300 RSAUM Loads

[hifidelity]

I am starting load development on my pet project Model 7 LSS Thumbhole 300 RSAUM. Powders tested will be H4350, H4831SC, IMR4350, and N-550,using 150, 168, and 190gr matchkings. Brass is std remington stuff all weighed and seperated by weight. Same OAL. Primers to be tested thus far on the list are CCI 250 Lg rifle Mag, and Federal Gold Match 210M. Anyone care to add any other primers to this lst, or known good powders for this caliber?

 

[hifidelity]

anyone?

 

[kmassaro]

www.shortmags.org

 

[shilen30]

What K2 says. Lots of 300 SAUM lovers on shortmags.com that would be more than happy to help you out.

 

[johnny k.]

Hifi,
I tried 165gr Ballistic Tips for a buddies Browning A-bolt in 300WSM and settled on 69grs RL22 and Rem 9.5M primers. 3-shot group was sub .5" @ 100yds. Never tried any other weight or style of bullet. Hope this helps.

 

[QuietHunter]

Hifi,
Sounds like you are on the right track.

Another good powder to try is Varget. While it is considered to be a bit fast for 300 SAUM, I have had excellent results using 55 grains to push 168 grain bullets.

 

[hifidelity]

I found a sweet one today....

190gr MK seated to 2.822 OAL sitting on top of 63.1g of IMR4831 with a Fed210M.

Yielded .3" at 100yds. This little gun packs a hell of a whallop though. I might look at a small brake. I shot some 150 NBT's near max and they were pretty easy on me compared to the 190MK's, but were around .5". I hunt with electronic muffs, so the brake isn't an issue for sound to me. I might go with the Ops Inc brake, seeing as how I put one on my full blown Sendero 300RUM. It tamed it wonderfully and I couldn't tell a difference as far as sound goes

 

[QuietHunter]

Hifi,
Did you chrono the 190SMK load?

 

[hifidelity]

No, I sure didn't. I plan on it when I get used to this new gamma master chrony.

 

[QuietHunter]

Please post your results. It is likely the next bullet I will work with.

 

[hifidelity]

I can tell you, the 190 MK's in my Model7 like to be just barely off the lands. 2.825 is just starting to touch the lands in mine. 2.822 is what it seems to like. I tried 2.820- touching at 2.825 and it liked 2.822 best. It's a fun experiment to me. I will see if I can find another load it likes this much. N560 is up next

 

[bullshooter]

is your model 7 thumbhole rifle a factory rifle? what is the barrel length?

 

[Reloader]

"This thing packs a walup"

You got that right! These short mags kick hard for their size.

My 300 WSM kicks harder than any magnum rifles I have ever owned. Fast powders+Light rifles+heavy bullets=One Hell of a Kick!

Good Luck

Reloader

 

[QuietHunter]

"Fast powders+Light rifles+heavy bullets=One Hell of a Kick!"
+ muzzlebrake = less much less recoil