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miclo18d · 05-24-2017, 20:34

Turning someone's head into a canoe, you don't need the round to tumble, but when you're stabbing someone with an ice pick in the heart.... well, I've heard enough anecdotally that when I built mine, it was a 16 inch barrel with polygonal rifling to get a little extra speed. I wondered if I should have gone to 18"...

When I was in, I wanted to be part of the 10in crew, but WTF did I know? I was an 18D. It took me several years of research after retirement to understand internal, external, and terminal ballistics (I knew the effects of terminal). I get the vehicle thing, but the second you step out with your high speed maneuverability, you have pigeonholed yourself. The 77gr BH was designed originally for the SPR, but was found to work well with shorter barrels and leaves the barrel right at around 2500fps out of a 14" barrel, probably will tumble only out to 50-100m.

The accuracy of short barrels is not in question. Barrel length has little do do with accuracy but muzzle velocity has a lot to do with external and terminal ballistics. When using standard supplied ammunition, the main factor is barrel length and then it's the law of diminishing returns as you go past 20"-22". Heavy barrels tighter twist rates better BC projectiles, accuracy hand loads.... it goes on forever.

05-24-2017, 20:34	#19
miclo18d Quiet Professional Join Date: Mar 2012 Location: Occupied Northlandia Posts: 1,697	Turning someone's head into a canoe, you don't need the round to tumble, but when you're stabbing someone with an ice pick in the heart.... well, I've heard enough anecdotally that when I built mine, it was a 16 inch barrel with polygonal rifling to get a little extra speed. I wondered if I should have gone to 18"... When I was in, I wanted to be part of the 10in crew, but WTF did I know? I was an 18D. It took me several years of research after retirement to understand internal, external, and terminal ballistics (I knew the effects of terminal). I get the vehicle thing, but the second you step out with your high speed maneuverability, you have pigeonholed yourself. The 77gr BH was designed originally for the SPR, but was found to work well with shorter barrels and leaves the barrel right at around 2500fps out of a 14" barrel, probably will tumble only out to 50-100m. The accuracy of short barrels is not in question. Barrel length has little do do with accuracy but muzzle velocity has a lot to do with external and terminal ballistics. When using standard supplied ammunition, the main factor is barrel length and then it's the law of diminishing returns as you go past 20"-22". Heavy barrels tighter twist rates better BC projectiles, accuracy hand loads.... it goes on forever. __________________ "The rifle itself has no moral stature, since it has no will of its own. Naturally, it may be used by evil men for evil purposes, but there are more good men than evil, and while the latter cannot be persuaded to the path of righteousness by propaganda, they can certainly be corrected by good men with rifles." — Jeff Cooper Last edited by miclo18d; 05-24-2017 at 20:44.
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