layman's guide to bullet velocity, stopping power?

[cityartisan]

As of lately my firearms interest has taken me more to the ammo factor and more specifically, the physics involved. Trouble is I'm not that savvy with all the lingo I've seen on some of the charts for bullet velocity and was wondering if anyone out there might know of a reference for us "dummies" ("bullet velocity for dummies")
More specifically, looking for the amount of damage a particular bullet would incur with a given charge, i.e. , 357 rem. mag, FMJ to penetrate such and such an object, i.e. , (sealed tin can, solid wood 1-1/2" door, car windshield, 3/16" sheet metal at 50, 100, 300 ft.)
I'll continue my 'net research while you guys have a few laughs on this one, and BTW, no, I'm not fixin' to create a new target range- just lookin' to tune up the ol' noodle a bit
P.S. to save some of the headache, FPS= feet per second, MPS= meters per second, 1 grain= 64.789 milligrams= 0.0022857oz

 

[dennymac]

Energy increases with the square of the velocity. Simply put, a faster bullet hurts more than a slower bullet of the same weight. I can paint the inside of a 10 foot square room from 100 yards away using a V8 sized can of paint and a .22-250. Combine 55 grains of bullet with 3800 feet per second...You are shooting grenades. Penetration is largely dependent on the frontal area of the object doing the penetration. A brick dropped long side onto a piece of cardboard might not penetrate. But, do the same exact thing using the small end of the brick might equal penetration. Drop a full sheet of plywood flatly onto the surface of a lake and it will penetrate maybe 1-2 inches. Drop it edgewise and it goes under the water 8 feet or more. You can take a man down with a finger tip in his sternum, but the palm of your hand only shoves him back. Physics is very interesting. But remember, computers don't lie, but liars compute. Best of luck, and don't forget to have a good time.
DennyMac

 

[figley]

forget the term "stopping power". it's as legitimate as "assault weapon". it sounds to me like you're looking for information on terminal ballistics.

have you looked in the Box o' Truth yet? That's a good place to start.

 

[cityartisan]

Energy increases with the square of the velocity. Simply put, a faster bullet hurts more than a slower bullet of the same weight. I can paint the inside of a 10 foot square room from 100 yards away using a V8 sized can of paint and a .22-250. Combine 55 grains of bullet with 3800 feet per second...You are shooting grenades. Penetration is largely dependent on the frontal area of the object doing the penetration. A brick dropped long side onto a piece of cardboard might not penetrate. But, do the same exact thing using the small end of the brick might equal penetration. Drop a full sheet of plywood flatly onto the surface of a lake and it will penetrate maybe 1-2 inches. Drop it edgewise and it goes under the water 8 feet or more. You can take a man down with a finger tip in his sternum, but the palm of your hand only shoves him back. Physics is very interesting. But remember, computers don't lie, but liars compute. Best of luck, and don't forget to have a good time.
DennyMac

good comeback, DMac. Yeah, I did manage to put some time in and suck out some info from the cyberbrain. To sum it up, it seems to be one of those ongoing, scientific breakthrough hopefuls that continue to keep the physics professors employed! You know, "it was once believed that ___ but now we have new scientific data showing that......" Thanks to ballistic gelatin, and countless rounds of research ammo "the perfect cartridge" will be available to us no doubt. "stopping power" from what I could gather, is mostly used as an ammo sales term, with no real connection to physics. To paraphrase your answer if I may, the bigger and faster the bullet, the more damage will it do, given the material being relative(JHP,FMJ,JSP, etc.).
Anyhow, what I found concerning the question about penetrating random objects, there's a ton of vids on youtube w/guys test shooting through cars, trucks, watermelons, toothpaste and whatever, but not a whole lot of any evidence that any one caliber is better than the next(at least for self defense purposes), it's just a matter of personal preference, and how well you aim.
" But remember, computers don't lie, but liars compute" good one

 

[cityartisan]

forget the term "stopping power". it's as legitimate as "assault weapon". it sounds to me like you're looking for information on terminal ballistics.

have you looked in the Box o' Truth yet? That's a good place to start.

second what you said about SP. Checking out the B.O.T., looks really good! Thanks

 

[LarryC]

Sounds to me like you are chasing a rainbow! There are so many factors involved - as has been stated above, Terminal Velocity is really part of what you are looking for, however not anywhere near the answer. A 17 HMR has very high terminal velocity - but very little mass. A Weatherby .460 has fairly low velocity (500 gr @ 2600 ft/s) but extremely high mass and terminal energy at moderate ranges. The .338 Lapua has quite a bit less energy at the muzzle (about 4,900 lbf) verses the 50 BMG (about 13,000 ~ 14,800 lbf), but due to the .338 bullets ballistic coefficient after 1800 meters or so the .338 has more energy left, and holds the record for the longest sniper kill.

As far as the lethality of a bullet, this depends on the animal you are trying to dispatch (and the range you are shooting). A bullet that will kill a man at 300 yards with ease may not be lethal to a Rhino. Due to the fact that dangerous animals (Elephant's, Rhino's, Hippo's and the ilk) are hunted a short range, and must be "stopped" immediately rather than die later (after it has done in the shooter), many of the localities where these are found have restricted the bullets/guns used to a minimum diameter (AFIR, .400 dia). Therefore the powerful and lethal (to man) .338 Lapua is not allowed to be used. However if you wanted to shoot mountain sheep at 500 yard, the most powerful Elephant gun /caliber would be useless, as it would be like lobbing a bowling ball. Another issue is the ability of a bullet to penetrate obstacles, a 50 BMG will penetrate a 6~8 cement wall or 1/2 steel plate and kill anything behind it, while the .338 Lapua will not. A high velocity bullet 22-250, 17 HMR will be deflected by a thin branch, while a 45 ACP will cut through and deflect very little if any.

Another issue is bullet design - a Hollow point will expand rapidly and cause a much bigger wound cavity than a RN. But a round noise or FMJ will penetrate thick clothing, or thick skinned animals much better.

Soooo, to answer your question, it requires that (1) you specify the range you will be shooting, (2) Type of animal you intend to use it on, and (3) type of terrain you intend to hunt. It involves Muzzle Energy, Velocity, Mass, Coefficient of friction, Terminal velocity (determined by the previous) and Bullet design. --- Note: none of the things I have itemized involved ACCURACY, which if one of the primary considerations if you intend to do harm to something! :~)

 

[youngda9]

I came here thinking there was a new book or article out...then I realized the title of the thread said "layman's" and not "Lyman's"

Bummer, lol.

 

[BehindBlueI's]

There's no simple answer. Velocity, mass, sectional density, bullet makeup, bullet design, angle of impact, media of impact (fleshy vs bone, for example), and sheer dumb luck all play a role. Bullets can do weird things inside the human body, they deflect and divert more often than you'd think. The exact same bullet fired from the exact same gun hitting the exact same skull can have radically different effects depending on the angle and exact shot placement.

I can recommend the following book: Understanding Firearm Ballistics: Robert A. Rinker: 9780964559844: Amazon.com: Books

I used to own it, but it disappeared while I was overseas.

 

[AGarbers]

Terminal Ballistics
I find this site interesting and it cures insomnia.