With the Rifle,
Have taken two bulls at angles like this.
One September in Idaho.... with a hard quartering angle at 50 yards. Placed the crosshair on the point of the bull's shoulder. Was trying to break a bone and did so. The load was a Win Supreme 160 grain Fail Safe load from my .280 Remington. Result was a 1-shot kill as he boogied down his back trail and out of sight. Found him very dead after a 70-90 yard sprint. Had faith that the bullet from this load would hold up. Scope was on 2X, I was kneeling and pretty steady (considering). Best eating bull ever!
One year before in New Mexico: Nearly facing me with head down feeding hard. I put the crosshair inside the shoulder nearest and fired between his main beams.at the base of his neck. Feeding towards me, once he cleared some branches I took careful aim. At the shot, he buckled and sprinted out of sight. Had every intention of following up until the bull was down. He did not give me a chance. Same 160 grain Fail Safe load exited (opposite side well back) after passing thru 3+ feet of this large bodied bull. Reloaded mag to full capacity and followed up after about 3-5 min. Jumped him up at 20 yards buried under a western cedar with low-hanging branches. He could not run and I put a round thru his ribs. He staggered and eventually fell kicking and screaming enough to unnerve our horses. It took two more shots (both to the head) from a .357 revolver to finish him. The 1st hit from 110 yard should have been fatal, but the elk just hung on to life, just refusing to die. Exit wound was full of grass/feed and looked like a 4-blade broadhead made an exit. It was obvious the bullet passed thru lung and torso doing heavy damage. Exit wound was near the last rib on the far side catching the leading edge of the rumen. On this shot (scope set at 7X) I was sitting on my butt (elbows on my knees) had a good 4 minutes to calm myself with the bull in sight.
If I hadn't seen the bullet performance on the New Mexico bull, I might not have had the confidence to shoot thru a shoulder bone on the second (Idaho) bull. A Swift A-frame, Barnes TXS, TTXS, Trophy Bonded Bear Claw, or a similar stoutly build projectile could IMO do the same thing. Maybe not however, with a soft point (cup-n-core), Core-lock, or a power point load.
The Idaho bull was responding to calls and came in screaming. He was looking for a challenger and might not ever turn. In both cases the wind was not steady enough IMO to risk waiting for them to turn broadside. I made a judgement call not to wait for a perfect shot that might not happen. Well placed shots under 100 yards with capable cartridge's fired from a rifle you are comfortable shooting, should be an attainable goal.
LaGriz