The bullet that the OP was using was particularly light for caliber. 7mm 120 grain bullet. So pretty dang low sectional density. That’s why they didn’t get an exit. With an exit, and two holes to drain air pressure and blood that elk would have went down sooner. With a Barnes type bullet you need enough speed to get full opening of the pedals but also enough weight to poke two holes.
I shot a big bodied old mule deer at 540 yards with a 168 grain Barnes .30 cal bullet. Quartering away and it exited through the shoulder. Animal expired within 20 yards. They can definitely work but for example the 25-06 is an amazing deer round but I don’t think I’d have had the same outcome had I been using the 90 grain 25-06 load. That said with a hammer, cutting edge, etc… type design I’d go back to having no problem with the 25-06 for that application.
Thank you for complete breakdown. I never gave much thought to bullet selection always just used the same thing but times change and the Barnes had some positives I was hoping to take advantage of. I also realize Im using a factory loaded round and looks like LRX not the TTSX.