too_many_hobbies
Go to this the following website and check out the subsonic data listed for Accurate Arms Powders.
http://www.accuratepowder.com/data/P...0page%2076.pdf
There are two other sources of reloading data. The most recent volumes of the Sierra and Hornady reloading manuals. I gave both Sierra and Hornaday a call and they send me the relative pages of their porspective reloading manuals.
Here are the loads that I have developed. I have shot all of the loads listed under "Not yet verified user loads" except load numbers 3299, 2973 and 2974. SPMORGAN on this site has developed loads 2973 and 2974.
http://reloadersnest.com/frontpage.asp?CaliberID=135
Another good source 300-221 fireball a.k.a 300 whisper (r) loads can be found in the reloading manuals under the 357 magnum, expeciallly the loads listed for the TC or rifles. The powder capacity for the 357 magnum is very similar to the 300-221 fireball except that the 300-221 fireball can run at significantly higher pressures 52000 verus 45000 cup, respectively. But I would only stick to powders with similar burn rates as W296, H110, IMR4227, H4227, RE7, AA#9, 2400, V110, and AA1680 (sorry if I left someone favorite powder out... if so jump in here.... thank you)
Good luck and have fun
320pf