Re: 175 s in a 20 "
Most (if not all) of my 308 loadings are for my Super Match M1A. It shoots 175s great at the normal 2550 area. But in a bolt gun you could get a bit faster.
This should give you an ideal. In working with my granddaughter in her science project, we cut a 308 barrel down 2 inchs at a time to 16 inches to see what the differance would be. We used Hormandy factor 180 grn cor-locs (the project was about hunting rifles and energy differant barrel lengths). Here is a look see, I would think you could get simular velocities with the 175s.
The first col. is barrel lenght followed by Vel @ 100, KE @100, Vel @ 300 and KE @ 300 yards
<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">26 2826 fps 3,192 2240 2,005
24 2722 fps 2,961 2149 1,846
22 2713 fps 2,942 2141 1,832
20 2677 fps 2,864 2109 1,778
18 2654 fps 2,815 2089 1,744
16 2552 fps 2,603 2000 1,599
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