What a good load for a 300 RUM?
I just got a new one and need to start some where.I would like to use a 165gr-185gr bullet.
Any help is helpful.

100gr +/- of Retumbo does well behind a 180gr Accubond. 3350fps +/-

Retumbo is your friend! And you will need a lot of it!

Thanks for the help. I have also seen RL22 and RL25 are these as good?

They're good but they are temperature sensitive. That's not an issue if you're shooting short range but becomes a PITA when you stretch it out.

This is what I'm doing but in 200 grain AB and going to start around 90gr. New to reloading but this seems to be a good set up from my readings on Long Range Hunting.com.

I vote for RL25 and 165gr accubond

retumbo and h1000

ouch!

lol, my Thoroughbred Rifle in .300RUM shoots the Hornady 225gr at 3170fps. I just use it to shoot off my one-mile tower. Everyone laying next to me is acutely aware of each shot when I torch it off It out runs a .338LM to one mile and is good to 2000 yards + given the density altitude. Now that's ouch.

And when your standing next to it watching someone else shoot it you can see the barrel shutter with each shot. Glad I dry fired it first, learned it has a 12 ounce trigger.

ive got a load for a 125gr nosler bt that is shooting right 4000fps!!! its a beast!!!!

Whats your load? Sounds a little fast.

I use 180 gr with different makers with RL22. Trying to recall it but it is around 88 or 89 gr +/- of 22. I like the load and it does well. I tried ballistic tips and they were fast but not stable and now I stick with barnes, swift, and nosler bullets. Killer on deer and hogs.

H1000 and 165 Accubonds work well.

might have over exaggerated the speed. only 3950 fps

not a max load, but getting close, probably could bump it up a tiny bit but not much. recoil is insane even with a muzzle break. muzzle blast is huge!! its a sub moa load. i use this load for 1000 yards too. Shot a coyote at 30 yards and it disemboweled him. works good on deer too if you want to pre tenderize it.

125gr nosler BTBT
RP Brass
RL 22 98gr
3950 fps
calc says 4329 ft-lbs of energy at muzzle

Question.

I am trying to figure out my OAL, manuals say 3.600. I am shooting some rounds that a friend loaded for me 150 grain nosler and they measured out to 3.630.

With the 200 grain Accubond and 90gr of Retumbo should I stick to the 3.600? I am shooting a Sendero .300 ultra mag.

RL22 with 165 gr VMax 96.7g

The 3.600 is the SAAMI specs on the round. The 338 Ultra uses the same OAL however I am using 4.020 length rounds. This has to do with the length of the throat in your chamber, and the manageable length for use in your magazine. I am unable to use the box mag in my rifle. You can possibly get away with longer than 3.600 but the longer you get the more likely you are to have a hang up when the bolt is stripping a round from the mag.
Also note that as you creep out longer, you may engage the rifling on a round that wasn't worked up as such. The increase in case volume by extending the bullet further out of the case will not decrease the pressure enough to overcome the huge increase in pressure from the bullet being jammed into the rifling. IT may go boom boom.


As for "guns ups" claim on 4K FPS out of the 300 ultra 125, he's not BS'ing. I have personally shot his gun through a chronograph. And if that's not enough, I helped clean a whitetail shot with it and it was a damn mess.

Ok so heres a little bit different question how do these loads group? Say at 3 to 500 yards

168 berger 88 grns 22

As for "guns up" the 125 is not the best for long range hunting but will work none the less. I've watched him shoot a 12" gong, over and over, shot after shot at 1000 yards with it.
That will kill any whitetail.

As for powder choices, I am seeing some use of the 50 BMG powders in these big powder burners. Used under heavier bullets of course.

shot a coyote at 30 yrds with the 125 out of the 300 ultra never went through exploded on impact took out the whole side it would be a bad choice for larger game up close futher out would probaly be ok

I used to have a .300 RUM and remember it being most accurate with Retumbo as well

180 Barnes under 96 gr retumbo 3.60 coal out of a sendero with a brake running 3290 not presher signs , PLEASE ALWAYS WORK UP LOAD NEVER USE OTHERS LOADs over max