I have not had good luck with it in my 300WSM and 180-200 grain bullets. Accuracy is average at best. YMMV...

More importantly, it was sort of a pain to work with. The grains are VERY fine and really like to jump out of scale pans and tops of cartridges, and since almost every load is compressed, spillage is common. It is prone to static sticking too because of the small grains.

Velocity is first rate, and the larger powder charges show up in higher recoil too...have fun!

I'm using it in my 270WSM with 140g bullets and getting great results. In fact it Excels with the 140g and seems to work well with 150g bullets.

It gives me the best velocity for the 140g weight and accuracy is well under 1"

I tried it in my 300 WSM, 30-06 and 25-06 and didn't find any advantage over IMR 4831, IMR 4350 or RL-19 for those calibers.

Anyone using this slow burning ball powder in thier reloads?? I'm looking for personal data( I have the data from the AA site ), or real world experience with this powder in the 270 win or 300 weatherby. Any help much appreacted....41

My 300 wsm loves the stuff with 2940fps with 180 Hornady sp and it shoots an inch at 200 yards. I tried it in my 270 with 150 Hornady's and it shot about 3 inches at 100 yards, so the experiment ended right there.

41rem,
Magpro seems to have a real niche in the short magnums when it comes to the Velocity department (Particularly the 270WSM & 140gr bullets) and maybe only half of the rifles out there maintain any kind of consistant accuracy at the upper powder charges. I got upwards of 3400fps 270WSM & 140gr bullets, but groups went in the toilet.
As for using it in conventional long cases such as the 270Win, 25/06, and the shorter 243Win, it hasn't shown me anything I can't do with IMR4350, IMR4831, or R-22.

I use 70 grains of Magpro with a 140 Accubond in my .270 WSM. This gives me a velocity of 3150-3175 fps in my Savage 116BSS. I use Federal 210 primers and Winchester brass that has had the flash holes deburred. The accuracy with this load is a consistant .3-.6 MOA. As stated above, it's a great powder for 140 grain bullets in the .277 bore.I think it would be worth working with in your .270 Win. Here's a group that I shot today with Magpro.