After looking at some reviews and answers, what about Barnes VOR-TX Ammunition 140 Grain TTSX Polymer Tipped Spitzer Boat Tail for elk? Does it have a enough knock down power? Thanks again!
I will hopefully know more in a few weeks. I'm taking a 300 WBy with 180 Barnes on an elk hunt. From what I am reading it sounds like Barnes should do very well as long as I do my job. We shall see!
Look at it this way - what was the "standard" 270 bullet that been used successfully on elk for almost 100 years? 130-140 grains. And that is an old-school lead or cup-and-core which is going to fragment and shed weight.
You push 140gr of mono that stays together at the same velocity you should be completely fine, just keep your impact velocity up around 1800 fps for a TTSX, 1600 for LRX (IIRC) for expansion.
300Wby @180gr is definitely enough for elk, same impact velocity constraints as above, just with perhaps a longer range and more room for error on a marginal shot (due to more momentum from mass.)
Just remember: 1/2mv^2 is great and all with exponential velocity, but the instant it contacts something and starts slowing down as it pushes through it's also bleeding off your KE exponentially. That's where the "bigger but slower" comes into play a little on the marginals/mis-hits, and the larger meplat (.308 vs .284 vs .264, etc) has a little more impact-transfer/hydraulics.
But honestly, boiler-room, hit where you're aiming, and just about anything will penetrate perfectly fine, especially anything mono.
I've run TTSX 130s in my '06 (1:9.5) quite well, never could get 150s to group but I have an idea why, and will be using 168s in either the '06 or the new 300PRC (1:8) if I can get it running and a load worked up for it before I leave for the hunt. Also have 175 LRX and 208 LRX, again, if I have time. The 130s are flat-base and don't have the BC I'm looking for this time around. The 168s in a 300prc will be screaming if I can find the right powder, and the 1:8 twist will allow me to run the super-long-for-weight heavier monos out of it, as I'm in California and we're a non-lead-non-free state. I might try the 198 Hammer Hunters at some point, we'll have to see.
Honestly, I'm a fan of copper over lead for a number of reasons, and the little bit of density you lose is -more- than offset by the advantages. I think you will be happy running quality monos.
Cheers, and g'luck out there...
-mox