Is it practical to underload a 300 rum?

[Fierce300rum]

I have a new fierce 300 rum. I'm also new to this site and reloading. So my problem is my rifle came with a target from the factory and the load they worked up looks good on paper. But the loading data says they used a 185gr vld with 80gr of imr 7828 and that is 5gr below what my book says to start with. Does that sound right to anybody? I appreciate any feedback thanks.

 

[Barrelnut]

I have the 1st Edition of the Berger Reloading Manual. What book are you using?

For the 300 RUM with 185 Berger VLD and IMR 7828 SSC the min is 77.5. So according to the 1st edition you are not loading under minimum. SSC stands for Super Short Cut. Its weight is the same as regular IMR 7828.

Berger manual has this:

185 Berger VLD
IMR 7828 Min: 77.5 Gr. Max: 86.4 gr.

You should never load under the minimum. As crazy as it may sound underloads can more dangerous than over loads at times...

It is good that you questioned this. Be safe and have fun. 300 RUM is FUN to shoot!

 

[Fierce300rum]

Thank you very much for your response. I do not have a berger manual I have the nosler 6 manual. I didn't realize the info varied so much between books. Thanks again.

 

[Barrelnut]

Yea, it can vary a little more than you might expect sometimes. Different bullets, even of the same weight, have different external dimensions. Lots of times it is the bearing surface length that can affect pressures. Also the brass used can affect the published loads. For the example, Nosler brass is thicker than some other 300 RUM brass. So it has less internal capacity and uses less powder to reach the same pressure. That may be why the Nosler book list a lower load. Another strange fact is that the Berger manual is published results from a program called Quickload. It is a highly requarded program though. It is speculation, but if you look at the Berger manual, they don't list the brass or primers used during load development. Welcome to reloading.

 

[Frank in the Laurels]

Shoot it over a chronograph, don't assume it's way under what you thought it's velocity should be...you might be in for a surprise either way. With that cartridge and bullet your ready to take on anything that walks in North America !!