Got to shoot the 53 and SP-101 yesterday...
The Accurate 31-120S is a little too heavy for both guns...at 10 yards much too high...and this is with the rear sight all the way down.
Tried AA-7 with the 85 grain Hornady XTP and is right on the money with both guns. 9.0-9.5-10.0 were tried. At 10.0 extraction was a little firm with both guns so 9.5 grains is top with this bullet. Didn't have time to chrono them. Will be trying AA-9 and H110 shortly... This was 6 of each powder weight at 10 yards. Was mainly checking for pressure and POI not accuracy...
Also have a 90 grain LBT Gas Check bullet to try....
Bob