I have a glock 19 with a lasermax sight that I recently got. Gun worked perfect the first time at the range (100 rounds) when cleaning it after this first trip I accidentally lost the end cap after it went flying. I ordered a new end cap from lasermax and took the pistol to the range today for the first time. Now, the gun locks the slide back after every round. Even after inserting mag and trying to rack the slide, it tries to lock back the slide as if there is no mag. Any ideas? Did they send me the wrong end cap? Does that even matter? I appreciate any help.