what is happening with the red follower mags is this, Number one they suck, let me explain why.
during recoil, there is a heck of alot of crazy force being applied in every which way to everything on the gun. one of these forces is the muzzle flip (i know witness/cz= slide in frame design, not much, but it is there) and the muzzle flip, forces the rounds in the magazine to nose dive really quick and come back up and all should be well (in a well designed mag, at least) but in the case of the "red follower" the poor design of it, it tilts, and hangs up and does not get the rounds back up against the feed lips with proper tension quick enough before the slide strips one out (or tries to) and then the round being rather leval instead of pointing up at the ramp, causes the classic nose dive jam.
couple this with a heavier recoil spring, and the slide is going shut a lot quicker than normal, and gives the rounds less time to "line back up" in the mag and be angled how they should. also the stronger recoil springs put more recoil force to the mag as well, and two fold make the situation so bad you (as well as I) will want to take a band saw to the darn gun. ( i told eaa this, exactly like that, "i will take a band saw to this gun!!") but know that it is a mag. not the gun.
and B.S. to eaa for telling you to use Round Nose. who the hell buys a 10mm to use round nose, and then were the hell can you fing "round nose" 10mm's at. all the FMJ's i ever seen have a JHP bullet profile, flat nose FMJ's.
with my new mags, the k10's, i have shot honady 155g JHP's , double tap variety pack (4 different wieght JHP's), winchester silver tips, PMC gold 170g JHP's, and underwood ammo 165g and 180g JHP's and a myriad of .40sw through it. as well as blazer 200g FN FMJ's. not a single issue, other than a somewhat dirty gun.
also finding a "JHP bullet that fits" is also a bunch of crap. at least for the 10mm, who wants to shoot weak .40sw leval factory loads out of it. not i, i bought a 10mm for nuclear bomb type of rounds, the kind that go off, it feels like someone shot you in the face with a potato gun filled with paper towels.
new mags and you will love it.