It’s the UltiMAK model M15 optic mount for the Yugo/Serbian M92 (A.K.A. PAP) AK pistol.
There have been a lot of requests for this. The first batch went into anodizing today and should be shipping by next week.
As always; yes it’s slightly shorter than the original piston tube. Yes, it’s supposed to be that way. No, that won’t have any effect on carrier cycling whatsoever. Yes, it’s the very best place for a dot sight on your AK. It’s also the right place to mount a pistol scope. No, it doesn’t need to be removed for cleaning.
I won’t get into the issue of the utility of an AK pistol. Several of the guns I own don’t have much real utility in the strict, modern sense (the reproduction 1861 Colt Navy percussion revolver comes to mind). Then again, some people are SBRing the AK pistols, providing a sub-gun-sized, shouldered shooter with a lot more power (and muzzle blast) than a 9 mm or a 45, plus ammo and magazine compatibility with a regular AK carbine.