KCI mag question regarding bolt hold open

[Bruce McAskill]

It was about mid 50's that Springfield Armory started to Parkerizing magazines. While they did many thousands of them it was a drop in the bucket. All to try and reclaim new unused magazines that had started to rust in their original packages. This is most likely when they replaced any bad followers with new production ones and those being the cut off ones for the M2 magazines.