My Brother-in-law has a 300 RUM that he may want to use on a Grizzly hunt. What bullet would best? I'm leaning towards a Swift. I he no experience with the 300 RUM. My biggest 30 caliber is a 300 Win Mag.

Accubonds or partitions.

In the end, there isn't a huge difference between any of the premium bullets. Just stay away from the target/match stuff.

200 gr. Partition.

+2

A friend of mine used one of these baby howitzers on elk for a few years. I'd definitely go Partition all the way.

The Swift AFrame is an excellent bullet. If your rifle likes it, then by all means use it.

168TTSX @ 3400 has never bounced off, but as has been mentioned any premium that it shoots well will suffice

Out of a RUM.....TTSX

I used a .300 RUM on a coastal grizzly last September. I mainly had it along for a possible goat add-on, but being that it was stainless and my .375 wasn't I ended up switching to the RUM to deal with near continuous rain. 180 Accubonds; I dare anyone to find a more instantaneously or thoroughly dead bear. Crushed it like a coyote.

On the grand scheme of things grizzlies aren't very big.

North Fork...

The 300 RUM does have some impressive ballistics.

BH63

I wonder a bit about that. My RUM does 3300 with 180s and my 300 Wins do 3150 fps just as regular as clockwork.(26" barrels)

That's a lot of buck and roar for a stinking 150 fps gain. It doesn't matter much now; the barrel melted out like a dropped ice-cream cone on a hot day. 600 odd rounds and it was hurt real bad.