Dissapointed with my new Gemtech 9 Multimount....

[ChrisNCT]

I got a chance to take my newly transferred Gemtech 9mm Multi-Mount suppressor out with my new Heckler & Koch USP SD 9mm Tactical Pistol. I expected awesome preformance but after 3 rounds I was very upset.

I experienced first round hit at a 35 yard target and after that random fliers on every shot. I was using Winchester 115gr. FMJ "White Box" ammo. I adjusted the LID into the different slots after couple rounds to see if there was any improvement. None at all.

I then removed the suppresor and shot 9 hits at the same target at the 35 yards.

I can understand point of aim & point of impact shift from can on/off but damn... these fliers were like 4feet to the right, 2 feet higher, 1 foot lower.

I am planning on taking it to the range with my 10.5" 9mm Dedicated AR15 SBR with the 1/2-36 thread mount installed to see if it is the can.

Any suggestions?

[doubloon]

Make sure it's not backing off the host after a few shots?

I have the 9mm M.M, shoot it on 3 different hosts with tight groups that never shift.

[ChrisNCT]

Yep..can is tight on the barrel.

I dont see any issues looking down the barrel from chanber end all the way through the can. I also dont see anything that would be out of place nor do I see any dents, rubs or anything that would resemble impact inside the suppressor.

Here's some pics:

Host Gun

Muzzle Threads

Look through the Suppressor at baffles

Blast Baffle

Blast Baffle

Blast Baffle w/ L.I.D.

L.I.D.

Suppressor Endcap

Looking into the Barrel Chamber through the Baffles

Barrel Threaded onto Suppressor

[Kramer]

I have the 9mm M.M, shoot it on 3 different hosts with tight groups that never shift.

Same here, never had a problem. I was going to pick up another MM because I have so many mounts and hosts.

I would try different ammo as well, try to find 147gr or 124gr and see what happens.

[doubloon]

Can looks unmarred ... what is that sand looking stuff on the blast baffle? Not that it should make a difference for your problem just curious.

Take the piston apart look for something strange around the spring? Maybe it catches/twists/kinks? Clean it grease it?

Have you found a buddy with a pistol host you can try it on? It would be interesting to see if the problem follows the can or the host.

Good luck.

[JohnInNH]

The yellow "sand" is Winchester powder residue.

It looks like you are already getting erosion in the 3rd baffle ... Keep a close eye on the baffles when using Winchester Ammo. The Winclean eroded my Evo-9 baffles VERY fast. A flake powder will work better. My Evo has eroded at the 2nd 3rd and 4th baffles a LOT. See my Baffle Erosion thread.

What's going on with the threaded end of your piston? Looks like a ding there. Maybe if it has a ding in the part that mates to your barrel shoulder it is seating on the barrel canted a little off and causing baffle strikes. It appeared to be doing that from your pics unless that's erosion from the sandy powder residue.

Another thing to look at is to make sure the fingers of the piston are seating flush inside. If there is crud in there under them it will cause issues too. Make sure it is seating correctly (Push in and rotate the silencer back n forth the 1/2 a deg of play it has to help make sure the piston is flush and seated 100%

It is hard to tell from the pictures.. But that's my guesses.

[ChrisNCT]

Hi John,

After reading some of the info posted, I checked the can today.

1) I'm glad you told me what those little yellow things were. It had me baffeled.

2) I shined a light into the baffle stack and all I see is carbon. Very little to no erosion. I think the pic doesnt really show what I see with my eyes.

3) I think it was something on the piston. There is no dings or dents around the opening. Now you got me wondering what the heck was on the piston when I took the pic.

4) I took the LID apart and looked to see the corner where the piston seats in the forward position. No buildup but it is darkend with little carbon. However the spring is dry. I will have to look to see what kind of lube to put on it.

[doubloon]

I use Break Free with a little molybdenum disulfide mixed sprinkled into it to thicken it up then paint it on parts like the spring.

I can't swear it helps anything but it hasn't seemed to hurt yet and it makes me sleep better.

I saw that same ding JiNH mentioned but didn't think it looked like a problem, it definitely looks like a chip or like something cracked off in the picture.

But I sure did not see what he called erosion until I went back and looked again, JiNH has a good eye for detail. Maybe it's just the light but from the picture it definitely looks like the beginnings of some light erosion.

Thanks for identifying the "sand" ... staying away from WinClean.

[rat_dogratty]

Try some 147gr and then try another host. My multimount works great on my Beretta and Glock.

[flight954]

I have the 9mm M.M, shoot it on 3 different hosts with tight groups that never shift.

+1 here I've run mine on an S&W M&P Spec Ops pistol(13.5x1 LH TP), Glock 19(1/2"-28 TP) and my Rock River 9mm SBR (10" 1/2"-28TP barrel and 5" TROS 3lug barrel) No problems here with many different brands and types of ammo.

[firefighter509]

Personally ( just my opinion ) it's you HK.

I run mine on my M&P with no problem what so ever.


Sorry not of much help