I've used the .40 cal 200 grain XTP's with great success on whitetail. As far as I'm aware, the 180 grain XTP isn't really structurally different than the 200 grain - just a little lighter/shorter. I'm sure it would perform very well on whitetail at moderate velocities - I'm not sure if I'd try and push it with a max load.

I've had the jacket separate from the core with the 200 grain XTP only once, and I still got full penetration. That time was a coup de grace shot from 3 yards away - 80 grains 777 and the 200 grain XTP. The XTP fully penetrated the chest cavity diagonally - I found it lodged in the far side hide. The jacket had separated, but the bullet still did its job.

All other shots with the 200 grainer were complete pass-throughs. I would guess that with the 180 grainer you may not always get complete pass-throughs, but it would still do a good job on deer out to 100 yards or so.

Note: Another possibility with your .45 barrel is to getsome MMP.45/.357 sabots and get a box of .357 mag. bullets (XTP, Gold Dot, etc.). Shouldbe fun