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1_click_off
06-11-13, 23:50
Was screwing around trying to figure out bullet RPM and then found this formula.

MV x (12/twist rate in inches) x 60 = Bullet RPM

Amazing the RPM on projectiles and the fact they can hold together. If I was anymore of a nerd I would figure out the centrifical force on the jacket, oh wait I am. I am going to run some numbers on that too!
Tzed250
06-12-13, 04:48
The max RPM some bullets will take is why some need slower twist barrels. A 40gr varmint bullet fired from a 1:7 barrel will in most cases turn to dust a short distance from the muzzle.
markm
06-12-13, 07:48
A 40gr varmint bullet fired from a 1:7 barrel will in most cases turn to dust a short distance from the muzzle.

Anyone shooting that combo is about 16 oz short of a pound. :rolleyes:
Tzed250
06-12-13, 09:02
Anyone shooting that combo is about 16 oz short of a pound. :rolleyes:

True, but I'd bet its been tried.
markm
06-12-13, 09:09
True, but I'd bet its been tried.

Shoot! I don't even like shooting 55 grain anymore. :p
Tzed250
06-12-13, 09:21
Shoot! I don't even like shooting 55 grain anymore. :p

The 5.56/.223 has truly evolved in its 5 decade life.
markm
06-12-13, 09:25
The 5.56/.223 has truly evolved in its 5 decade life.

You aren't kidding. Our bolt gun riflesmith can't wrap his head around heavies in .223. He sounds like me 5 years ago. :p

I've purged almost all my m193 ammo and am replacing it with 75-77 grain stash ammo.
The_Count
06-12-13, 13:05
You aren't kidding. Our bolt gun riflesmith can't wrap his head around heavies in .223. He sounds like me 5 years ago. :p

I've purged almost all my m193 ammo and am replacing it with 75-77 grain stash ammo.

Mark, be careful, it sounds like you might be evolving as well!:p

Next thing you know you'll have a tube on your carbine.
markm
06-12-13, 13:17
Next thing you know you'll have a tube on your carbine.

And start shooting matches? :eek: