Thank you all for the replies. Research using European ammo has shown an increase in velocity from 2330fps to 2475fps in a 22" barrel over a 16" barrel. Murray, you got it right,thanks. I know that the powder charge, in a x39, does not burn completely, because the muzzle flash is caused by unburned power igniting when it contacts the oxygen in the air,causing it to ignite. Its the quality of the ammo that counts. Surplus ammo can show that much difference round to round from the same box.