BLUF/tl;dr: shooters with experience using both GI and KCI mags in M1 Carbine, is shiny new KCI or rusty GI better?
I recently took possession of an M1 Carbine. The magazine situation is not great: I got only a few mags to go with it. I scored a handful more old GI mags with big nasty rust spots all over them, but some sand paper and black rustoleum rehabilitated them nicely.
I am planning on a second purchase. I scoured all the forums with relevant threads, read reviews, hit up all the YouTubers with related videos, and drew the following conclusions: 15rd GI mags are consistent and reliable but (maybe?) not very durable; the 15rd KCIs (new production Korean) are reliable; the Old Tiawanese 15rd mags are excellent but unobtainable; the new Tiawanese mags are bad; the original GI 30rd mags are good but unobtainable at any reasonable price; the KCI 30rd mags are not a safe bet (some are reliable and some are not); any ProMag (15rd or 30rd) is an absolute no-go.
While most places are sold out, I have found a few smaller outfits with the KCI 15rd magazines still in stock and one with the same outside-rusted GI mags.
I want this weapon to be a practical PDW for a family member (woman or teenage boy) to use in an emergency, not just a fun shooter, so reliability is big.