Will see what CPUM 10.5gr are doing,, possibly< +/-500FPS.
Barrels that throw flyers can be attributed to by inconsistent pellet fit/shape, crooked or rough crowns, bad piston seal or breech seal, shooter error <LG> XD
I have been playing with the idea of low power on springers for a while and while yes, shortening the barrel is beneficial as to minimize drag, i find it also that spring rate matters as well. Since springers and rammers only can delivere the same volume of air per shot, is the amount of drag and the point of resistance in which the pellet begins to slide thru the rifing that is difficult to get just right. One little trick that i have used on all my shorter barrels and low power guns is actually "cleaning " the rifling with something that is heavily abrasive as to "wear" the lands and grooves a bit and then polishing the bore as much as possible. I'll run a snake through 200 to 250 times, and have seen consistent results of:A) Velocity increase between 3 to 5%, in all applications.B) noticeable group tightening (shoot 10 groups before and after, showing after groups avg to be measurably smaller).