CCI 200 versus CCI 250 Primers

[Chief]

I posted this a few day ago on the cast bullet forum but no one offered any comments.  Figured I'd ask on a couple of other forums.


I finally got around to loading some cast bullets to try in a 375 H&H. I was loading some Nosler Partitions at the same time so I used CCI 250 primers in all the cases. I was real careful not to mix the powders up and only had one powder can open at a time but didn't think to much about the primers. I always check over what I load and that's when I noticed most of the books listed CCI 200 primers for the cast bullets. These are the first cast bullets I've loaded for the 375 H&H. I don't like playing around with unsafe pressure problems so I figured I'd ask you guys the question if I loaded up something I'd best take apart and use it as a lesson learned. To my thinking these loads should be very very mild compared to what a partition takes but...one can't be to careful. I don't get to the range much these days so I'm not pressed to use them. I just hate to take them apart unless there's a real need. Here are the loads:

43 grains of IMR 4895 pushing a 264 gr. 375449 GC cast bullet.
45 grains of IMR 4895 pushing a 264 gr. 375449 GC cast bullet.

I had planned on shooting the lower charges first and look for any signs of pressure, leading or accuracy problems and then try the 45 grains. Any comments would be appreciated. Thanks.

[JJFly]

I wouldn't fret over the primer mix.  There isn't that much pressure difference between a Magnum primer and Standard.  I've tried interchanging through a load development.  Noted the magnum primers are nearly always necessary for powder charges over 50gr to keep the shot to shot deviation under 20fps.  IMHO I think you'll maybe see 35 fps difference if you ran the same load again with standard primers.  If you're uncomfortable, load 5 standard primed cases, charge, seat bullet and shoot them first and see how it goes...

My .02

[gunnut69]

I've pretty much always used the mag primers for the slow burning rate powders in large cases and the standards for everything else.  Then I was developing a cast bullet load in a 44 mag DanWesson.  The pistol loved 300 grain Hornaday XTP's but with any cast bullet load I could think up or find it shot like the pits!! 6-8 inch groups at 50 yards.  The Object was a lowered velocity load for practice and small game.  I tried many different custom cast bullets and powders and charges from everywhere.  Then one day I read in a magazine of a man with the same problem in a colt 45.  He tried mag primers and the problem was gone.  I loaded up a batch with a 240 grain cast BB semi wadcutter and a mild charge of Unique..  The results were astounding!!!  It would just chew out the x-ring.  Groups were under 1 1/2 inches at 50 yards.  It will shoot sub 3 inch groups at 100 yards with a bushnell scope..  I'm not sure of the reason but believe the hardcast bullets were not upsetting well with the lower pressures of the standard force primers and the mags created a bit more initial pressure to help them retain a better gas seal..  I've shot a bunch of light loaded wadcutters with standard preimers and had no problems at all but wadcutters are not likely cast hard...