Large Rifle vs Large Rifle Magnum primers

I'm in the process of building a 30 Sherman Magnum (a 300 PRC Improved). I have a pretty good supply of 210M primers but no 215M's. Have any of you run into any issues running a standard large primer in a big magnum instead of using a magnum primer?

Hmmmmm....what is your powder weight? You have to be careful not following the book? Mag and standard primers have very different results. If powder charge is less than 300prc then maybe. If more, you need 215. Good luck.

It will work, but it's not ideal. Not sure about case capacity of the Sherman, but by taking a glance at PRC load data I'm going to guess it's close to the capacity of the 300 Weatherby magnum. The magnum primers were developed years ago at the request of Roy Weatherby to light the enormous powder charge of his new 378 Weatherby, which has about 1/3 more case volume than the 300 Roy.

You probably will not have any ignition issues, with the possible exception of cold weather. This can be an issue in extreme cold, so some Northern loaders sometimes use magnum primers in standard cartridges like the 30 06. Without knowing the case volume of the Sherman, I'm guessing it's at the top end of what I would be trying to light with standard primers.

JMHO.

Thanks for your comment. It uses a charge weight in the neighborhood of 81 to 83 grains of Retumbo behind a 230 grain. Maybe I can land some magnum primers by the time my dies come in from Whidden.

You can get magnum primers on gunbroker. You just have to give up the $$$$

You will get incomplete powder burn with that much powder stick to LRM primers they are out there just have to be quick to get them