Agree 50 yards is best for initial 22 testing. If you're doing 0.3" then it sounds like you know what you're doing, especially if that's with 22! Even if the barrel has been abused sometimes they can be made better by cutting off the bad spot, assuming the bad spot is towards the end and you have usable barrel left. Also the 1/8 bedding around the action sounds strange. Sounds to me like someone was trying to "fix" something. I'd try it at 50 and also try ammo other than eley, and like already mention shoot a bunch of rounds of the new ammo before expecting the best groups, then go from there. If you need a new barrel at least you'll know it'll last a long time.