I can get well above 1850 without burning because I use shotgun wad bases. However the riflings are cutting the patch material and once that happens all spin is lost and I get flyers...and I mean flyers!!!

I did however find my good patch material that will take about 1600 FPS with a failure every five shots or so. I made some, what I call, baby snort, a mixture of 1 part Murphys oil soap and 1 part Olive oil mixed. Works well and keeps the bore fairly clean.