I have found holsters that have worked very well for me in the past and did make a mistake at one point, after picking up a Glock 19 and thinking my Don Hume Jit holster was going to work just as well for that firearm as it did for a Sig 239. It fit just fine but the gun did not feel as balance in this holster type and it seemed to swing a little too much. Movement with gun holsters is something that should be avoided. I have often taught students in classes where the first thing we did before we went to the training range was to try running 100yds and back and feel the movement of their gear and get rid of the stuff that didn’t stay still.
Gun magazines and radios should not move one bit and any gun that has play in it has the capability of not being where you want it to be if you tried to grab it. The Desantis holsters that we sell to customers that fit this criteria are the Desantis Scabbard holsters. These holsters will keep your gun securely up against your body and not bobble about. There are many operators that improperly deploy secondary sidearms with the holsters they use which often comes up on day one with leg holsters.