Welcome! No sub forum for SML's. I put together a SML a couple years ago using a remage barrel from Arrowhead. I haven't shot it past 200 yards but it's very accurate. Currently shooting 275 nsr's from Arrowhead.
Dougs is fine and with digging a lot of info. I have shot a smokeless muzz for years. Dont' shoot it a lot. Stupid accurate with lots of combinations. Spot on at 500 and super easy. We have had them on steel at 1000, but it gets a bit tricky there and it runs out of steam a LOT.