I killed a small bull elk this season with the 135 SBD2 out of a 6.5-284. The shot was only 150 yards and did not get an exit. HOWEVER, the bull was HARD quartering toward me. At the shot he dropped so fast I couldn't believe my eyes. Now I say I didn't get an exit, but, the bullet did make it into the guts so I'd say it traveled at least 3-4 feet of elk after breaking front side shoulder and spine. So I'm happy with the performance. I also shot an average Midwest whitetail last fall, entrance was slightly over caliber diameter and exit was about 1-1.25" complete pass though broadside at around 140 yards.
Side note. While on the elk hunt I killed 2 coyotes, both were over 400 yards, The first dropped immediately, the second was 480 at a fast trot going away, He did a few spins before I hit him with a second round and he dropped also…