My buddy just gave me more than 200 nickel plated once fired cases for .300RUM. Mostly Remington but a bunch of federal too. This is the kick in the ass that I needed to get into reloading. I have a .300 RUM on order which will one day be an edge I hope. Anyway, since the brass is fireformed to one gun, is it possible that it will not fit another? Expect a barrage of questions on reloading in the near future. Going to get a RCBS kit and a good book if I can find one. Any other advice for getting into reloading is welcome. Does everyone measure headspace? What kind of tool do you use? If I understand correctly, you have to cut the brass down because it grows, and you want it to be a certain distance from the lands? Too much distance causes case growth, too little can damage chamber? Last question, what is the heaviest bullet I might try for the RUM that will fit a factory magazine? I am looking for a bullet that will perform well on game from 100-800YDS. I realize that I will probably try many over time but looking for a good place to start. This forum rocks. I have learned a lot here and now I finally have the tools to take my shooting to the next level. Thanks.