Keymo is bombproof and IMO very safe and convenient.

I never noticed the weight that much but I would notice if my can came loose during firing or got stuck when I wanted to take the can back off.

You do have to rocksett the shit out of everything but even when I didn't do this, all my failures (ie, stuff coming loose) were during disassembly rather than during shooting.

I've run direct thread before (primarily on 22 hosts/cans) and it's annoying during extended shooting sessions when stuff starts coming loose.