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eddiebritz
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Rate of rifling twist on handgun stopping power.
eddiebritz
New MemberPosts: 1 New Member
Hi All,
There is a heated debate going on at my shooting club regarding the role that the rate of twist (bullet spin/rotation) plays in handgun "stopping" power.
Some members argue that the rate of twist is a major factor in the stopping power potential of a handgun.
According to them the high rotational speed of a handgun bullet (close to 50,000 rpm in the average 9mmP handgun with a 1/16 inch rate of twist) have a tremendous effect on a human body when hit by that bullet. One such member even entertained us by giving a demonstration with his portable power drill and a cup of water by plunging the spinning drill bit into the water - the splattering of the water was spectacular indeed !
The opposition argued that the rate of twist does not play any part in the stopping or hitting power of the average handgun bullet and have very little or no effect at all when hitting the human body. (they were not able to give us a demonstration to support their opinion !)
The leader of the opposition offered the following arguments to counter the arguments of the "pro-spinning bullet" faction:
1) The average depth of the human torso is about 12 inches deep. A bullet (from a gun with a 1/16 rate of twist) that passes through a human torso will only do about 1 complete rotation for every 16 inches it travels, which means that it will not even do 1 complete rotation in the distance it travels through the body - hardly likely to cause any spectacular effect or to contribute very much to the hitting/stopping power of that bullet?
2) The bullet spins at nearly 50,000 rotations per minute (833 per second). A bullet moving at 1100 f/s passing through a human body will not take one minute or one second to pass through the body: it is inside the body for less than a small fraction of a second? The bullet will only do a few full rotations in that fracture of a second - again hardly likely to cause any spectacular effect or to contribute very much to the hitting/stopping power of that bullet?
Not being an expert myself I would appreciate the views of the real terminal ballistic boffins on this topic with reference to any research done on the subject.
Kind regards.
There is a heated debate going on at my shooting club regarding the role that the rate of twist (bullet spin/rotation) plays in handgun "stopping" power.
Some members argue that the rate of twist is a major factor in the stopping power potential of a handgun.
According to them the high rotational speed of a handgun bullet (close to 50,000 rpm in the average 9mmP handgun with a 1/16 inch rate of twist) have a tremendous effect on a human body when hit by that bullet. One such member even entertained us by giving a demonstration with his portable power drill and a cup of water by plunging the spinning drill bit into the water - the splattering of the water was spectacular indeed !
The opposition argued that the rate of twist does not play any part in the stopping or hitting power of the average handgun bullet and have very little or no effect at all when hitting the human body. (they were not able to give us a demonstration to support their opinion !)
The leader of the opposition offered the following arguments to counter the arguments of the "pro-spinning bullet" faction:
1) The average depth of the human torso is about 12 inches deep. A bullet (from a gun with a 1/16 rate of twist) that passes through a human torso will only do about 1 complete rotation for every 16 inches it travels, which means that it will not even do 1 complete rotation in the distance it travels through the body - hardly likely to cause any spectacular effect or to contribute very much to the hitting/stopping power of that bullet?
2) The bullet spins at nearly 50,000 rotations per minute (833 per second). A bullet moving at 1100 f/s passing through a human body will not take one minute or one second to pass through the body: it is inside the body for less than a small fraction of a second? The bullet will only do a few full rotations in that fracture of a second - again hardly likely to cause any spectacular effect or to contribute very much to the hitting/stopping power of that bullet?
Not being an expert myself I would appreciate the views of the real terminal ballistic boffins on this topic with reference to any research done on the subject.
Kind regards.
Replies
I wish I could give you a qualified technical response.
Not a ballistics expert by any means.
Sounds like a argument much about nothing to me.
For me, it would be more about bullet construction and shot placement.
If folks spent more time under stress practicing with their handguns in realistic conditions from realistic stances then it would be much better time spent.
"The Un-Tactical"
I suggest that Mr. Drill guy tries this: spin that bit 3/4 of a circle in the glass of water and then spin it a whole 360 degrees. I am sure the difference will be negligible.
The purpose of rifling and it's rate of twist is to stabilize the projectile in flight...
At typical SD ranges, you could probably get similar terminal results with a smooth bore...
I can say Hi and welcome to the forum though. Hope you stick around, more the merrier.
