[Jimski]

hey all,
I replaced a broken magazine lip on a KJW magazine, but since then it doesn't cycle properly, like there is not enough power output.
It does the same thing with two different replacements parts.

since it's the same with both parts I'd figure the problem comes from the mag's shell, but there's nothing I can see...

I tried sanding a little on top of the lip where it touches the nozzle, I thought it was rubbing against the nozzle at blowback time, but apparently it's not that.

any ideas?
thanks a lot!