I've shot many 300 Win Mags, and currently own two. Admittedly I don't shoot either very much although like to keep proficient. I guess the calibre is a little surplus to my needs currently but I'm reluctant to dispose of the rifles...one never knows, China might arrive in numbers and I'll get to use it.

Keep up the dry-fire, it is one of the best ways to work on the shooting process and will increase your performance when things get loud.