My 7mm RM load for 140gr. Sierras is, CCI mag, RL19 at or a little over max. ( I THINK it was 73.5gr but I don't have my notes here at work)

Shoots quite well, and will definately make mush of a deers chest cavity!

H4831 will work Great in all of the Combos you listed.

I like R22 alittle better in 7mm & 300 Mags but, some say it is Temperature sensitive. Here, Temp deviation isn't that big of a deal so, I have never been able to see a difference.

Good Luck!

Reloader

.270:
RL-19 From 48.4 grains to 60.0 grains
Winchester WLR Primer

7MM:
RL-25 From 66.5 grains to 71.5 grains
CCI-200 Primer

.300:
WMR From 61.3 grains to 75.8 grains
Winchester WLR Primer

I don't recommend following anyone's loads that you get off of the internet. Get youself a couple of good reloading manuals (Nosler's especially), and take it from there.

Be prudent.........

AD