I seriously doubt it. The fangs on these specialty bullets open up 360 degrees when the bullet performs to spec, therefore a little bit of a twirl isn't likely to increase the amount of stuff that gets cut/crushed/torn.
Kinda hard to test the theory though. . .short of shooting identical twins. . .
"Nothing is safe from stupid." - Zee
Jerry
:spittingcoffee:
- George Orwell
Welcome aboard.
When the demostrator puts the bit in the water and hits the juice, the bit is spinning without moving down into the water. Picture a boat with a high-performance propeller running at max RPMs, but still tied to the dock. It's going to kick up a LOT of turbulence behind the boat's transom since it's grabbing the water and pulling it back without forward motion. Cut the line to shore, and (eliminating the wake of the boat's hull for argument's sake) the propeller will, in a perfect, frictionless world, push itself forward through the water until the blades cut through the water cleanly with little disturbance.
Or another mental picture - a drill (or router bit) does its job best by moving its rotating cutting edges against the material, hogging out the hole by spinning without forward motion, or at least no motion other than allowed as the bit's nose allows by cutting its way into the wood. A screw, on the other hand, causes much less destruction to the wood by boring its way forward into the wood at the rate its threads bite into the material.
A bullet is closer to the screw in the analogy than the drill. The only practical purpose the spin imparts is to balance the bullet in flight, preserving accuracy and stability.
The guy with the drill and the cup of water is, quite literally, all wet on this one.
One in seven twist or one in thirty twist makes NO difference in the damage of the bullet.
WELCOME ABOARD!!!
Luis
Don't believe it for a second!
This has to be one of those things people see on Youtube and then extrapolate to some weird conclusion:
A more realistic view of bullet performance can be seen here:
I guess I'm suppose to believe I'll get better "stopping power" if I use a 1 in 12 twist instead of a 1 in 16?
Send your friends to this sight so we can discuss it.
How easy it is to make people believe a lie, and [how] hard it is to undo that work again! -- Mark Twain
Why, I thought bullets picked up velocity once they left the barrel, less resistance :conehead::tooth::guns::popcorn:
Words of wisdom from Big Chief: Flush twice, it's a long way to the Mess Hall
I'd rather have my sister work in a whorehouse than own another Taurus!
I seem to recall a gun-mag article years ago by Bob Milek or Skeeter Skelton where they unscrewed the barrel from a revolver and tested bullet performance straight out of the cylinder! The bullet simply passed through the threaded hole in the revolvers frame. They got remarkably similar performance with no barrel as to the same gun with its 2 or 3 inch barrel. I'm not talking about velocity or accuracy, but similar expansion in the test medium. It was at close enough range (nearly point blank) that the bullets hit nose first and then expanded as I recall. Does anybody else remember such a test? Or am I "disremembering" as George W. Bush would say?
No..you're spot in....I've even seen some vintage SSAs that had the barrels removed and were used as belly guns back in the day
I agree that out of short barrel handguns twist has little to do with stopping power, it does aid accuracy and prevent key holing or tumbling of bullets.
This is further proved by all the smooth-bore C&B / flintlock stuff we played with years ago.
On the other hand, if a bullet is marginally stable and maintains a nose first orientation until it reaches the target, only then to begin tumbling after penetrating, that might actually help incease damage in certain areas of the the body (in other areas it would work against you).
Of course, now we're talking about too slow of a twist! :roll2:
Not a characteristic that I would bet the farm on though.
JMHO
How easy it is to make people believe a lie, and [how] hard it is to undo that work again! -- Mark Twain
:bang:
How easy it is to make people believe a lie, and [how] hard it is to undo that work again! -- Mark Twain
In very simple terms, hydrostatic shock is like a splash. When you drop a rock in water, some of the displaced water splashes back up, in the direction the rock was traveling. Spin or not (smooth bore shotgun anyone?) it's a product of X mass times X velocity, and displaced fluid.
Bullet construction factors in only after the bullet has traveled far enough through the medium to do it's thing.
Sounds like the gun club guy is an undereducated blowhard. I'd tell him that if he's that concerned about stopping power, he should get a bigger gun. A .44 magnum, that can blow a man's head clean off, should do the trick.
Good memory. I am pretty sure that was Skeeter Skelton. I read that article in a compilation of either Skeeter Skelton or Elmer Keith.
Luis