I had the same problem. I just kept flexing the holster frequently (anytime I went by it) and stored the gun in the holster when I was not carrying the gun. Pull, tug & twist it a bunch to help loosen and stretch it. I've heard about using water on the tight areas, but I was hesitant donig that, IMHO. My Beretta fits well and the thumbreak strap will now operate properly. Took a good 2 - 3 weeks, though.