Sagetown
Farmer and a STIHL
Stihl doesn't use the "small spline", but use their own "mini spline" instead - but all but the 360 out of those saws comes with a spur sprocket anyway.
Replacement drums with a splined hub and a rim are availiable for at least some of those saws though, and if they are Oregon they may have the "small spline". If it is Stihl, it is either "mini" or "standard" (often called large).
This is true. I have a MS270. Ordered the small spline for it. it was too loose. Went to the Stihl dealer and he gave me the Stihl Mini spline, quite a difference.