I took the suppressor off and put it on a new mount on a new upper I haven’t shot before and attempted to turn it back one notch but it wouldn’t budge. I thought maybe since the can was hot and the mount was cold (about 40° that day) that did something to it to make it stick. I thought maybe if I heated the mount up it would free the can so I did a quick mag dump and then attempted to remove the can - no luck. Got back home, took the upper off and put it in my vice via a Geissele Reaction Rod and attempted to twist the can off but still no luck.

Parts: YHM Phantom can, YHM QD mount

Any thought in what’s happened? Any ideas on how to get this can off?

Yeah putting a hot suppressor on a cold mount is generally a bad idea and can cause it to get stuck. First thing I'd try is getting it very hot (mag dump is easiest way) and then try to remove it. If that's not an option try soaking it in some penetrating oil.

It got stuck one other time when I left the can on the gun for an extended period after shooting.  I had to take the mount off the barrel (with the can still attached) and I soaked the the mount end of it in a cup of something, possibly WD-40, I don’t remember exactly.  After soaking for a time, I don’t remember how long, I was able to twist the can off with no problem, just like it’s supposed to.

It’s currently soaking in WD-40, again.

I'm not familiar with that can. I had the same happen with a dead air but the brake came off. I had to take the suppressor apart to fix it.

Kroil penetrating oil will work. Had to soak a 9mm 3-lug SMG can once. Stuck it was! This item should really be in everyone's tool kit.

Attached File

I think I have some Kroil, I’ll give it a try.

I can't find the picture, but I just cut the top of a Coke can, rinsed it out, and filled with Kroil until the mount (3-lug piston in my case) was covered. Of it doesn't come apart in the allotted time, just give it more time.

Addition: It'll also help break up all the crud around the threads. Helping prevent this in the future.

YHM suppressors often get stuck on the QD mount.  Not a big deal and no knock on YHM, just happens a lot.  The carbon fouling gets in the spring and keeps it from compressing thus not allowing you to unscrew it.  I think most people have good luck soaking it in some kind of solvent to break the carbon loose.  I've always thought an ultrasonic cleaner would work.  Worst case scenario, you can take the snap ring off the back and disassemble the mount.  Clean it and then reassemble.

I was able to get a screwdriver between the spring and the can and pry back a little but it didn’t help.  I don’t think it’s the spring.  Maybe the threads or something else.

Try soaking overnight in the Kroil or another solvent.  Use a wrench on the flats and a strap wrench or just your hands on the suppressor.  I think a long time soaking will be to your benefit.

ETA:  This is assuming you have unscrewed the mount and suppressor from your rifle.

Update:  I finally got the damn thing off.  I soaked it in SiliKroil for about 24 hours, put the wrench flats to the mount in my vice, heated it up good and hot with my propane torch, tapped around on it with a hammer, put the rubber Bowers SupCov back on halfway and twisted with all my might.  I'll be getting some copper or nickel anti-seize to put on all my mounts before I put it back on any of them!

I have that same can/mount, but mine has never been stuck.  I would have tried the reaction rod holding the barrel and a strap wrench on the suppressor.  I've had good luck in the past with strap wrenches and some penetration oil.  Thanks for sharing this.

I tried that route as well.