I have to do some figuring on this, as I want to use HPA, if I can safely do so.
I also ran into another problem,
When I went to mount the Mueller 4.5x14x40mm APT scope and when I attempted to mount the 3/8 dovetail rings,
I could not get the rings to fit down on top of the action, when centered on top of the action,
the ring base would not did not have enough height to grab into the action grooves properly.
I tried several different make of 3/8 size rings and none of them would fit, due to the radius of the action etc,
all the ring bases I tried were flat across the base of the rings, just above the clamping ears etc.
I think I will need either med or high rings to clear the top of the barrel for this scope,
Is there rings that have a radius cut into the ring base, to fit the radius of the action??
I like the Millet Angle lock rings for their adjust ability to center the scope etc, but can not find any.
Any other suggestions or Ideas?