THere are alot of GOOD powders that will work in the 7mm RUM.
For conventional weight bullets, Retumbo is about as good as it gets and very consistant over temp changes and pretty good with elevation changes as well.
If your using the heavier bullets, the slow burning ball powders also work very well such as AA8700, old H870, H-US869 and the surplus powders such as WC872 also work great. You will get very good velocity, great load densities and generally very consistant velocities with these powders. Sounds like win-win but not always.
These powders will add 5 to 10 gr to the powder charges you will be using compared to stick powders. SO what? well, this increase recoil, not an issue if your using a brake but if not you can feel the difference in recoil, especially in a sporter weight rifle.
Also, these powders do not burn very clean, in fact they are quite dirty burning. Even if you can get enough powder in the case to get up to around 65,000 psi, they still leave MUCH more carbon fouling in the bore compared to modern stick powders.
Also, if you will be shooting and hunting in varying elevations of in varying temperatures, you will see a much more significant change in POI with ball powders compared to stick powders.
Do not read this as me being down on these ball powders, I am certainly not in any way but you need to realize their characteristics to get the best use out of them. I use them alot in my larger capacity wildcats and they work great. You need to remove the carbon fouling every 25-30 shots down the barrel and if you want to load to full pressure, you will need a cool and hot temp load for summer and winter. I generally just load to a safe load in hot temps and then when its cold, test the rifle to see what velocity its getting and develope my drops off that so I do not have to play with different loads, 100 fps change does not make any difference as long as you have your drops corrected for the velocity drop.
If it were me, I would probably start with Retumbo and see how it performed for you, if that did not work up to your performance specs I there are other options but those other options come with other issues.
Allen Precision Shooting
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