Which bullet for a mag-fed 338RUM?

slm9s

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Nov 13, 2008
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I'm having a 338 RUM built for LR/ELR. Defiance long action, Kreiger 30" barrel, LA Mcree's stock with their mag. I don't think I'll use it for hunting, just banging away at far away targets for fun.

I know I'm going to run into OAL issues, I'll have to balance bullet weight/bc vs taking up powder room in the case.

I was thinking 300smk's because they give great weight, very good bc, and are much shorter than the 300 bergers. But, when I made one mag-length, its AWFULLY deep in the case.

Anyone else go through this and have a better suggestion? 250 scenar? 250 berger OTM?

Or, is it just a lost cause to be mag fed with this system and I should tell my builder to throat it to feed 300's single-shot style? Or, is there a much longer mag system I can use? I could change stocks/dbm if it would solve my issue.

Thanks.
 
slm9s

Sounds like a nice rig you will have. I am running the 300 gr Bergers at 2,750 fps with 92.8 grains of RL-33. Barrel is 26.4 inches. Cartridge COAL is 3.790". I can fit one of those in the mag since it is a hinged floorplate style and the tip of the one round fits just above the feed ramp which effectively makes the magazine longer for that one round. The case is full of powder so that is all it will do. I have thought of throating it for the 300 gr Bergers which I figure would get me to 2,850 fps but... I'm thinking that the elk won't know the difference so probably won't do it. The other reason to not do it is this gun shoots the 210 TTSX lights out and I don't want to mess with that.

In your case with a 30 inch tube, you should be able to get 2,850 fps with the 300 grain pills without special throat and maybe 2,950 fps with throating. If you are just out to have some fun, faster is more fun! Shooting single shot is no big deal at all if you are just punching paper.
 
I have run the 338RUM with the 300smk out of a standard McRee chassis. It was a pain as you stated due to the mag restrictions but it is doable. There is a ton of powder compression but it worked.

I would opt for the 250's if I had to do it again.


t
 
The 250 Berger is significantly shorter and shoot very well in all the 338 RUM's I've built and they mag feed well but if it's strictly for ELR targets you gain much more by seating a 300 Berger correctly and single feeding than you will by mag feeding any bullet.
 
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