I wish we had a "semi autos" only section as most of my question will all now relate to the semi auto builds done here in the US. I doubt many other locations are doing them, meaning what other country around the globe would have the legal and financial emphasis on doing such a thing?

My L4 has been experiencing quite a few bolt over base jams. I do not necessarily think they are all induced by lack of gas, meaning short stroking, BUT THEY COULD BE?? I feel like the mags themselves may be allowing the cartridge to be stripped, but either not feed correctly (possibly due to mag spring issues) or possibly a short stroke due to the added spring used to drive the separate striker in the firing system?

I have been experiencing this and have not come to a completely satisfactory solution. I did try stretching the springs out a bit to get a more positive cartridge to feed lip interface. That seems to have worked on one mag, giving me a full 20 round feed without an issue, but not successful with all mags. Of course, added spring pressure on the cartridge would only mean more stripping power is needed from the drive springs.

With these semi auto rebuilds, it seems to be such a delicate balance between drive springs, striker spring and magazine spring to get the whole thing running properly. I am suspicious that having the 3rd striker spring in the system may mean that the gas needs to be opened up a few thousandths on the largest setting, because not even the largest setting is giving complete reliability.

Are these magazines known to allow bounce of a cartridge so that it may start to feed, but somehow the feed horns get off the base of the cartridge and slam into the partially fed case jamming it between the bolt and the chamber? Just curious to see if this event EVER occurs in the full auto L4??
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