Top cover opening after firing on M53

[bmwr12]

I have a Wiselite M53 that had a Yugo top cover originally but I changed it out to a Mg42 Top cover. The gun works great except for when I switched the top covers out. The top cover is popping open when firing blanks. I have not fired live ammo with the WW2 top cover. Any ideas?

[Folke]

I have a Wiselite M53 that had a Yugo top cover originally but I changed it out to a Mg42 Top cover. The gun works great except for when I switched the top covers out. The top cover is popping open when firing blanks. I have not fired live ammo with the WW2 top cover. Any ideas?

The spring for the top cover latch is too weak. Blanks generate a lot more pressure than live rounds.

[DARIVS ARCHITECTVS]

The latch may not be fully engaging. M53 top covers vary in length compared to German ones. Sometimes you can't even get a swapped out top cover on. They are NOT truly interchangeable because of wild tolerances. If you get one that fits, you're lucky. If the cover is a bit short, perhaps your latch is not engaging and grabbing enough meat on the receiver. Take a closer look.

[fritsch]

+1 to what DA said. I'll bet it's not grabbing enough meat on the receiver. Does it click down really easy? If that is the problem, you can dab a little metal in with the Tig. If you don't have a welder, get a new top cover and hope you get one that either fits or is too tight. If it's too tight, just file the latch or the receiver to fit.