I finally got the high rings that'll work, and took my 455 Christmas present out to the range yesterday for the first time with the .22 barrel (put a Bushnell Banner 4x12) on it. To say I'm highly satisfied would be an understatement. Fantastic trigger, smooth action, and a tack driver. I was able to shoot 1" groups on the 100, with an intermittent crosswind, and cheap Federal ammo; with only the forestock on sandbags. The rifle is obviously capable of better accuracy than that, because that's the first range rifle time I've had in 7 years.
Murphy was an optimist.