I shoot a Remington Model 7 .243win with an 18" 1:8 barrel. It shoots 5 shots into a dime sized hole at 100yds using I4350, Nosler 100gr Partitions, CCI200 primers. H4350 opens the grouping up to a half dollar size at 100yds. It holds a 2.5" group at 400yds. Some of that could be me and the rifle being so light.I didn't have it shortened to 17". It was 18" to begin with and had a horrible rough spot at the bore so 1" was removed to clean it up and see how it shot. Also the ranges we're talking about aren't really that long of range are they? It seems like a 1-9 twist should stabilize a 100 grain 243 even at 17", or am I missing something?