Now I know Lemmy’s airsoft community is tiny, but I figured it’s worth a shot, since I can’t really find anything about this issue anywhere else, even on r/airsoft.

I have a CZ SP-01 GNB pistol, and lately it’s been having an issue where the gas output when firing would be very inconsistent.

Its worst point was usually when first firing the gun after either inserting gas or not having fired it for a few minutes if gas was already inserted. The gun also had gas issues outside of those circumstances, but not to such an extent.

I’ve disassembled the gun completely to look for any issues, but couldn’t find any, and even after reassembly the problems persisted.

This makes me think the issue might be inside of the firing pin chamber, which is the only part you can’t disassemble, as the firing pin is inside of a welded plastic housing.

The gun’s basically useless as long as this issue persists. Have any of you had a similar thing happen? I can provide images and video of the gun in question if needed.

EDIT 1: Here are the images:
all internal parts
assembled mechanism: right side
assembled mechanism: left side

magazine gas seal

a picture of the whole gun taken from the internet: right side
same as above but left side (this one in particular is chambered for airgun pellets, but the external appearance is identical)

dry firing the gun in slow motion
the gun firing correctly (filmed while trying to film it firing incorrectly, oh well)

EDIT 2:
The gun works perfectly fine now. Not sure what happened. Just ran through 8 mags on one cartridge without any major issues.

I will confess that the gun hasn’t had proper maintenance in a good while, and it’s likely that fully disassembling, cleaning it, and reassembling removed some gunk (probably from old lubricant) that was stuck in the firing pin chamber, which made it run smooth again. I have no clue if that’s what actually happened, it’s just a theory.

EDIT 3:
Nevermind, the gun is alive and it hates me. Started malfunctioning in the same way just now.
Lubricating the magazine feed rail did not help either, so I’m basically out of options that don’t involve taking apart the firing pin or replacing the hammer spring.