Welcome to BGH

180 grain bulets for both calibres. The barnes bullets are excelent choices.

Enjoy the hunt

i used the 180 accubonds in winchester supreme in my 300wsm. punched a dandy hole in our moose last fall

E. Johnson, Welcome to BGH! Either weapon will work well for Wapiti. I use a .300 Win Mag. for all of my big game hunting and really like it. One thing you should make sure you have is good ammo...that will hold together and perform well on larger, big boned animals.

I used a 300 WSM 180 gr Fail Safe on a 59 inch Alaska moose in 2002 and it only took one shot to bring him down.

I've used them ever since for Elk.

L-Ray

I shoot a 270 WSM, A 300 WSM and still have several 30-06 around the house.

In the older Cup and lead core bullets, I always used the 180grain bullets/

Barnes has often said you can one or two weights lighter with their Copper bullets. So I worked up load with a 168g TSX over IMR 4831. for my 300 WSM and the 30-06. It has worked great on Elk.

I've also shot several spike bulls and cow elk with my 270 WSM using the 140g TSX bullets in my 270WSM. They have always given me complete penetration. One spike bull the 140g TSX entered by the base of the neck, hitting a neck vertabrae, passed through a lung, Hit and broke a rib and followed the rib cage back exiting the elk by the tail bone. Complete end to end penetration.

Both calibers will work just fine. IMO, the most important thing is that you need to practice quite a bit between now and then and become proficient with whichever caliber you choose. You may already be there, I don't know you, but so many people I see have the newest, best new rifle and the problem is just that. The rifle is brand new with only a few shots through it and the person has no idea really how the rifle performs.
Bottom line, choose one, either one and practice, practice, practice. A well placed shot from either one will have the desired result.

Like others have said a 180 gr bullet out of a 30 caliber rifle is perfect for punching holes in your elk tag.

As far as bullet type I would stick with premium bullets like a barnes x, partition, accubond, trophy bonded bear claw among others. The trick will be finding the one that groups well out of your rifle. My old 30-06 loved partitions. My buddies rifle loved bear claws. But if we switched ammo we couldn't get either rifle to group well and that limits your range and takes away from your confidence. It might take some time and money to try different loads but when you get an elk in your sights there is no feeling like knowing you know where that bullet is going to go.