Many people claim a 26" barrel or longer is necessary to burn off a full charge of 150 grains of powder. I would not know, I never tested that much powder charge enough to make an opinion. A 22" barrel I know for a fact will burn off 110 grains of powder as I never see any unburned powder on the snow in front of it. I have shot 120 grains of powder out of a 24" and never saw unburned powder.

The big question concerning barrel lengthcenters on; if the barrel is too short in direct correlation to the amount of powder making uo the over all charge, there becomes the possibility that the ignition time will not have enough barrel length to have sufficient time to get the full benefit from that powder charge.