Home Forums Hunting & Shooting Ask The Gunwriters Mule Deer -- .30-06 and .300 H&H

"My point was simply that if you use the same bullet, place it in the same spot, and shoot a lot of animals and average out the results, there is little to no difference because once an animal falls to the shot, how can you claim additional killing power?"

AGW, this is yours, minor point but you did define "killing power" here.

"how can you claim additional killing power". I do claim it by my definition. My point is that I think your point was lost on some. Maybe because we're hung on on physics, mags do have more horse power.

BobinNH, Thanks, I honestly do want to know more about the subject. Right now I'm thinking there's not a lot of energy in the rotation. Kind of like the energy in trailing gas someone else pointed out.

I agree with your point.

The repetition of the phrase "killing power" was used against my comment, not used by me in favor, of it. My opinion is as yet, an unchallenged statement, as no animal has been nominated.

AGW

Gmack: I don't think it's an energy issue at all; I just think it's a mechanical thing. I'm no engineer, so can't explain it. But we know rotational velocity plays some part in bullet expansion. Take a look at the 165 TSX over on the Africa thread that was recovered from an Eland. The petals are twisted out at an angle to the shank of the bullet. What causes that? I think it's a combo of velocity and twist.

I was reminded this afternoon that John Jobson wrote of using both a 10" twist and a 12" twist in a pair of 270's. Noticed the 10 twist was a more dramatic killer than the 12 twist. I remember reading that myself.

HUSQVARNA: Dated info? Something happen to bullet flight and physics, terminal balistics since the 1970's? Got news for ya; TSX bullets are not "new"; PO Ackley invented them in ,I think, the 50's; WSM's are not "new", they were invented by a California gunsmith in the 50's. Contolled expansion bullets and Northforks are not "new". Bill Steigers (Bitterroot Bullets) had that scene going on in the 60's.

I'd like to know, after you read the article, exactly how what happens when a bullet is spun out of a rifle barrel and impacts an elk, is different or dated as opposed to what happens today? Elk DNA has morphed into a denser medium immune to ballistic laws existing prior to Y2K, or what?................

Good point...........

jwp: Whad I say??...........................

Hey Bob , I was just going to post
on old Jobson's observation of 1 in 10 versus 1 in 12 270 s .

I tend to think there is something to high rpm thing myself , , seems to me there's a trend there with such calibers as the 264 , 7 mag , 270 and 06 with 150 gr bullets.....

SD: Course ya know our info is sort of dated............ ...After all, what did Jobson know? He was a rifleman fron the 60's and 70's!Even tho he shot a lot of game and a lot of rifles!

I think there is something to it all.Be nice to see someone research it

+2

Terminal Twaddle...

The energy issue - it takes energy to spin something. look at how much slower a curve ball is. A pitcher who has a fast ball of 90 might throw a 70 mph curve?

If my quick math is right, the rpm does look outrageously high by machine design standards. Going from 12 to 10 twist looks like 20% more rpm.

Still thinking on this one, how rotation fits into the big picture. I thought I read one writer noting that his load speeds didn't drop much when he fast twisted a barrel. If that is true there's not much energy difference. It takes the energy that would go into straight line fps to spin something faster.

Not saying anyone's wrong. Talk about hi-jacking a thread. I am a non-practicing mechanical engineer. My career took me into construction, boy does that have a dumb down effect. Maybe that's my problem.

A riddle:

At what point do the laws of physics no longer mean anything?

AD

So if a mushroom rotates once while penetrating 10" of meat at 3000 fps it is more lethal than the rotation in 12"?
I would like to see that subject study.

Stray Dog: Quit ragging BS; I told you where the damn article was; just go read it! I'm not here to waste my time arguing with anyone;if you feel as if you know more about it than a ballistician from the SPEER BULLET COMPANY, then do a treatise on it yourself after you have researched the issue.What, precisely, is so tough to understand, anyway? Just read the article if you can find it. I'm sure someone on here can get it for you.You want the study, THERE IT IS!

You drive the bullet faster,it revolves faster, places greater stress on the jacket and it opens more violently on impact.Is it more "lethal"? I don't know. But if bullet expansion means nothing, then just shoot solids; why not do that? It's "lethal".

My my what a run away, I didn't ask you all of that chit.

Someone may be having a ragging moment.

Answer:

When you are dreaming.


The energy from any bullet starts out as chemical energy from the powder. Then there is always a loss due to efficiency but the bullet leaves with rotational and projectile energy in kenetic form.

I believe there would be a balance if the powder charge remained the same. If you go to a faster twist more energy goes to turning the mass and less can be available for travel.

Never thought much about the rotational energy before because I took it to be insignificant. There is no question however that a higher RPM bullet would stress the bullet jacket more. Whether this would aid expansion in any appreciable amount...?

Several articles have been published in the last decade that indicate from test that bullet spin has little or no effect upon the bullets behavior on impact. The only one I can site offhand is Gary Sciuchetti's "The Best Hunting Bullet" HANDLOADER #193 June 1998 pp.40-44.

It could be a great deal about very little, or very little about a great deal.
If an O6 bullet spinning at a faster rate could cause more damage than a 300 mag spinning at a slower rate, this would be news to share.

But it is most likely some form of Terminal Twaddle...

Curveballs aren't slower because putting additional spin on the ball consumes that much more energy. Curveballs are slower for at least 3 reasons I can think of. One, the human elbow just isn't designed for throwing overhand, and the additional stresses on the ligaments and tendons caused by snapping the wrist diagonally rather than longitudinally are pretty bad. In fact they keep a lot of orthopaedic surgeons well fed. Two, the curveball works not only because of its movement, but because of its slower speed than the fastball; same function as a changeup, with the added benefit of movement. Throws the hitter's timing off. Lastly, the path a curveball takes is dependent not only on the side forces caused by the spin (see http://en.wikipedia.org/wiki/Magnus_effect) but on the ball's initial velocity. If the ball is travelling too fast, there won't be that much lateral or downward movement; the best curveball pitchers can adjust not only spin rate but velocity to dial in the desired amount of ball movement. You've no doubt heard sportscasters talk about a "breaking curveball". I had the opportunity once to stand right behind a catcher who was warming up a MLB reliever during spring training. The "break" was very visible, I believe due to the ball slowing down to a speed where the flow around the ball transitioned to mostly laminar flow and thus gaining much more Magnus effect. Add 10 or 15 mph and I don't believe there would have been any substantive movement before the ball crossed the plate. But this guy was able to locate the break about 10 feet from the plate, consistently.

Now some pitchers can throw sliders, tailing fastballs etc at nearly the same speeds as their fastball, but those pitches don't have nearly as much total lateral movement as a big curveball.

I dunno, I just aim and shoot.