XP is right on the money with his reply. If you need long range handgun hunting advise, SScoyote and XPhunter are THE two to talk with.
This summer they will be going for the one mile market with specialty built XP-100s in 7mm bore. I believe Xphunters is the 7mm WSM
while I am building Sscoyotes XP-100 chambered for the 7mm-270 WSM wildcat. Many may ask why we would use this wildcat. Simple answer, using Norma 270 WSM brass for its quality(the 7mm WSM is 0.030" longer in headspace length).
My 6.5mm WSM is built on a 15" Lilja 1-8" twist barrel and fitted with a Holland QD brake. The muzzle diameter is .700" and is a straight taper shape.
It wears a Burris 2.5-7x handgun scope and has a Fajen laminated stock which I fitted with my own V-Block bedding system. Extremely accurate handgun. Will average in the .3"s and .4"s at 100 yards.
I do not know the exact weight of the handgun, probably in the 4 lb range or slightly more.
Recoil is less then my 221 Fireball XP-100 handguns, as far as felt recoil and muzzle jump. The blast is certainly more.
Performance wise, I will be testing some of the Wildcat 142 gr ULDs here very soon. I used the 120 gr Ballistic Tip this last hunting season loaded to 3050 fps and this load cleanly harvested a big mule deer doe at +330 yards with a single shot breaking both shoulders.
With the proper bullet, these hadnguns are easily capable of consistant hits out to 1000 yards. The problem is optical power. Traditional handguns scopes are not that great. The Burris 3-12 is about the best conventional handgun scope for longer range shooting. For serious work, you will need a converted rifle scope.
As far as the Encore goes, forget it with the WSM class of rounds. I do not even recommend it with the standard belted magnum round.
I have a beautiful Virgin Valley 15" Encore barrel built on a Lilja 1-9" 7mm barrel in stainless steel. I believe the muzzle diameter is in the .800-.825" range. The barrel is a tack driver, 3/8" groups is easy to get with this Encore.
It is chambered for the very short and fat 7.21 Tomahawk from Lazzeroni.
Only problem, you will get two firings per case, MAX. At +$2.00 per case, this is not acceptible. So it sits in the gun safe. I should sell it but I just can not ethically bring myself to pass it on to someone else.
Go with the 280 AI as XP stated. This will provide the most performance for the bang. Another option would be the 280 JDJ which is een higher performing then the 280 AI but much more involved as far as forming cases go. It also uses the '06 case size which is the largest I recommend for the Encore handgun.