Two questions.... first
I bought a keg off a guy a while ago at a killer price, and finally got around to starting work on some new loads with it... I was kind of surprised to see the seal was missing when I opened it, and also.. that it was ball powder. (I'm an IMR guy... used to those cylindrical slow powders..) So.. first question, 8700 is ball powder??? (I knew this guy for years, have no reason to believe he would sell me something that was mixed or swapped... but just want to make sure. Don't want to find out the hard way that I loaded a 300 UM with fast burning power and end up missing my face when I go to try it out!) Second question... being a discontinued powder, I can't seem to find any recipe for my 300 Ultra mag anywhere.. even though I must have a half dozen of Accurate's manuals... they are all too old for the cartridge, and their web site don't list any loads since it was discontinued. So... any input would be appreciated.

Yes, AA8700 is a ball powder and is very close in burning speed and characteristics to H870 (now, I wonder why the similarity in names?) H870 itself has been off of the market for a number of years, so you may not be able to find any data for it for the .300 RUM.

AA8700 typically falls in between H1000 or RL-25 on the faster side and U.S. 869 on the slower side. These very slow powders are fairly gentle when working up a load from below, so if you have a chronograph and some known velocities from your gun, if you feel competent to do so you can likely work up some useful loads with it for your rifle -- but proceed at your own risk and with full knowledge that YOU are the only one in control and bear full responsibility for your actions.

Thanks Stone Creek. I found some data for the 300 Winchester mag and it lists loads of 86 grains.. so I'm sure a 90 Gr start load for an Ultra should be well below max. I just feel better now knowing for sure it is what it is....

the gundawg. sorry so late on this post, was out of town.
From the accurate guide 2004.

180gr. bullets start load 101.7 to max load 113.

200 gr. start 94.5 to max 106 to 111 depending on bullet.

PM me if you need more info.

Modern Reloading second edition, Richard Lee gives you all the data your heart could desire. roger