Read my 284 Hunting Rifle Post right below this post. Using A quality bullet...Barnes..... and A good lung hit,total pass thru.My loads at 2850 and there not going anywhere and these are ELK. I may be selling my 6.5 Grendel Cooper bolt gun, An honest safe 200 yd deer gun...with Barnes bullets.
Your correct the barnes ttsx/tsx are excellent for the use described, its a safe 300 yard load pretty much, if your sending them at 2850 ish fps.
You dont mention if you use the TSX or TTSX.
The TTSX is a better bullet overall as it's wider 'hollow point' and the platic tip, makes it expand more reliably and violently.
ELK are larger and the target has more resistance so the bullets will expand more reliably, and work better on the elk then a deer witch is lighter built.
Let those bulets down in the 2200 fps or lower, on a light bodied deer and you will start seeing delayed kills due to lack of expansion.
Lung shoot it and it will run further then you will like.
The 120/130 ttsx at 3200+ witch is possible from a 284 with a suitable powder, will make that a safe 450-500 yard deer gun.
I have used a lot of 150 TTSX from a 308 win at 2950 fps shot a lot of deer with it, but it's not suitable for use beyond 300 meters really.
It's a very stout bullet and shoulder shots on large moose even, are pass through never found a bullet.
Tried the 150 TSX back when they was new, and have since stayed with the TTSX version, simply because they expand more reliably from my experience.
The 130 gr is a much better bullet though simply because the 308 can't drive the 150 fast enough to have good effect beyond 300 m on lighter game.
And at 3150 fps the 130 gr TTSX has a expands a lot more violently witch leads to faster and cleaner kills.
So using a lower bullet weight then 'normal', and pushing them fast is the way these bullets really shine on game performance.
And of course you don't find fragments and lead everywhere, and they tend to be a lot less messy.