I used 18gns of Trailboss which had some space left under the bullet. I figure these were subsonic (1000fps?).

I'm also going to try AR2207 since velocities are similar to AR2205 but you use a little bit more of it. I've also been told that 2207 lights up easier than 2205. My last 2205 load gave a slight hangfire and I've decided to steer clear of fillers (I'm using magnum primers too), so 2207 should help.

I've just bought a set of Warne QD mounts and have installed an old Tasco 4x32 scope that I had lying around - it should stand up to the reduced laod recoil okay. The Warne mounts are schmicko!