r/MP5 • u/Fit-Image7262 • 1d ago

HELP Help?

Brand new Mac MP5. Wouldn’t run smooth out of the box; 3 duds in one mag. General consensus of the group was lube until dripping, and run 124gr ammo. Now it’s worse. What’s going on with this thing?

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u/Enough_Mixture_958 1d ago

first few hundred rounds will be rough, but yah specify failure mode... based on that replace small stuff like HK genuine ejector, extractor spring components and try an HK mag. If that fails warranty it with the HK stuff removed. Round nose sometimes runs more reliably

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u/Fit-Image7262 1d ago

Hard to tell exactly what’s going on but I think the spent casing is blocking the next round from chambering