Hi Please allow me to introduce myself. My name is Rob I am in the US Army stationed in Europe. I have a .50 BMG (Barret M82) and a .375 Cheytac that are my long range Working Tools. I have yet to fire the .375 Cheytac as it is not yet completed. My Gunsmith is using 300 grain Barnes X bullets at 3500 FPS in it as the Sierra 350 Grain bullets turned out to be sub par When I was in Iraq for the last rotation (MNC-I 05/07) I got hooked on your forum and found it to be a mountain of knowledge in the longrange Craft. Now for my question. I am having my .338/.378 and .300 Weatherby Mags Rebarreled and would like to know what kind of velocity increases I should expect when I increase the barrel lengths of these two weapons? The .338/.378 is a Accumark and the .300 is a Vanguard. I shoot 250 grain pills from the .338 and 180 grain pills from the .300. Thank You for any info you can give me Very Respectfully Rob P.S Any Cigar smokers on this forum?