Yep I think it's your volumizer/front grip, I threw one on my cat and I have to turn both the velocity and recock all the way in and back out the main spring quite a way whenever I use Co2. It shoots soooooo nice.
Also Ironnerd88, I'd just recommend picking up one of these from Bacci. I put one on my cat and it made a world of difference ergonomically. Hands down the comfiest mech double trigger I've shot.