I'm not a tube gun expert.
My friend's MK-760 (clone of the Omega Man's SW-76) is having some feed problems.
The firing pin hits ***very deep*** when it hits, so we know the firing pin is not the problem per se. These are known for poorly built firing pins made of soft metal that peen themselves down and cause light primer strikes. When it malfunctions, there is an ever so shallow mark on the unfired round.
After doing some research, it seems that the magazine tolerance on these is VERY close to the point that the magazine feed lips may be touching the bolt sometimes, causing feed issues. I have some Suomi magazine conversions we're going to take along to see if other magazines suffer the same problem.
It was about 30 degrees outside. I'm not sure if cold cold weather can affect the performance on these tube guns... it wasn't the cleanest weapon I've ever fired... is it possible some grease was thickening up and causing the action to hang?
Curiously, the Wolf 9mm we used seems to malfunction the most. Both stovepipes and failures to fire. It seems as if the striker is not resetting. Every single one of the rounds that would not fire in the MK would fire fine out of my Uzi. So we know it is not the ammo.
When we used some reloaded 9mm, we got consistant performance with only some stovepipe issues.
Are we missing anything? I'm taking the power inverter and dremel with me to make on-the-spot mods at the range.
Based on previously published info, we're going to examine the magazine and sand those down if they are contacting the bolt.
We gave it a THOROUGH cleaning so we can rule that out completely. The blowback on this one really fouls up the magazine and chamber, more so than even my Uzi!