I'm up to trying out a 19.5grn load behind a one ounce jammer xl-1 wad. Been loading up to this by starting out at 18grns. Not too concerned with 'blowing' up the shot pattern some. Just trying to get to the target as fast as I can. Jim
It would be more helpful to know the rest of the load details. Hull? Primer? I would also suggest checking the data posted on the manufacturer's site. That load might be at or above the max, depending on what the rest of the story (LOAD) is.
Jim- Please consider your thoughts on "getting to the target as quickly as possible". With a calculator, and ignoring the deceleration of the shot, figure out the time difference for shot traveling a 1150, 1200 and 1250 ft/sec to travel the 90 feet before it breaks the target. With a bit more research, you can see that the faster shot decelerate faster than the shot moving slower.
Rather than getting to the target as fast as possible, I would suggest considering such things as pattern effectiveness and recoil are much more important than time to the target.