What mags do you use? They should have bit of spring tension on the slide stop when they run empty so they should kinda "shoot" out. Some mags won't do that though, my brother has a compact Sig and if it's not pointing exactly down he has had to pull the mags out. My main problem in reloads is getting a hold of the new mag quickly and correctly.
The instructor had 2 of these moving targets on the pvc pole. I shot them both in half. We cobbled them back together and I shot one apart again. I was glad someone else broke the last one, it was getting embarrassing.