Quoted:
The curved are from two places. They are not factory.
4 of them came from CTD. I have had some success with them on pistol mags but for some reason they have problems with rifle ones
4 of them are asian(?) contract. They look just like the other ones. No markings on them. I will double check the feed lips/mag catch area. Thanks in advance for those helpful hints.
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Here is the deal on the asian 40s, the srpings are fricking strong.
On a REAL HK this is not a big problem.
If you compare a HK bolt to a SW bolt you would nitice the HK bolt assembly is much heavier being made from a higher grade of steel. The weight of a REAL HK bolt combined with the heavier recoil spring can manage to feed off of the asian mags.
The SW bolt being lighter, and with a weaker recoil spring will not. This is why it is literally not strong enough to strip off the next round out of the mag. Putting in a genuine German recoil spring will not solve your problem either as the SW bolt is not heavy enough to cycle against it.
Despite claims, SW is not spec and parts will not interchange with HK parts and still work.
As for solutions you can try and break them in, keep them fully loaded to weaken the springs over time and just use them as 30s at the range.
I also know a guy who shortened the srpings to make them a little weaker so the lighter SW bolt will be strong enough to strip the next round off.
You're Welcome.