I tried them for the first time 16 years ago. It was a 130 BST from 270 Winchester. I was not impressed. If bone was hit they came apart with little penetration. The same year I shot a Muly doe at ~60 yards. She went straight down from a behind the shoulder shot. The bullet destroyed the heart, but did not even bruise the offside ribs.
I remember a friend using them in his 300 Win Mag. He shot the 165 and 180s. This was several years before I tried them. Rarely did the deer die right away, but they had huge surface wounds. A finishing shot was often necessary. The bullets were well placed too.
A few years ago I heard that Nosler had toughened them up so I loaded up some 120g BT in my .284 Win to 3200 fps. The first deer was a whitetail buck at 35 yards. At the shot he never missed a stride as he walked through the timber. I thought I had missed until we heard him hit the barbwire fence separating the property we were on from another. We found him stone dead. The bullet went in low as I was shooting slightly uphill and destroyed the heart, but did not exit. We found it the next day while butchering the deer. It did not have its core, but had mushroomed well by evidence of the jacket.
The next was a Muly does at 283 yards. She was broadside at the shot dropping right there. When we got to her we saw a hole on the offside of her head. I thought I had messed up, but on dressing her we discovered the bullet had deflected off the shoulder, traveled through the neck and exited her head. Quite as bit of penetration, but the deflection worried me.
The last I saw the BT used was this year. It was used on a Muly bucks at ~ 250 yards. Perfect shot placement behind the shoulder with an exit. The deer trotted forward about 30 yards and died. Again lots of internal damage and with an exit. It looked like damage from any other cup and core bullet.
They have proven to be some of the easiest bullets to shoot well and after my experience with them I am giving them another shot. Time will tell.
