To the question at hand, if a magazine doesn't function properly and you have some basic mechanical ability, many can be tweaked and otherwise coerced into functioning
Yep, never had one that needed a break in period but plenty that developed or had mechanical problems and most of them were easy fixes. My oil soak, clean and run the follower up and down a few times routine corrected most problems, they were just gunked up.
Good intentions will always be pleaded for any assumption of power. The Constitution was made to guard the people against the dangers of good intentions. There are men in all ages who mean to govern will, but they mean to govern. They promise to be good masters, but they mean to be masters.