I can't answer to the fellow with 1;7 and 1;8 twist other than he must have extremely barrels. The original M16s had 20" barrels with I believe 1:16 twists and they were shooting mostly 62 gr. bullets that wouldn't stabilize in flight. They changed to 1;12 twist which still wasn't spinning the round fast enough for it to stabilize so they switched to 55 gr. bullets and the stability and accuracy improved.
If you google 5.56 terminal ballistics in gel, you'll get an idea of what happens when a round hits a human body. Most of the time, because of the speed of the round they fragment. Mike
permafrost wrote:
Moldy,
this tumbling and lose of accuracy was pointed out by an old gunny sgt. in Veitnam..
It seem this was a feature in the original design.. had 1;16 twist in the rifling. changed a bit later to 1;12.. For the military..
commercial AR-15, which are M-16 made cheaper, often still have the tumbling problem..
If you look at a gun site on line you can find endless argument about it..
My opinion---I using an older version or a newer cheap version of the rifle. Tumbling will be common and has been found in several of the k*****gs..
Use a modified military or high end version, then not so much..
My thinking is that both you and Dr. Evil are right.. and I think that most users are at the cheap end of the scale.. So, yes, the tumbling makes the round more devastating..
Sample from---https://thefiringline.com/forums/showthread.php?t=587626
Tumbling bullets in the AR-15
Following the shooting in Virginia, before it was clear what weapon was used, another fellow surmised it was an AR15 and related the devastating wound was probably due to the bullet "tumbling."
It is my impression that "tumbling" dates back to the Vietnam era and the introduction of the AR15 with a 1:14 twist that stabilized a 55gr bullet until it hit the target, then tumbled due to yaw and instability. At greater distances the accuracy was poor and the twist was changed to 1:12. I have a 1:7 twist and I don't see any keyholes at any distance. So my position was if the shooter used a modern AR15, tumbling was not part of the equation.
But the other fellow says he has both a 1:7 and 1:8 twist and both rifles tumble his bullets of ALL weights.
What do you other shooters think?
Moldy, br br this tumbling and lose of accuracy w... (
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