I also shoot a 7-30 Waters in a 14" Contender. A couple things I would check. First if you have a loaded round of ammo, compare the OD measurement of the neck between a loaded round and a fired case. Will give you a idea how much the brass is being worked in the neck area. Also, if the fired case is say, over .008" larger than a loaded round, you may want to try and get a accurate measurement of the neck portion of the chamber. This is a lot easier than on a bolt gun with a action attached. What I am getting at is if the neck portion of the chamber is "large" or the sizing die is sizing "small", the brass may be work hardened enough to cause the cases to crack with even a load nowhere near max. The 7-30 Waters is a fine cartridge and very effective. In parts of MN they area legal in shotgun zones. The first time I showed up with 7-30 Waters Contender, I almost got laughed out of a deer camp. After dumping a nice buck at 180 paces from a sitting position and shooting sticks, not much was said. The next year, half the camp had some sort of "long range" pistol. LOL. Also, not sure if you are familiar with Mike Bellm. He sells a variety of T/C related components and services. After reading and understanding his concepts for reloading ammo for the T/C platforms, my life got WAY better and accuracy/reliability improved greatly. I highly recommend checking into the info section of his website. If you have any other specific questions, don't hesitate to PM me. Cheers!