Re: which powder ? 7mm ultra mag w/ 32" barrel & 139gr sst interbonds.
As far as twist, I'd suggest 1-9 or 1-10 as you may eventually want to shoot heavier bullets (factory is 1-9.5).
My Sendero with factory barrel (26", 1-9.5, and so much freebore a 139 falls out of the case neck before it touches the lands) likes RE25 with the 139 Interbond. 3553 fps with 96 gr, 3.600 oal, no mark, easy bolt lift (slight mark, easy bolt lift at 97gr, 3623). That's only in MY rifle! I'd start no higher than 90gr and work up (I'm sure all that factory freebore is letting me load a couple extra grains of powder).
With the Interbond's .486 BC, you can't ask for anything much flatter to 400.
[ 01-29-2004: Message edited by: JGH ]