If it was me I'd buy new, that way you know exactly what your getting, no surprises. It seems like you prefer TC? A Triumph would be a excellant choice, I watched a video of a guy shooting one and at 200yds he was almost touching every shot, seems like a long range hunter to me.
AS for a used one, as mentioned above a Bore Light and commen sence will get you one, also the age of it will give you a clue as to what the insides have been put through.
Dont kid yourself, once hooked on MLers there is no (just one more) you'll get more. I have the UPS Driver trained to not stop at the House if My Wifes car is in the driveway or befor the time she leaves for work,LOL!
Good Luck now that you've been bitten.
(BP)