Are you going to use a rifle barrel or a pistol barrel? I've shot deer with an AR-15 in a 6.8 spc and if you put the bullet in the right place it will work fine. If you miss your spot by a bit, it is a very sloppy deer caliber. I'd definitely go with the rifle barrel and not the pistol.
I believe it would be fine. Seeing how it was developed for the 16 inch barrel M16 using it a 14 inch contender I believe your powder burn will be about right. Also if your discouraged about fps or foot# of energy. Do asearch on 270win long range kills and cross check your max range with pistol to longrange kills and compare the ft#'s . If that makes sense.
I've used my Contenders in 7mm TCU and 7mmJDJ#2 from 25yds out of a treestand to 100 through the Hardwoods of NW PA. I would only shoot to ranges you can consistantly hit the boiler room and were energy is acceptable. Trigger time is key w/successful pistol hunting and steel is a great way to practice. It can be very rewarding and a change of pace.