Could never get my hybrid .46 silencer with KAW valley tri lug mount to seat on my PTR CT9 MP5 clone.  

It worked on absolutely everything else I tried it on.  I fluffed and buffed the KAW Valley mount AND the PTR's built in tri lug adapter , removing the finish AND some metal from my PTR--still didn't work.  More smooth to be sure, still didn't lock.    NEVER able to get through to PTR, even when leaving vague OR detailed messages.  Even for Rocky. Email or phone.   So I have bad mouthed PTR a bunch.

So I decided to try a different mount, a Silencerco tri lug, and it worked on ALL of them, including PTR.  So I got a second Silencerco tri lug for my other Hybrid, a new adapter for my Scorpion, GHM9 and others (so mixed brands) and BOTH Sico worked on ALL, including the PTR.

So it was the KAW Valley tri lug  mount that was off, not the PTR adapter.

So in the spirit of passing on knowledge and correcting some of my comments on PTR, you have this thread.

Good on you. As a person who owns 3 PTR's I have to say their customer service is atrocious.

I have a KAW valley mount that doesn’t fit my POF, but chalked it up to the POF being shittier than other clones.

Bought a sico mount that works fine.

I went with a YHM 3-lug on my Hybrid and it works fine on my PTR.

It's not great. Good thing my 9C has been flawless because I'm not confident they'd be in any rush to do anything if it broke.

Resilient tri-lug adapter fits on my PTR 9CT-CL just fine.  Now if my OCL Lithium would just get out of ATF jail.