What kind of barrels the military use in the front… a 1 in 7 twist or the common 1 in 9 twist ,there are many companies supplying or troops…
1 in 7.
M4 supplied by Colt’s
M16 supplied by FN-Herstal
Thanks for the reply i just want to learn more about the twist in the barrels…
overview:
the longer the projectile, and faster the spin necessary to stabilize it. bullet weight generally correlates to bullet length, therefor there are general weight/twist-rate combos commonly accepted. <55, more than 1/9… >55, 1/7 or 1/8 for some competition purposes.
1/7s will generally stabilize FMJs of any weight, because they hold together well. open-tips, ballistic tips, other varmint loads, often require slower twist rates- 1/9 should do it, but these guys sometimes use 1/12 or even 1/14.
bullets spin at an extremely high RPM… IIRC, m193 spins at around 300,000rpm from a 1/7 twist barrel… the right twist/bullet combo is important to keep them from shredding and/or destabilizing
read the technical stickies for more, and more in-depth info on all things basic
and as to the number of companies supplying barrels- there aren’t that many, and they all produce barrels to the same spec and standard. and they’re all 1/7, except for some SDM-Rs that i think use 1/8