A friend used the FTX in a .30-30 and went back to the 170 grain FP, he wasn't happy with the penetration after a couple of kills, and I've seen several instances where the .45-70 had more expansion(damage)/less penetration than the 300 grain FPs I use. (Though the Hornady 300 FP gets a little frangible above 1900 fps.)
Not that it was bad, they killed well enough. It's just the the guys using them were used to more penetration, and I never got away from the bullets I am using.
There is nothing wrong with accepting the type of performance they have exhibited, it's just not what I want, so I'm not going to say "Oh, they don't work".
They seem to work well, and probably quicker than a hard cast. There's two things I've found deer like to react to, that being speed and expansion.
