Re: 338 RUM Magazine length ?
I'd say it would depend upon your magazine length. Is it a 3.60"?
I rebarreled a 338 win mag Beretta Mato(which has a mag length of 3.685") to a 338 RUM and had the smith set the throat so that I could seat a 225 gr Accubond OAL at 3.600" and have a .020" jump to the lands. My main load now is a 225 gr TTSX which has a OAL of 3.580" and is .050" off.
A word of caution, if you set the lands at a shorter distance in order to reload closer to the lands, you will have a combustion chamber smaller than factory guns. This will mean that you will not be able to load at book max. If I use a charge of 98 grains RL25 (book max for 225 gr bullets) then I lose the primer pockets, so I am now loading at 94 grains. IOW, start lower and work up.
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