the 300 RUM is the very reason I got into reloading. After I bought 2 boxes of shells and it was $35/ box, I decided to get into reloading them. There are a number of guys on here that reload for this cartridge and can assist you in almost any question you have. Bigcountry, Stubblejumper and myself to name a few. Check the reloading forum for a few threads on getting started into reloading, there is some great info in there. The main difference in reloading for the 300 RUM compared to most regular rounds is the overall length. Rather than trying to get the bullet close to the rifling, your magazine dictates how far you seat your bullets. As long as you can fit it in your magazine that is your oal.