The best way to find out if they're dependable is shoot with them. I've converted my G35 over to 357 Sig and I own a G33 as my daily CCW. I have noticed that I can get one extra round in all my .40 Glock mags, so maybe if you want to change followers go with the .40's. It would be less of a pain my friend if you got a Glock mag disassembly too or else you may be cussing at all the damage you end up doing or at launching the spring and follower across the room and into a very hard to reach area (personal experience heh)