I've been shooting the .300 RUM since its introduction in 1999. Now I shoot the .300 Norma Mag. which IMHO is a far better cartridge for hunting or target shooting. Any of the seating depth problems are negated by the shorter case allowing these longer heavier bullets to be seated out to magazine length. The standard long action magazine work just fine without having to cobble up the action just to use a longer magazine box. I run both the fixed internal boxes as well as the DBM systems for hunting and target shooting.
The .300 Norma Magnum has been adopted by the U.S. military so none of the lists will stand up for much longer. As with the .30-06, .308 and the .223 previously, the supply lines will fill up given the ever increasing demand for new brass, cheaper manufacturing and the surplus supply in support of a newer military cartridge. That's just the way things play out. Besides, Norma, Lapua, Hornady and Peterson already make brass with other makers in development. The retail ammunition will follow along quickly enough as the demand outstrips the supplies. Reloaders are sitting in tall cotton given the selection of .30 caliber bullets and magnum capacity powders.
If you still feel undergunned, call one of the reamer makers and order an improved version of this cartridge. I went with a 30 degree shoulder and slightly blown out sides for an increase in case capacity and slight improvement in powder selection.
There is plenty of reloading data online currently, more than enough to get someone started on the right path to load development. If you can't find that starting load for that one super special combination, start a topic here or elsewhere to get some information.
Enjoy the process!
