300 RUM Load development Qs

[jonnybullslayer]

I've searched quite a bit for pet loads on the 300 RUM with 215 grain bergers before I built some rounds and headed out to the range. I decided to start at 88 grains of H1000 and increased by 1 grain increments up to 94 grains, loaded .015 off the lands. I had intended to run 3 separate ladder tests at 400 yards, but I was shooting under the tutelage of a long time shooter and he suggested we shoot groups at 100 yards.

I fully expected to see pressure signs before hitting 94 grains but I didn't. Is this normal?

My best vertical spread for a three shot group at 100 yards came at 94 grains (3134 fps ave) with an ES of 18 fps and although 93 grains (3111 fps ave) gave a slightly larger group, ES was 10 fps.

88 grains (2996 fps ave) had two shots touching and one flyer, but ES was 9 fps.

Where should I focus my fine tuning? I'm not seeing anyone sharing many loads in the mid-90's, but again I'm seeing very little pressure signs. I was going to try 5 rounds each of 93.5, 94, and 94.5. Or should I be looking at 87.5, 88, 88.5?

I'm a little hesitant to move forward.

 

[RockyMtnMT]

I've searched quite a bit for pet loads on the 300 RUM with 215 grain bergers before I built some rounds and headed out to the range. I decided to start at 88 grains of H1000 and increased by 1 grain increments up to 94 grains, loaded .015 off the lands. I had intended to run 3 separate ladder tests at 400 yards, but I was shooting under the tutelage of a long time shooter and he suggested we shoot groups at 100 yards.

I fully expected to see pressure signs before hitting 94 grains but I didn't. Is this normal?

My best vertical spread for a three shot group at 100 yards came at 94 grains (3134 fps ave) with an ES of 18 fps and although 93 grains (3111 fps ave) gave a slightly larger group, ES was 10 fps.

88 grains (2996 fps ave) had two shots touching and one flyer, but ES was 9 fps.

Where should I focus my fine tuning? I'm not seeing anyone sharing many loads in the mid-90's, but again I'm seeing very little pressure signs. I was going to try 5 rounds each of 93.5, 94, and 94.5. Or should I be looking at 87.5, 88, 88.5?

I'm a little hesitant to move forward.

I am not sure what your expectation is, but I do not find much worth in .5g increments in a case of this size. If it were me I would take the higher vel load and shoot it for group at longer range. If the group size is not quite good enough then adjust seating depth and see if it helps. I will generally figure that sub moa is good. I find 100 yard targets generally worthless other than shooting for vel or setting a zero. ES in the teens on a large magnum is very good. So unless you really like tinkering with the load I would zero it and go practice with it.

Steve

 

[jonnybullslayer]

Thanks Steve. This is my first foray into the long range game and I REALLY wanted to do the ladder test at 400 yards as I've read that shooting too close can give inconclusive results. But I was having trouble with my chrono, so I went to the range with a veteran shooter friend who insisted we shoot at 100. We were using his chrony and he will be helping me with my shooting out to longer ranges, so I didn't argue.

We are supposed to zero today then shoot out to 550. Next weekend we will shoot 800 to true our velocities, then shoot for 1000. I guess I'll just load up some 94 grain rounds and see what happens.

Logic would say that the best group at 100 would be the one to go with, but I've heard that these bullets don't "settle down" until further out. In your experience, have the loads producing better groups at 100 been the same ones producing better groups at further distances?

Jonathan

 

[RockyMtnMT]

Thanks Steve. This is my first foray into the long range game and I REALLY wanted to do the ladder test at 400 yards as I've read that shooting too close can give inconclusive results. But was having trouble with my chrono, so I went to the range with a veteran shooter friend who insisted we shoot at 100. We were using his chrony and he will be helping me with my shooting out to longer ranged, so I didn't argue.

We are supposed to zero today then shoot out to 550. Next weekend we will shoot 800 to true our velocities, then shoot for 1000. I guess I'll just load up some 94 grain rounds and see what happens.

Logic would say that the best group at 100 would be the one to go with, but I've heard that these bullets don't "settle down" until further out. In your experience, have the loads producing better groups at 100 been the same ones producing better groups at further distances?

Jonathan

Generally yes the better group should be better farther out. What I have found is a load at 100 that does not look good may not be bad after all. The group in inches does not get better farther out but the moa size of the group can get better. So a 1.5" at 100 could be 1.5 still at 300. Now all of a sudden it is a half moa load instead of a 1.5 moa load. As a hunter I always look for moa of deer out of my stuff.

Have fun.

Steve

 

[mtmuley]

While I generally agree small increments in powder charge are a waste of time in a big cased magnum, sometimes it may help. I re-stocked my .300 RUM, and afterwards my pet load that was a reliable 1/2 MOA or less perfomer opened up a bit. On a whim I shot some loads I had worked up years before that were half grain heavier than what I normally loaded. The rifle returned to the way it grouped before re-stocking. Not saying it is worth it in load developement, but sometimes a small powder tweak can help. mtmuley

 

[jonnybullslayer]

While I generally agree small increments in powder charge are a waste of time in a big cased magnum, sometimes it may help. I re-stocked my .300 RUM, and afterwards my pet load that was a reliable 1/2 MOA or less perfomer opened up a bit. On a whim I shot some loads I had worked up years before that were half grain heavier than what I normally loaded. The rifle returned to the way it grouped before re-stocking. Not saying it is worth it in load developement, but sometimes a small powder tweak can help. mtmuley

Good point. I went ahead and reloaded all 94s for today's shooting. If I don't like it, I'll try 1/2 grain intervals next week.

 

[jonnybullslayer]

Went to the range today with my 94 grainers. Shot reasonably well at 100 (1 MOAish) then I went to the table and found my drop for 550. It called for 7 MOA based on my velocity, but ended up being 8. Once dialed in, I made 3 consecutive hits on the 4" heart of the steel target. I'm happy with that! I will reload one more time, then anneal. Again, I'm not seeing much for pressure signs, but I want to make sure I don't start splitting necks. Trying for 800 and 1000 next week. First attempt ever, so I'm pretty excited.

 

[RockyMtnMT]

Went to the range today with my 94 grainers. Shot reasonably well at 100 (1 MOAish) then I went to the table and found my drop for 550. It called for 7 MOA based on my velocity, but ended up being 8. Once dialed in, I made 3 consecutive hits on the 4" heart of the steel target. I'm happy with that! I will reload one more time, then anneal. Again, I'm not seeing much for pressure signs, but I want to make sure I don't start splitting necks. Trying for 800 and 1000 next week. First attempt ever, so I'm pretty excited.

Nice job! Well within moa of deer. Dead deer at 550 no problem. Load is looking good so far. Shot moa at 100 and sub moa at 550. Can't rely on the 100 yard butt for accuracy.

Steve