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-   -   High Speed vs lower speed cartridges. (http://www.firearmstalk.com/forums/f18/high-speed-vs-lower-speed-cartridges-78153/)

Colby 12-10-2012 12:08 PM

High Speed vs lower speed cartridges.
 
I have recently come upon some comments about the much greater destructiveness of higher speed rounds versus the lower speed sounds - against hard inanimate objects. Against flesh - well known. But against objects.
Does anyone have any good experience with this - any guidelines as to what you should or shouldn't be shooting at - depending on how you do or don't want to tear up a certain target.
The comments were concerning favorite set up steel plate targets that were normally used for all kinds of different cartridges - mostly pistols (but some pretty big pistols in the mix) and some rifles. The high speed high power rounds were not used against some favorite steel targets - for fear of severely damaging them - and wanting them functionable later for other demonstrations.
Any thoughts on this.
I'm just not that knowledgeable... But I'd like to understand.

locutus 12-10-2012 02:57 PM

High velocity increases kinetic energy by the square of the velocity.

For that reason, the M-1 Abrams tank uses a smooth bore main gun with a velocity of ~ 5000 FPS. The non exploding depleted uranium sabot round is the most destructive ever used by a tank.

High explosive rounds are available for that gun, but the sabot round is the round of choice against armor.

SSGN_Doc 12-10-2012 03:13 PM

Alot can depend on bullet construction as well. Thin jackets and light weight bullets may not do as much damage against harder objects.

If you are talking about shooting steel plates specifically and not wanting them torn up, then it would depend on the metal used and any hardening treatment to the metal. Most target manufacturers will rate their targets for certain types of rounds. AR 500 Brinell steel is rated against heavy rifle rounds for thousands of hits. Most handgun rated targets have half the hardness rating and can be damaged by rifle rounds.

MGM Targets has a lot of good info on their site about steel targets, as well as a good selection of targets.

MoreAltitude 12-10-2012 03:31 PM

I've posted this video before, but it is simply amazing. 1 million frames per second of rounds onto steel plate, plus other stuff. Hardened steel plate and softer steel targets. Doesn't really answer your question, but interesting to watch given the OP's choice of subject...


YouTube: 1 million fps Slow Motion video of bullet impacts made by Werner Mehl

http://youtu.be/QfDoQwIAaXg

oldpapps 12-10-2012 03:46 PM

2 Attachment(s)
41 years ago last summer a co-worker and I got the bright idea of making up some reusable targets out of 3/8 inch boiler plate.
We shot these targets with a wide selection of weapons and loads.

Soft lead splatters. Hard jacketed bullets bounce back. Very hard FMJ (military stuff) cuts a chunk of the metal out and throws is back at ya. It's very hot!
Didn't matter if it was pistol stuff or surplus rifle stuff. Just bigger chunks.

Going to shoot metal? Make sure the target metal is thick and at a longer distance.

Now, I have my target stand set in front of a rock out cropping at a hundred yards. I still get some pistol round coming back from my 25 yard tree stumps.

The upper photo is .45 ACP 230 FMJ/what was shot, into a steel tank and into a tree stump. The lower is (.40 S&W) into and back from a (new) cedar tree stump. Don't ask me to explain the 40 cal. That is lead and it came back 25 yards!

http://www.firearmstalk.com/forums/attachment.php?attachmentid=73975&stc=1&d=13551572 50

http://www.firearmstalk.com/forums/attachment.php?attachmentid=73976&stc=1&d=13551574 06

SSGN_Doc 12-10-2012 08:13 PM

If using fixed steel plates it is also advised that the plates be angled leaning forward at an angle so that any spall is bounced toward the ground, and not directly back at the shooter. This also means that the area that the target is standing in should be free of rocks so that no other fragments are ricochetted back toward the shooter.

John_Deer 12-11-2012 01:40 AM

Fixed plates are a bad idea for any round. I don't know the science behind it. But I have seen to many bad outcomes from people shooting fixed, immovable steel objects. If you are going to acquire silhouettes or any other steel target make sure they swing, fall or have some type of motion when a bullet strikes them. Swinging targets have given me the best results.

HockaLouis 12-11-2012 01:56 AM

Colby, energy translates into velocity, not the other way around as has been indicated above. If you put more energy into one of two otherwise identical bullets, i.e. burning more and/or faster powder behind it, it goes faster and has more energy!

Powerful hard bullets hurt "soft" targets. Greater than 40 degrees from the perpendicular will redirect the bullet with almost all of its energy. A hard bullet can cause concavities, also known as "flats" in a plate and it is there, where a bullet hits a spot less than 40 degrees that a backwards rebounding ricochet is coming after you. Ever shoot Practical Pistol? Did they ban you from using jacketed ammo!? See...

Look at accuracy too. .22 caliber and smaller, as a rule of thumb, tend to be more accurate the faster they go. It is the opposite for larger.

locutus 12-11-2012 02:50 AM

The velocity of the bullet is indeed determined by the release of energy from the burning powder.

The kinetic energy the bullet carries is a function of velocity.

nitestalker 12-11-2012 03:01 AM

If you want to see amazing damage to steel targets hard or soft. Fire a .220 Swift with a 50 grs. bullet running 3,800 FPS. in to a metal plate.:eek:


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