Thanks guys, good advise. The reason for "no compression" is because I mainly use 777. I haven't bought the gun yet (I shoot a Pietta Remington). 15gr sounded a bit anemic for a 36, but 20, in a 6.5" barrel sounds much better.. Maybe keeping the load at 15gr for practice would make the gun last much longer, but it would be nice to have the option of loading 20gr of 777 occasionally..