I called CCI this morning and the gentleman I spoke with said that in my climate the worst that will happen is the velocity will be down maybe 100 fps, but the 300 primer will light 23 grs. of H110.

I'm going to use these loads to break the barrel in. I'm wanting to go with cast bullets with this gun, and I'm going to lap it in, then after that finish breaking it in with these jacketed loads, just like I break in a new stainless rifle barrel....shoot one and clean for 10 shots, then shoot five shots, then clean, etc. I want to get the barrel consistent in size and smooth.

The bullet I plan on shooting the most of after that is the .432" 240 WFNGC that Montana Bullets sells, with about 10 grs. of Unique. (My throats measure .4325")