300 RSAUM & 210 grain bullets

[bjld]

Hi all

I'm building a 300 RSAUM with a 28" barrel and want to shoot 210 grain bullets.

Berger states a 1:11 twist for their VLD and Sierra a 1:10 twist for their MatchKing.

Will a 1:11 stabilize the Sierra?

I'd like to use the slowest twist and trial both bullets before settling on a load.

Any suggestions for powders? H2213SC? H4350?

Would a magnum primer be best?

The 284 Winchester isn't much smaller and seems to do well with a standard LR primer.

TIA
Ben

 

[Charles E]

Edit:

I just checked Wikipedia

http://en.wikipedia.org/wiki/.300_Remington_SA_Ultra_Mag

and they say the case is slightly smaller than a 300 WSM, which is 82 grains water. I would suspect then, that the 300 RSUM is a bit bigger than the 30/06, which with Lapua brass, is 68.6 grains water full to overflow. A 30/06 AI is about 72 grains water. I still can't find anyone saying how much water the 300 RSAU holds, and the first site I googled had a virus, so I stopped looking.

* * *

The 210 SMK is a clone of the 210 Berger, what would stabilize the one would stabilize the other.

If extreme accuracy is your goal, it is a bit optimistic to set up for only one bullet. Barrels are finicky, you have to go with what they like, not what you like. Still, if your rate of twist will stabilize a 210, you'll be good to go with the shorter bullets.

If the case is really closer to the '06 (~70 grains water) than the 300WSM (~80 grains water), you could likely use .30/06AI reloading data. German Salazar has done some recent testing with the plain-jane '06, you might read his blog.

http://riflemansjournal.blogspot.com/p/articles-index.html

Bear in mind that German has spent a lot of time testing primers, and has some beliefs strongly held. While I'm quite sure he is generally right, some recent testing of mine has lead me to the belief that individual barrel/bullet/powder combinations may show a preference for a hotter primer. In my opinion, you have to test, and for accuracy at this level of detail, it takes a 10-sot group -- with several 10-shot better. As a benchrest shooter, I'd say with some barrels/bullets/powders, magnum primers *agg* better, even if the general preference is for standard to lighter primers.

Hope this helps

 

[zini72]

according to my version of Quickload, the RSAUM has 74 grains of water capacity. You may want to double check your own brass.
Good Luck!