Newbe advise

[roto-prop]

I have taken more deer with my Browning Lever action chambered in .308 , The 6x6 white tail I have mounted on my wall I took with that gun at about 400 yards. I would be losing about 50 feet per second at the muzzel dropping from 20" down to 18" but with the 6.5 grendel I should not lose any accuracy just a little volacity. I rather doubt that I will ever try to take any game beyond 600 yards. Any shooting that I do beyond that range will be to punch holes in paper the 50 feet second loss going 18" instead of twenty is not that critical to me if it was I think I would go with a 24". But on the other hand when I am out hunting the differance between the 20" and the 18" will be quite real as far as managing the rifle goes. I would like to get a nice muley to go with my white tail with this gun. When I was trying to decide between midlength gas or rifle length gas my reserch showed the optimum dwell time on the ar15 to be about 0.200 mila second on the 18" barrel the midlength gas gives you about a 0.234 dwell time and a rifle length gas port on the 18" barrel gives you about a 0.131 dwell time. The mid length gas port is closer to optimum although just slightly longer than the 0.200 optimum dwell time. I will fine tune " slow the bolt and carrier down slightly" with a h3 buffer and a ajustable gas block. There is a very good article on ar15 barrels that explains how the ar15 gas system works and explains the dwell time much better than I am able to it has graphs and tables very good reading if you want to understand how the system works so you can actually make a informed decision. here is a link to it. http://www.ar15barrels.com/prod/operation.shtml