Physics Guys

[garym1a2]

It depends on twist rate and RPM of the boolit. Plus the fit,

[yovinny]

I'm not a physicist, just a dumb, uneducated city boy.
But if this is a hanging target on a pivot, your dealing with a cantilever, so exactly 'where' on the plate you hit it will change the length of your lever and make quite a difference.
Do both loads hit at the same exact POI ?

[wv109323]

Could you just add counterweight to the opposite side of the pivot point and fine tune the point at which the plate makes a 360 revolution?

[fouronesix]

No sweat. After 12 years of studying physics to the phd level, I would like to think I can explain it.

I figured there was some background reflected in the response. Momentum is intuitive by nature while kinetic energy is not. Confusion usually surrounds the application or understanding of both concepts- especially when discussing ballistics in threads like this one.

[DrCaveman]

Try water dropping your boolits (if you aren't already) and leave everything else the same

[44man]

Boolit weight and more velocity! The heavy steel feels no more then the little .38 feels in your hand.
The .357 at IHMSA shoots would not take all the steel so they came out with the max that could shoot 200 gr bullets at near 1800 fps with a momentum of .97. The 158 in the .357 mag only had .64. The .38 is most likely in the .4 range. The .44 could be borderline with a figure of 1.03.
Hang time of a bullet on steel can apply more momentum but nothing matches weight or velocity.

[mwc]

Could you just add counterweight to the opposite side of the pivot point and fine tune the point at which the plate makes a 360 revolution?

Check out the mgmtargets web page and look at the gravity moving targets, if you click on the single spinner there is a video of what target I'm talking about.

[mwc]

Try water dropping your boolits (if you aren't already) and leave everything else the same

Where I'm PCing my boolits and baking the pc that will negate any water quenching effects.

[mwc]

mwc - try adding some copper via CuSO4 method on your soft alloy. Or you can use sulfur but it is messier. Definitely will let the boolit hang together longer. Both are cheap and easy.

I have ordered some of the 7% cu babbit from roto metals, that I will alloy into some of the alloy I have. I may try to use the CuSo4 method also, but from what I understand, the sulfate takes on the tin first then any zinc. Since I don't have zinc in my mix won't this take out the tin and replace with copper, then I would have to add some more tin back to the mix. If I just use pure lead and throw in some zinc, then sulfate to add copper then tin and some antimony. I think that your right if I make the boolit tuffer should also give the same results as will making the mix harder to achieve similar results.

[mwc]

Boolit weight and more velocity! The heavy steel feels no more then the little .38 feels in your hand.
The .357 at IHMSA shoots would not take all the steel so they came out with the max that could shoot 200 gr bullets at near 1800 fps with a momentum of .97. The 158 in the .357 mag only had .64. The .38 is most likely in the .4 range. The .44 could be borderline with a figure of 1.03.
Hang time of a bullet on steel can apply more momentum but nothing matches weight or velocity.

A lot of this whole issue is based on my ability and consistance at shooting and hitting the target at the right time, I have been able to spin the target with just 5 shots using my MD625, 45acp using 230 RN. I have been able to do the same thing with 10 shots from my 9mm using 130 RN. So far with 16 good hits I haven't been able to spin it with my 38 spcl. check the video out on mgmtargets site under gravity moving, or under skillbuilders targets. It's fun but frustrating.

[olafhardt]

The problem with applying physics to this situation is that it is not an elastic collision. Deformation of metal requires energy which is converted into heat which is why the plates warm up. The energy is conserved and so is the momentum. This can all be worked out mathematically which is complicated and will be different for each boolit. Since the harder, tougher bullets usually have more elastic collisions they should theoretically swing plates higher. This is more easily studied with a gun and boolits and a reloading manual than a calculator, pencil and physics book.

[Ballistics in Scotland]

What caliber, bullet weight and velocity and the weight of the pendulum?
And why the complete,Revolution? Just for the wow factor?

I can see what the OP is getting at. If a bullet entered a massive wooden pendulum and got stopped without disintegration, all of its energy (except for some heating of the wood fibres) would be transformed into forward momentum in the block. If the bullet disintegrates and some of the fragments are hurled sideways, some of that energy isn't transformed into forward momentum. The same would apply if you fired a hard steel ball bearing, which bounces. What the bearing still has, the pendulum doesn't.I

It seems entirely logical that different bullet hardnesses may do that to a different degree, although I suspect that the difference is negligible. You could determine it like Robins in the 18th century by using a heavy pendulum which draws a tape, nylon monofilament or cord through a loose eyelet as it moves, but doesn't feed it back though as it returns to the vertical. The bullet which pulls though the greatest length of tape has imparted the most momentum to the pendulum.

In answer to your signature, mass is a measure of how much matter is in an object, and weight is a measure of how much the earth's gravity pulls on it. If some cataclysm of nature had caused the human race to evolve exclusively on mountain tops, the kilogramme would be very slightly less. If you take a cannon-ball of the 68lb. size into space, it will hover in mid-air like a soap-bubble, because no planet attracts it, and it has no weight. Kick it and you will damage your toe as much as anywhere else, since if no iron has been removed, its mass is the same as ever.

[Taylor]

Makes me wish I had finished 3rd grade.

[44man]

Friend bought me a .22 swinger. No bullet on earth will swing it. Maybe my .44 will make it loop.

[DrCaveman]

Where I'm PCing my boolits and baking the pc that will negate any water quenching effects.

Ok, mr difficult (kidding)

Add more powder, as suggested by many. Or use your harder alloy, as suggested by many. You cant defy physical reality, and you are looking it in the face

[rsrocket1]

This isn't so much a Physics problem as it is a testing problem. If you simply worked up a load with your favorite cheap bullet to where it swings any target regardless of where you hit it, add a bit more powder to account for variations in drop as well for mushiness in your grip vs benchrest (or not), you will be able to swing a target with that load no matter where you hit it. Don't waste your time trying to theorize and experiment. That is, unless you are getting enjoyment from that too which is OK if that's what floats your boat.

[Wayne Smith]

Some of us are just plain curious. I found out 'what' but I want to know "why"!

[44man]

Want to see steel fly, use a 440 gr from a .500! It is a hoot.

[BenW]

Hardness makes no difference in how much momentum is transfferred to the plate, unless the bullet ricochets. Momentum is conserved in every direction through all events, no matter how long the event is. The only way to get the plate to move back more is for the bullet to reverse direction (ricochet). That's why your fmj ammo is enough, but the lead isn't.

[Certaindeaf]