Hello all. I am new to this forum and look forward to any help I can get. I have a Glock 23 .40 cal. The gun is great and I have put 800 rds through it. I usually shoot Sellier & Bellot ammunition for the range. I have had a problem lately though. The casing has 2 large concave dents along the open lip of the shell. I noticed that it made one small dent in the past, but the last 200 rds have been consistantly damaged. Has anyone seen or heard of this before? The RO at my local range has never experienced this before...and accredited it to the ammo. However Im not sure. If anyone can help I would appreciate it. Feel free to email me if you wish. Thanks