300 RUM Reloading Help

underdog

Member
Joined
Jul 1, 2009
Messages
18
Ok, need some advise on reloading the 300 RUM. Attached are some groups that I shot today, all groups were shot at 200 yards. Both of these loads are MAX listed in the Sierra load manual and supposed to produce somewhere in the neighborhood of 3100 FPS. The RL-25 is at 2953 FPS and the H-1000 is at 2970. Neither load showed any signs of pressure. Today was a cold day at 10 Degrees F but I cant see the temp having a 100+ FPS effect on the velocity. I am utilizing a RCBS chronograph to capture velocity.

Any information that could be provided would be greatly appreciated.

Rifle
REM 700 LR
26 Inch 1:10 Twist

Load Data
91.3 Grains of RL-25
Bullet=200 Grain Sierra Game King
Brass=Norma
Primer=Win Mag
OAL=3.595
Average Velocity=2953
ES=20

IMG_0362.jpg

Load Data
91.5 Grains of H-1000
Bullet=200 Grain Sierra Game King
Brass=Norma
Primer=Win Mag
OAL=3.595
Average Velocity=2970
ES=40

IMG_0363.jpg
 

brentc

Well-Known Member
Joined
Apr 3, 2009
Messages
2,525
Keep working with H1000 or find some Retumbo. Look up how to do a ladder test and run it. This should get you a good full power load in your RUM.
 

underdog

Member
Joined
Jul 1, 2009
Messages
18
Can someone with quick loads look and tell me if the velocities are consistent with the load data that I posted?
 

Jokostel

Well-Known Member
Joined
Dec 1, 2011
Messages
359
Location
Bismarck,ND
Keep working with H1000 or find some Retumbo. Look up how to do a ladder test and run it. This should get you a good full power load in your RUM.

Exactly.
NEVER believe books. They are NOT gospel. They are a guideline.
Run the tests, as every rifle is a law unto itself.
I've had 300 Wins that would make people do a double take.... 3250 on 180s and 3150 on 200s.... and get **** good brass life... 7+ shots before they got loose...

Plus... you don't handload going to the "Max".That's flat out dangerous.
If you loadshop..... please please please..... buy factory ammunition.
 

mountaincarver

Well-Known Member
Joined
Jan 24, 2015
Messages
162
Location
colorado
hello, just read your post. not sure if your concerned about velocity, or the groups. I have just spent the winter with my 300 rum load testing and getting a feel of how it performs with different bullets and powders. ive shot about 250 to 300 rounds through it. as far as velocity, I noticed mine started shooting faster after about 75 rounds or so. about 100 ft per second. looking at your groups, they look very familiar. I would bet that the gun will do better. what I did was picked a seating depth relatively close, then load tested in .5 grain increments. I never shot closer than 200 yards. be very careful with parallax. I watched my groups change from horizontal to vertical and so forth. then magic happened and one or two of the powder charges produced nice tight groups (1.125" at 200). Be sure to chrony all your loads. I found that some of my best groups had a terrible spread in velocity. I could get the spread closer by adjusting powder, but the groups would open up then. I fixed this by starting over with different powder. ive got 3 bullets to shoot very well, and all three came together with slower velocity than what I was hoping for. not a big deal to me. my gun just so happens to shoot very fast compared to others, so im about 4 grains lower in powder than others. I have a buddy who finds his accuracy shooting way more powder than I do, and about the same speed. I hope this helps as you work with your gun. h1000 has been pretty darn good stuff in my gun.
 

reelamin

Well-Known Member
Joined
Feb 13, 2012
Messages
124
Location
West
Working with my RUM again, so I'm back on here. I would say you were in the velocity range, but every rifle is different. Bottom line is you are chronographing your rifle with your pressure, so it does not matter what everyone else gets in their rifle.

I load for a couple 300 RUM, and they both love Retumbo for 165-190gr bullets. Mine loves 50BMG for 200-210gr bullets. R25 works pretty good also, but H1000 not so well.

