stan, why are you using Titegroup in this caliber? Are you trying to develop a load that isn't a true 500S&W Mag? More like a 500S&W Special? The reason I ask is I did the same thing. I had a Handi-Rifle in this caliber and it tore the snot out of me every time I tried to shoot it with full power loads. I started looking around for some other loads to lighten the recoil.

I did try Titegroup and had modest results but I was shooting light for caliber bullets too, 325gr Gold Dots. There is no way that you should be experiencing this kind of problem unless you are either overpressure or there is something wrong with your gun.

Using CCI primers MAY help but it still doesn't really solve the problem. Maybe the firing pin bushing is shot and needs replaced. Maybe the load you have is too high of pressure. Is it a published load? Did you verify from more than one source?

Just some questions I would be asking myself if I was experiencing the things you are.

Hope this helps.