300 ultra mag reloading info

Getting ready to load for my 300 ultra. I drew a Utah early rifle Elk tag and would like to develop a load for my rifle and this hunt. I have only used factory ammo with this gun with good results, but the ammo I used is no longer available. I Have reloaded for smaller calibers.

Looking for a starting point

I have the following components

Rifle: Remington std 700 SSL 26 inch

Remington brass

Powder: H1000 (starting weight) do I ± my powder weight by .5g 88.0, 88.5, 89.0, 89.5, ............300 has lots of powder.

Bullet: Hornady ELD X 200 gr. does the ELDX have a sweet spot ( seating depth ) I have heard the ELDX is pretty forgiving. I am limited to C.O.A.L. by my STD mag.

I know every gun is different to reload for, but I'm looking for a starting point from somebody that has more experience me.

Thanks

I ran the 300 RUM at factory length for the first 2 years I shot it after its introduction reloaded with H-1000. The ELDX wasn't around then but I think it was the Accubond which is similar.

H-1000 - start somewhere around 87.0 grains

Retumbo - start somewhere around 89.0 grains (my favorite...)

These numbers coincide with the data on the Hodgdon website also for starting loads.

OAL is magazine length at 3.600" which works quite well.

There are other powders so if you get tired of these more can be supplied.

It's pretty easy to get a 4" wyatt box installed. Get a Smith with a mill and order one dont let mag box length hinder you with the bullet you want to shoot or were the rifle wants to shoot the best.
A 215 Berger and proper freebore are bad medicine on elk as long as you have a 10 twist.

I ran my 220 ELDX at mag length. I was running RL26 It shot very well but the pressure changed once the temps got up later in the year so I was using some of the first published data that hornady put out but in there 10th addition book RL26 is backed off a little from there original data. Anyways, I took my deer that year at 761 yards. So yes I think they are pretty forgiving.

I had great luck with Retumbo, what little I messed with my RUM.

My personal is 88 gr. With a eld-x. Norma brass at 3.660.
Very accurate in a three land Lilja. Never run eld-x on a bull, 210 vld's have been my go too. 30 inch tube I get 3k even with single digits for sd. Good luck and work up.

I settled for 90-93 Retumbo with 200 Nosler accubonds. The load came from MTMuley 3 years ago. Mag length.

In my custom Rem 700 I run 91.0gr Retumbo with a Berger hunting VLD 210gr. Groups @ 500 are inch or better....plus, with custom turret on Zeiss Conquest scope, I dial between 200-600 and in between and all hits are where you aim. Muzzle velocity is 3050fps...if it helps...rsbhunter

The heavys are great goal if you need to go there but with most 26" Rums H1000 or Retumbo @ mag length + 200 grain Accubonds or other 200s are so forgiving loading and shooting out 500 = easy start.

Start lower than 88.0. Never know what YOUR rifle will do. I have had some that pressured out with a tight bore at 87.0 H1000. I would start a ladder rest at 85.5gr myself.

I have a .300RUM that likes H1000 under the 215 @ 3105fps, and Retumbo under a 230 @ 3113fps. The 230 is a max.load in my 28" barrel rifle. The 215 is close, but not quite max.

Powder wise I've had best luck with Retumbo but just started trying N570, RL26 and RL33. Ive used 180 Barnes TTSX, Berger 185 AND 210 VLD on elk. TTSX are bone busters for sure.
Trying 181 Hammers this year. I'M sure they will out perform Barnes.
H1000 has been really good with 181 Hammers also.

Nosler brass fed 215 match primer 92.5 grs of retumbo and a 175 lrx 3122 FPS es 7 and sd 4 under 1/2" at 100 yds

Christensen 7mag said:

Nosler brass fed 215 match primer 92.5 grs of retumbo and a 175 lrx 3122 FPS es 7 and sd 4 under 1/2" at 100 yds

Click to expand...

Is this from a 300 rum?

Christensen 7mag said:

Nosler brass fed 215 match primer 92.5 grs of retumbo and a 175 lrx 3122 FPS es 7 and sd 4 under 1/2" at 100 yds

Click to expand...

I'm running these in a 300 wm at 3150 with a 24" tube.

I think you may be leaving quite a bit on the table in your RUM if that is what you are getting.

In my RUM early load development:
210 Berger .010" out
ADG brass
CCI 250
H1000
85 gr 3006 FPS
86 gr 3007
87 gr 3038
88 gr 3072
89 gr 3075

My first RUM so being a little cautious. I am not liking the look of the brass. So going to work around the 85gr mark and see how it does. Is ADG brass soft like Norma? I get swipe when I chamber and extract without firing.