Based on your groups I would be more concerned with the loads overall accuracy and stringing more then velocity. Checking your bedding/bolt tension. I personally do all load development at 100yds, and then check and verify stabilization later at 300.
 

underdog

Member
Joined
Jul 1, 2009
Messages
18
Exactly.
NEVER believe books. They are NOT gospel. They are a guideline.
Run the tests, as every rifle is a law unto itself.
I've had 300 Wins that would make people do a double take.... 3250 on 180s and 3150 on 200s.... and get **** good brass life... 7+ shots before they got loose...

Plus... you don't handload going to the "Max".That's flat out dangerous.
If you loadshop..... please please please..... buy factory ammunition.

Rest very assured that I have been hand loading various calibers for 20+ years. Didnt just run out and buy a chony for giggles. With that said I am not naive enough not to think that I can still learn something. I worked up to these loads after starting low as any hand loader should do.

I will pass on your offer to buy factory ammo and continue to receive the good information form the members of this forum.
 

underdog

Member
Joined
Jul 1, 2009
Messages
18
hello, just read your post. not sure if your concerned about velocity, or the groups. I have just spent the winter with my 300 rum load testing and getting a feel of how it performs with different bullets and powders. ive shot about 250 to 300 rounds through it. as far as velocity, I noticed mine started shooting faster after about 75 rounds or so. about 100 ft per second. looking at your groups, they look very familiar. I would bet that the gun will do better. what I did was picked a seating depth relatively close, then load tested in .5 grain increments. I never shot closer than 200 yards. be very careful with parallax. I watched my groups change from horizontal to vertical and so forth. then magic happened and one or two of the powder charges produced nice tight groups (1.125" at 200). Be sure to chrony all your loads. I found that some of my best groups had a terrible spread in velocity. I could get the spread closer by adjusting powder, but the groups would open up then. I fixed this by starting over with different powder. ive got 3 bullets to shoot very well, and all three came together with slower velocity than what I was hoping for. not a big deal to me. my gun just so happens to shoot very fast compared to others, so im about 4 grains lower in powder than others. I have a buddy who finds his accuracy shooting way more powder than I do, and about the same speed. I hope this helps as you work with your gun. h1000 has been pretty darn good stuff in my gun.

mountaincarver - Thank you for the information. I am a perfectionist so I am worried with both velocity and accuracy :) In all seriousness though I have put ~50 rounds out of this gun and it does seem to be coming into its own with a little bit on barrel seasoning. RL-25 seems to be a little more consistent than H-1000 does and the group is not that bad for 200 yards. I just need to get those fliers out of the mix. I am going to try bumping it up from 91.3 to 91.5 and 92 and see where that gets me. Plus I am going to hold our for a reasonable day to shoot. Say in the 30's, which mimics my usual hunting temps.
 

underdog

Member
Joined
Jul 1, 2009
Messages
18
Working with my RUM again, so I'm back on here. I would say you were in the velocity range, but every rifle is different. Bottom line is you are chronographing your rifle with your pressure, so it does not matter what everyone else gets in their rifle.

I load for a couple 300 RUM, and they both love Retumbo for 165-190gr bullets. Mine loves 50BMG for 200-210gr bullets. R25 works pretty good also, but H1000 not so well.

Based on your groups I would be more concerned with the loads overall accuracy and stringing more then velocity. Checking your bedding/bolt tension. I personally do all load development at 100yds, and then check and verify stabilization later at 300.

Thanks reelamin. I have been pondering 50BMG or US869 but I currently have:
H-1000
Retumbo
Reloader 25
IMR7828

All are supposed to be good for this cambering. Some better than others dependent on bullet weight.
 

BEEMAN

Well-Known Member
Joined
Oct 20, 2011
Messages
1,685
My Sendero loves 91 gr of H1000 with a GM 215M primer. I would suggest you try the 215 or 230 Berger hybrid. The 215 shoots so good in everything. Very forgiving bullet. Start it at around 30 thou off and you will be good. This is a fairly mild load in my gun. No pressure at all, and runs them at 2985 fps.
 

barefooter56

Well-Known Member
Joined
Nov 10, 2014
Messages
913
underdog,
Are the target pictures you posted sideways from the position you shot them at? In short are we looking at horizontal or vertical stringing here?
 

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