Four mags with 28 rounds, one with 30. The mags are all surplus in NOS/unissued condition. I have some other surplus mags that look extremely beat up and have worked perfectly but I haven't done the storing-while-loaded test with them.
Thanks! One last question -- did you test fire before loading?
I shot the four mags loaded with 28 rounds first, all without problem, then shot the 30-round mag, which is the one that had a minor hang up with chambering. All five mags have been in regular rotation for years. I did see in my notes that the rifle had a similar, solitary minor jam long ago, so it may be the rifle, the mag, or just a coincidence.
I specifically pulled out the mag loaded to 30 to test as I was rearranging my gear and noticed that the right feed lip was askew. I don't know if it was like that when I got it, or if it had stretched from being loaded to 30. I haven't tried to correct it yet. The test I did with the mags loaded to 28 and the one to 30 was the definition of unscientific. It was an afterthought as I had no specific plan to do so when I loaded them years ago. I tried to imply that uncertainty with words like "seem" and "could", and I apologize if it came off as a rigorous process. I vaguely remember reading on this board or elsewhere a Bonesteel post in which he said the magic number is 29 rounds, and that he had noticed feed lips spreading when loaded to 30 rounds and stored long term.
That Bonesteel post is what caused me to load the mags to a more conservative 28 rounds, and that post may very well have colored my perception of the recent impromptu "test". Of course, to do it right would need direct intent and then waiting several years for resolution. I'll be interested to hear your outcomes.
