44 mag ammo

I have never had any problems running SP 44 mag rounds through the rifle as far as deformation goes. The soft part of the "sp" isn't all that soft.

If it is hitting your breech hard enough to deform, you have a feed ramp problem. You would be more likely to be recessing your bullet(sinking it deeper into the cartridge) before it would deform. Like usmc1371 said, They are not really that soft.