Congratulations on the deer!!
I have used the 200G and 225 FTX on a few head of game in 45 Colt and 454 Cassull... BOTH can be fragile. the 450 has more HOP than BOTH.
The 225 shoots REAL well in my guns 450 included. I have had the 200G come apart on Coyotes! I haven't lost a deer with them and different folks judge a bullet problems differently. I do not consider these bullets to have failed, but in same regard, I will DEFINEATELY treat them differently and likely not choose EITHER as a Big Game Bullet in the 450.
When judging a big game hunting bullet, I subscribe to complete thru and thru penetration or I am not happy. For me, Defensive and Varmint bullets STAY inside and or "explode".
The Hornady XTP
MAG is a better choice, but still the 450 Can outrun its max recommended velocity. BUT enough of us have used them in muzzle loaders are close ballistics and know the bullet works pretty well. The 250 FTX and the 300G made for Muzzle loaders are pretty good/safe bets. People have complained about bullets "blowing up" but MANY variables exist, like distance, whats actually hit by the bullet (Was bullet upset by strikes BEFORE impact) So take them with a grain of salt.
I personally saw what one 250 FTX and one 250 SHOCK WAVE will do to broad side shots on 140 ish Whitetails @ 40 & 140 Yards. Thru and thru, ribs both sides and Quarter & Nickel sized entrances and silver dollar + exits.
The 250 Gold Dot Bullet took a base of the neck shot form 25 yrds on a 200# buck a few years back from my 454 carbine. That bullet never exited, BUT It pulverized a vertebra and still penetrated 12+" of muscled rutting buck neck to be found under the skin on opposite side, INTACT! I was impressed with that bullet!
As to powder coated lead bullets. that powder coat, if properly applied is a good Jacket. It encapsulates the bullet, allows for much higher velocities and excellent performance. Some worry about the gas systems of firearms and I tend to agree. But MANY shoot them without issue.
I cast and powder coat my own 300G bullet and load it to 1800 fps and it shoots MOA from my RARR BOLT gun. I would NOT hesitate to take large game with this loading.
CW