I killed a pile of deer with them from my TC 50cal.
Interesting to me...70gr of 3f shot the same (as far as I shot) as 90gr of 3ft and a PRB. I was shooting Hornady balls and didn't like performance on deer. Weren't exiting broadside chest shots...so I went to the ball-ets.
Performance wise, they didn't seem to do much but they penetrated extremely well.
A penetration story...
I was in a ladder stand waiting for my buddies to wake up. A herd of doe were coming down the ridge right at me. Big ole nanny got to about 30yds and I figured I better take the shot before I got picked off. She was quartering towards me pretty hard. I put the sights on her front right shoulder and touched her off. I watched her take off down the hillside. As she was running I swore a back leg was flopping wildly. She ran 60yds or so before dropping down the ridge out of view.
I felt sick. I knew I saw a rear leg flopping..with a herd or deer running, it was hard to tell for sure...I also didn't think it looked like she was hit hard.
I waited a few minutes and climbed down. Long white belly hair and bone fragments. Anytime I've found bone fragments like that before was a leg hit of some sort. I was sick. How'd I take a rear leg off?
I reloaded and started sneaking on the trail. Well...followed her kicked up leaves. There wasn't any blood that I saw.
I get to where I last saw her and looked down the hill sneaking along trying to get a 2nd round in her hoping she bedded just out of view. As I peeked over the hillside, the leaves were all distrurbed wildly. At the end of that destruction, she was piled up dead.
Bullet went in right tight to the front right shoulder. It came out right between the rear legs and continued on shattering her left rear leg.
I couldn't believe it. That was pretty extreme penetration IMO. Granted, besides ribs, no major bone was hit..
Buddies woke up, helped me drag her back to camp, and I proceeded to kill my biggest buck at the time. Good day in the flintlock woods!