form RUM cases from 404 jeff

steve smith

Well-Known Member
Jul 4, 2001
San Antonio, Texas
I got to looking at reddings form and trim dies the other day and made an amazing discovery. You can call me genius. By using the 375, 338, and 300rum form and trim dies (about $23 a piece)+ a fl size die you can form the RUM cartridges easily. The only other option I have seen is RCBS form and trim dies for the 300RUM, and the cost on them is about $250, and you still have to buy a fl size die seperate. I bought the 375, 338, 300, and 7mm form&trim dies for about $100, and with a thin film of Imperial sizing die wax it works great.
Remington didn't do anything that hasn't already been done for years in necking down and forming the 404 brass. That's why the forming dies are already out there. All they did was add a rebated head onto a 404 case, changed the overall length a little, and called it their RUM case. So are you turning the 404 brass heads down then to fit into your .532" bolt face?

If you try to make a 700 bolt face larger then you have to install a Sako or M16 type extractor and then you've disabled one of the best safety feautres of a M700 action in my opinion. And that's the ability to seal off gases from escaping backward in the event of a complete case failure for whatever reason. If you cut into the side of the bolt face to fit a different extractor the "3 rings of steel" concept is compromised and all bets are off for trapping escaping gas. Then you know where the gas and shrapnel are coming from in the event of a case failure. Myself being LH shooter and all of my M700 action rifles are RH, I don't have a good feeling looking straight down at a grenade in my face if the worst ever happened. If prefer the Remington extractor even if they do break at inconvienent times. But they are easily fixed also.

I am fimiliar with the Rums predecessors and the fact that Remington is very good at taking others ideas and claiming credit. But they did make it alot less expensive to form the brass. Standardized cartridges mean inexpensive dies.

As for the bolt face. I will have it opened up and a sako extractor installed. Being that I will probably settle on a load that does not push the limits, I'll forget about the three rings of steel pretty quick.
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