[Sir Krustin]

Lets here from some of you, continuing the discussion from other more sober threads-- I'll start this off....

MagiK said:

You must not be watching the same gun shows that I have then And I do know that they are absolutly crap for real long range shooting. It isnt the barrel or rifeling that causes the tumble by the by, it is the standard round that is fired that does that.

I respond:

Actually, read SirT's post he mentions a few slightly modifed match-grade AR-15s that are used out to 1000m. He says it better than I could.

Also, you don't understand the significance of what I said...rifling is very, very important to the accuracy of a round. A tumbling bullet is NOT ACCURATE AT ALL! A round fired from a rifled weapon DOES NOT TUMBLE - the bullet is stable, like a gyroscope, because of it's rotation. Assault rifle bullets -- from *any* rifle just do not tumble, period. I once read an otherwise reputable magazine state that "small caliber assault rifle bullets tumble through the air, causing much more dramatic wounds when they hit." Another source didn't quite go to this extreme, but did state that the AK-47 round had a "very complex design with an air bubble in the tip that shifted the center of gravity back and made it more likely to tumble". Rubbish.

Bullet tumbling is a fascinating subject where a tremendous amount of misinformation has been spread. As I said in the other thread, the M-16 got a reputation for tumbling rounds from older M-16A1s (1 in 7 twist) that had worn out barrels. The combination of a relatively mild twist and lack of a tight fit between the lands and the round result in the bullet receiving very little rotation before they leave the barrel. Result: tumbling round with VERY low accuracy and a range of no more than 100m!

The Dr. Fackler I quoted is a very respected ballistics researcher at the WBL, and is in fact one of the most quoted experts in the field. He did some research into the matter of the M-16 and the tumbling round. As I said, he discovered that small arms in good repair DO NOT TUMBLE -- unless they hit an obstruction. Once they hit this obstruction, they tumble exactly once, then resume a stable trajectory. He verified this with multiple sheets of paper arranged in a series before and after a target that offered an obstruction to the round. He then fired a round through these sheets of paper and examined them. The sheets of paper uniformly showed a perfect circle, until the round reached the obstruction, where the paper showed an elongated hole (known as "keyholing") showing that the bullet tumbled. Further sheets in the series showed circular holes, proving that round had stopped tumbling.

The interesting part about this whole study was that *ALL* bullets will tumble when hitting an obstruction like this. Dr. Fackler once did a demonstration starting with a .22, moving on up to the popular .223 and 5.45mm rounds, culminating with the powerfull browning .50 (fired from an M2HB) and all showed the same behaviour!