I know it seems everyone likes to run 1/7 twists and heavy/long premium bullets at 5.56 pressures for everything from social work to pick your favorite Mad Max/ZA happy place. And this seems to include pistols and SBRs.
I stock 5.56mm m193 in either Federal or PMC X-Tac when I can. I'll take two or three boxes of those to a single box of premium stuff. If zombied, pigmy, goat people overrun us tonight or tomorrow, that is what is in my mags for my rifle. It's what I'll practice and shoot with. As I build my pistol it will be what I'll be shooting. Just want to make that understood. I won't be stocking "the good stuff," and I want to shoot what I'll stock.
Now going back and studying Stoner's original design the M193, 55 grain was intended to be shot from a 20" barrel with a 1/14 twist. This just stabilized the bullet enough to give good accuracy, yet according to the history had "devastating effects." The change to 1/12 was because the Air Force was having issues with stabilization affecting accuracy in severe cold conditions way up north. So everything got changed as a compromise and the round diminished a little on the business end.
Looking at this and contemplating an AR pistol with a barrel in the 10-11 inch range and with an understanding that for any potential social work it would be at very close ranges. Room to room and across the street distances with 50 yards being about max and really more in the 15-40 yard range. I have a scoped AR rifle if I need to work to the end of the street or street to street. 100 yards would be a very long and very rare shot except for recreation.
Looking at this and the fact that the original very slow 1/14 from a 20" barrel seemed to put the 55 gr M193 at it's most destructive, which if I punched the right keys on the calculator means the bullet manage 1.42 revolutions in a 1/14 twist barrel, it makes me ask this.
Given the same M193 round exiting a 10.5" barrel with a 1/9 twist (1.17 revolution) and the reduced FPS from that barrel and running just above the fragmentation threshold (in more stabilized twist barrels too) would that perhaps somewhat replicate the just stabilized effect of the 1/14 original twist?
In other words at very close range would M193 from a 1/9 twist, 10.5-11" barreled pistol (or SBR for you Tax Stamp guys) be effective? Would it be enough less stable to yaw more likely early in tissue?
I stock 5.56mm m193 in either Federal or PMC X-Tac when I can. I'll take two or three boxes of those to a single box of premium stuff. If zombied, pigmy, goat people overrun us tonight or tomorrow, that is what is in my mags for my rifle. It's what I'll practice and shoot with. As I build my pistol it will be what I'll be shooting. Just want to make that understood. I won't be stocking "the good stuff," and I want to shoot what I'll stock.
Now going back and studying Stoner's original design the M193, 55 grain was intended to be shot from a 20" barrel with a 1/14 twist. This just stabilized the bullet enough to give good accuracy, yet according to the history had "devastating effects." The change to 1/12 was because the Air Force was having issues with stabilization affecting accuracy in severe cold conditions way up north. So everything got changed as a compromise and the round diminished a little on the business end.
Looking at this and contemplating an AR pistol with a barrel in the 10-11 inch range and with an understanding that for any potential social work it would be at very close ranges. Room to room and across the street distances with 50 yards being about max and really more in the 15-40 yard range. I have a scoped AR rifle if I need to work to the end of the street or street to street. 100 yards would be a very long and very rare shot except for recreation.
Looking at this and the fact that the original very slow 1/14 from a 20" barrel seemed to put the 55 gr M193 at it's most destructive, which if I punched the right keys on the calculator means the bullet manage 1.42 revolutions in a 1/14 twist barrel, it makes me ask this.
Given the same M193 round exiting a 10.5" barrel with a 1/9 twist (1.17 revolution) and the reduced FPS from that barrel and running just above the fragmentation threshold (in more stabilized twist barrels too) would that perhaps somewhat replicate the just stabilized effect of the 1/14 original twist?
In other words at very close range would M193 from a 1/9 twist, 10.5-11" barreled pistol (or SBR for you Tax Stamp guys) be effective? Would it be enough less stable to yaw more likely early in tissue?
