I have always owned revolvers other than a couple of .22s. When it comes to long guns, let's just say I think Jim Zumbo got a bad rap.
At any rate, bought my first center fire semi auto pistol, new, and found that the magazine springs are extremely stiff.

Load them and shoot them. The springs will loosen up.

Sorry, gejohnston, but your agenda is showing. How about explaining yourself?

when it comes to handguns. There are a number of practical reasons for this, none of them having to do with politics. One is reliability when the wilderness during Wyoming's arctic like winters.
so this is my first semi-auto pistol purchased new. That also means new magazines with stiffer than shit springs. That is my explanation. I'm not a collector nor a hobbyist, so I don't claim to be and expert.

Sorry I can't offer any tips on semi-auto magazines. Perhaps some private messages to participants in the Gun Control/RKBA group would be beneficial to you; Lord knows that semi-autos are popular, over there.

Cycle through them a few dozen times at the range....or load them to capacity and let them sit for a few weeks....in a secure manner of course.

A good magazine doesn't need a break in for functional shooting purposes, but doing one of the above will make them easier to load by hand.