300 RUM Load development*group pics added*

[Tikkamike]

I recently got a 300 RUM and have started load development on it. I am using 200 Barnes LRX and Retumbo with Federal 215's I first planned on starting around 90 Gr. but after consulting my Barnes manual they had a much lower starting charge... in the 70's which I found to be ridiculous.. even their max charge seemed low but reluctantly I started within their parameters and have now worked from 87 grains up to 92. I wasnt seeing much velocity increase till I got to about 89 grains, before that it was stuck at about 2950ish. and grouping seemed sub par. at 90.5 I started hitting the low 3100's and it has kind of plateaued but my groups are shrinking dramatically. I am monitoring pressure signs, the bolt lift is getting slightly stiffer but not bad I expect to find max pressure within a grain or so Then I will try it out for a while reloading the same few pieces of brass over and over to see what kind of life I can expect out of my brass. I may have to adjust it if it wears brass out too fast. I have a new box of Nosler brass sitting here and I hear its softer than other brass so I want to be sure I dont wear it out right away. I will keep you guys posted and maybe be able to come up with some useful load data for someone wanting to use 200 LRX with retumbo.

 

[lamiglas]

Re: 300 RUM Load development

Mike,

I just finished doing load development for a friend that has the same gun you just purchased. we are using different componets, but i just thought i would share one thing.

after messing around with oal, and powder increments for a couple of weeks, it was a very consisent .7 to .9 gun. i finally changed the torque in the action screws to 40 in/lb and the groups shrunk drastically. since then it has consistently shot groups in the .4 to .5.

this gun is free floatet ,but not bedded.

 

[Tikkamike]

Re: 300 RUM Load development

Thanks for the tip. I floated mine this weekend and plan to bed it after I have my load done and see what it does to group size.

 

[lamiglas]

Re: 300 RUM Load development

I will be anxious to know how it turns out. He is considering bedding his, but its shooting great now, so not sure he will. I am curious to see if his point of impact changes after he takes the stock of and puts it back on. i think this is where the bedding will help.

 

[Tikkamike]

Re: 300 RUM Load development

it will more than likely change unless he just gets lucky. I have only ever had one rifle that i could take out of the stock then replace it and not have to re zero my rifle

 

[lamiglas]

Re: 300 RUM Load development

I have had similar experiences. if it were mine I would bed it.

 

[Camshaft]

Re: 300 RUM Load development

I have pressure tested these3 in my 300rum and found the max to be around 92gr of Retumbo, which is giving me 3085fps with an ES of 19fps. I havn't put these on paper yet, but from the consistency i'm getting it should be fairly accurate. I had some loads at the range with me yesterday to try out, but by the time i finished messing with my 300wsm, my shoulder was done in.

 

[Tikkamike]

Re: 300 RUM Load development

what were your pressure indicators?

 

[Camshaft]

Re: 300 RUM Load development

Flattened primers and ejector marks. Bolt lift stayed smooth and easy but I always stop when I get ejector marks or flattened primers. If I get cratered primers I back it off.

 

[Footsore]

Re: 300 RUM Load development

I will be interested to see what you come up with. My new 300 RUM is on order and I am patiently looking on while waiting.
Hodgdon Data shows a range of 81 to 86gr of Retumbo for the 200gr Barnes XFB which is much less than the 89 to 95.5gr they recommend for the Nosler 200gr Accubond. Just goes to show that all projectiles of the same weight are not always interchangable.
Keep us posted

 

[meatyrem]

Re: 300 RUM Load development

Would anyone happen to have photos for a good example of cratered primers. I don't believe I have run across one yet.

 

[Tikkamike]

I finally decided that 91 gr of retumbo seems to be about max after looking at my cases and thinking about the results, not the velocity I wanted but I think in this case its just what I am going to get. which is about 3125 average. Anyway the first 4 shots on this target are the 4 middle ones and the outside 2 naturally are 5 and 6. My barrel never really got warm as I had a nice cool morning and lots of time to let it cool between shots. however there is a certain amount of heat retained each shot so the last 2 being on the outside of the group does not surprise me. This group is not very good although shows promise to me. Again the bullets are 200GR LRX seated .050 off the Lans. I am thinking I will try a group that is .010 further off the Lans and a group .010 closer. and see if the group wants to tighten up or open up or stay the same. I have a sneaking suspicion that one way or the other it is going to tighten up a little. And maybe this rifle is no good for 5-6 shot groups maybe I need to get my info from 3-4 shot groups but I will load 2 more batches of 5 and see what happens. Any and all input wanted.

 

[lamiglas]

I would be curious to see if changing yout torque setting makes any difference. If u happen to try it let me know.

 

[Tikkamike]

I would be curious to see if changing your torque setting makes any difference. If u happen to try it let me know.

i am sure it would but i dont like messing with torque on screws i just have a standard that I use on my 700's and dont want to have to play with it everytime i take the gun apart. so I plan to bed it once i get it as good as I can and hopefully it improves it.