how is the accuracy, fps and terminal ballistics?

I've not used them but I'd venture that these bullets would act solids at 45-70 velocities.The fact that they were partitions would be meaningless.
Jim

Garrett Cartridges was going to market them in there 45-70 line up.At 2150 fps the .458 Nosler PP out penetrated the .375 H&H Mag with a 300 Nosler Partition.

The 300 Nosler out penetrated every bullet that Rick Jaimeson tested in the .450 Marlin by over 7 inches with the Barnes 300 XFN being the second place winner.

The Nosler out did the 350-Hornady/350 Speer/400 Speer and the 400 Swift A-Frame by several inches.


Jayco

that is impressive to say the least...do you think the grenade affect (the first quarter of the bullet spews out shrapnel) helps with penetration? that along with the smaller expansion.

I use Win Partition in my 1885.As accurate as any 300 factory [easy 1" groups @ 100 yds] Excellent performance on deer.I went to the Nosler because some of the 300s were too fragile at the close ranges here , usually 50 yd shots.They do expand and create a good but not excessive wound channel.Of course you don't recover the bullet !! Because of it's penetration some use it successfully on things like elk.

My Guide Gun "Mjolnir" really likes the 300 grain Partition Winchester factory load, shooting them into 1-1/2 inches and better at 100 yards. I'll let you know how they work on whitetail next month. Good hunting!

I've seen picture of Buffalo being shot with this round. It penetrates completely. A friend shot a moose with one and the same results. It is a very well constructed bullet and the ones I've shot were very accurate.

Yesterday I watched a tv program where a bison was shot [more than once] with the Federal 300 Speer HP. I would not use this bullet on bison ,the Partition would be much better !!