I just got a new to me Guardian with 250 rounds through it. I shot it for the first time today. I love the gun. It is a tack driver, soft shooting and lots of fun. After about 60 rounds or so, I noticed that the slide was not exiting back after the last round. I was wondering if you guys think it is the break in process, the 12lb spring is too light, or the slide is just slowing down because it is dirty. This happens with the DW mags and a couple I have from my Para Expert 9.