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6/21/2017 8:25:40 PM
Posted: 2/28/2001 7:43:44 PM EDT
be shooting some standard ammo at? Well, here is a post of some good info. It was originally posted by TOM.32 from the old AR15 board - just a post that I saved - I finally took the time to chrono different barrels for each length that I have and some different ammo just to see what the results would be. No real surprises. Chronograph, Oehler Model 35 w/ 3 screens distance 10' 10 shots each barrel with each make of ammo 85 degrees 40% humidity (approx.) 1290' above msl Barrels, 20" Colt 1/7 Govt. 16" Colt 1/9 lightweight 14.5" Colt 1/7 M4 11.5" Colt 1/7 commando 10.25" Colt 1/9 lightweight (16" cut down) Lake City M193 1997 20" - 3255 fps 16" - 3145 fps 14.5" - 3075 fps 11.5" - 2884 fps 10.25 - 2767 fps Q3131A 1999 Lot PF20 20" - 3152 fps 16" - 3051 fps 14.5" - 2951 fps 11.5" - 2732 fps 10.25" - 2605 fps IMI M193 20" - 3131 fps 16" - 3032 fps 14.5" - 2917 fps 11.5" - 2726 fps 10.25" - 2598 fps Rem UMC 20" - 3122 fps 16" - 3001 fps 14.5" - 2878 fps 11.5" - 2705 fps 10.25" - 2499 fps No misfires, ftf's, chambering, or extraction/ejection problems. Individual results may vary. I have done a few barrels at other times when it was colder (55 degrees and 70 degrees) and the Lake City was closer to the others in velocity. It seems like I read somewhere that the powder used is more temperature sensitive? I thought about doing some Lake City M855 but didn't think I would have time. Might try that next time.
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