Just wondering if anyone was using accurate xmr-3100 in 300 win mag. I have a couple pounds of it sitting aroung collecting dust and though about trying it. According to several reloading manuals, 75 gr. is max with 180 gr. bullet, but reported velocities were only 2950 fps or so. This seems low, as the burn rate lies somewhere between IMR 4831 and 7828. I don't own a chrono(yet), so I am interested to hear if anyone has chonographed this powder/bullet combo. Thanks.

I bought an 8 pound keg of MR-3100 when it first came out. I still have maybe a third of it. It was being advertised at that time as being nothing more than surplus IMR 4831. I do not know about that, but the loading data is very similar.

I tested it in a Remington 700BDL chambered in 300 Winchester Magnum with a 24 inch barrel. A charge of 74 grains of MR-3100 with a CCI 250 primer and a Nosler 180 grain Solid Base gave a velocity of 2939 fps over my Oehler chronograph.

Hope this helps.

If this is AA-3100 (now MRP) that you are talking about........

I tried loading 308 Win with it and no matter what charge I used, I ended up with unburned powder left in the case and the whole length of the barrel!
I works fine in my 7mm Rem Mag and my 7mm-08!
I was told that the 30cal was over-bore and therefore the MRP wasn't a very efficient powder for it!