Velocity vs frag on steel question

[Mr Spooky]

Anyone know if there is a difference in the amount or distance of frag after hitting steel plates with different velocity bullets? Would a 147gr 9mm produce less frag and would the frag travel less distance vs 115gr ? Would the frag be traveling slower since the initial velocity is slower. Or since there is more metal jacket on the heavier 124 and 147gr it's going to produce even more fragments?

[Danimal]

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[Bmac]

How's the new place?

Is that a 3% lama!!?

[Mr Spooky]

Sure is. Llamas make badass guards. They are mean! Its a custom patch I had made up for a little "shooting survival club group thingy"

[Great-Kazoo]

Sure is. Llamas make badass guards. They are mean! Its a custom patch I had made up.

They also have excellent eye sight.

[C Ward]

Sprag coming back from steel is a function of how its set up , quality and condition , and blind luck . Everybody I've shot with has been hit with pistol sprag .

Set the plates up with some give so they move when shot , angle them to send the bullets in to the ground , and get rid of them when they become cratered . On pistol steel no closer than 10 yards and 150 for rifle is a good rule of thumb . You can get away with mild steel with pistol and shot in a shotgun but rifle and slugs use AR500 .

If you shoot steel long enough with pistol you will catch some sprag , I've got hit with 9 , 40 , 44 , and 45's and know people that have caught rifle and pistol sprag . The bullet doesn't always behave predictably wear your glasses .

[Not_A_Llama]

Faster produces more and faster frag. But the pieces are smaller. Figure your tradeoff as 1/2mv^2, and counterbalance against momentum being mv.

Check out the Kurzzeit videos.

I can definitively suggest that you always want eyepro when shooting steel, and that I haven't caught any interesting frag shooting pistol against AR550 to about 4m, and M193 and 7N6 to about 5m. Closer than that gets scary. Shotgun slugs form cool little mostly-intact Hershey Kisses that come to rest about a foot in front of the target.

[MarkCO]

Mostly correct answers. The slower the velocity and the "tougher" the bullet, the higher the chance of fragments coming back towards the shooter...all else being equal. Hard, flat steel with angle and or give is best as Chuck said.

However, you are safer shooting a .223 at steel from 10 yards than a pistol, which is safer than a slug. The reason we have rifle steel at 100 yards and beyond and limit the velocity it purely to make the steel last longer.

So, a 147 going 900 fps is more likely to have a fragment come back towards a shooter than a 115 going 1150...again all else equal.

[C Ward]

Been shooting steel targets for 20 years now and there is no way in hell I'm shooting center fire rifle closer than 100 yards without frangible ammo . Just because 99 out of 100 you get away with it doesn't mean that 1 time won't bite you in the ass , especially with the Russian 5.45 with bimetal jackets .

I'll introduce you to the guy I now that caught a piece of 30-30 from 50ish yards the went to the ER to get his arm sewed up . It's just not worth it shooting a rifle at steel that close , besides the damage being done to the targets by what amount to muzzle velocity impacts .

[MarkCO]

Been shooting steel targets for 20 years now and there is no way in hell I'm shooting center fire rifle closer than 100 yards without frangible ammo . Just because 99 out of 100 you get away with it doesn't mean that 1 time won't bite you in the ass , especially with the Russian 5.45 with bimetal jackets .

I'll introduce you to the guy I now that caught a piece of 30-30 from 50ish yards the went to the ER to get his arm sewed up . It's just not worth it shooting a rifle at steel that close , besides the damage being done to the targets by what amount to muzzle velocity impacts .

I did not say a .30-30 Chuck, I said a .223. And it has been tested and proven many times. I have been shooting steel, and testing steel bullet interaction professionally, for 20 years, including government and private contracts. Yes, it will damage the targets. Point is that people tend to think backwards when it comes to understanding steel bullet interaction w.r.t. mass and velocity. A slower projectile poses a greater risk of a bullet coming back along the path it took to the target than a faster one in most conditions.

[C Ward]

Not so much you Mark , but I've stopped counting the people that got razor bladed by a piece of jacket coming back off of properly set targets to know that shooting pistol and rifle at steel at 4 yards is just silly and asking for a ride in the ambulance . Ask Eric about the chunk of jacket Trapr dug out of his head last year .

[MarkCO]

Not so much you Mark , but I've stopped counting the people that got razor bladed by a piece of jacket coming back off of properly set targets to know that shooting pistol and rifle at steel at 4 yards is just silly and asking for a ride in the ambulance . Ask Eric about the chunk of jacket Trapr dug out of his head last year .

Unless you know exactly what you are doing, yes you are right. I think Eric was born with metal in his head. :)

I really don't like pistol inside 10 yards and slugs on steel...at least 50.

[Erni]

Mark,
I've always been fascinated with the bounce vs splatter vs penetrate that can occur with projectiles. Can you point me towards any more info to geek out on?

[Irving]

Mark,
I've always been fascinated with the bounce vs splatter vs penetrate that can occur with projectiles. Can you point me towards any more info to geek out on?

You can start here.

QfDoQwIAaXg

EDIT: Mini14 at 5:06!

[MarkCO]

There are a few books on ballistics you can buy on Amazon that have some material strength vs. impact energy charts, but many of them are taken from US Military tests and their treatment is sometimes inaccurate. High speed impact tests related to material shear, molecular shear, etc. are in various texts and handbooks. Even combining Machinery Handbook's material strength data with the known levels required for metal disintegration by electrical means will give you valuable information. Metal Disintegration machines basically vaporize metal to remove it in several manufacturing applications. The papers written on the required levels can be converted into mechanical approximations, then you have impact velocities based on measured grain size of the lead and the material properties of the specific alloy.

I did a lot of this type of work creating models for shooting reconstructions many years ago. I used it to define a range of distance from which a bullet was fired based on material penetration, shear and deformation, including human tissue. The bullet geometry and material properties were important. If you know which variables to hold, material interaction is very predictable. As far as I know, i was the first Forensic engineer to use these methods in an actual court case. Virtual autopsy is gaining in popularity among coroners and uses CT and MRI images to create a 3D model. But, cool thing is, we can do this with living persons who have been shot, harvested game animals and even constructed items. The Army Corp of Engineers and USArmy Materiel Command have some declassified papers and reports you can read that have bullet ricochet analysis and some velocity levels for disintegration v. shear/rupture v. deformation v. deflection.

[Mr Spooky]

Was shooting steel this sat the same way we have been for years and my buddy took some frag just above his belt to the left of the belly button. It was a bleeder, went about 1" deep. Busted out the ifak and off to the ER. After x-ray they pulled 2 nice sized jacket frag pieces out. Was shootng 115gr 9mm at 6" knock down plates (brand new, first run with them) at about 15yds. I happen to be recording his run and after watching the video frame by frame it was just one of those unlucky hits. The bullet hit the lower corner of the plate and the frag used the horizontal base as a slide right back at him. He usually gears up, but this time he went "gray man." His vest would have stopped it. I modified the stand by adding a lip, so now the lip should catch most of the frag.

Here is the set up we were running, the knock down plates are at about belt level, I am kneeling down in this pic:
http://img.photobucket.com/albums/v95/556FMJ/image.jpg1_zpsskhwlr86.jpg

Guess this is a reminder to always shoot safe, and be prepared because there are those rare accidents.

[MarkCO]

Yeah, and makes me think of the lady this past weekend who refused to put glasses on her 4 year old because he was "far enough from the gun".

If you do not have a flat surface (bases and shepherds hooks and bolts are not flat) then you increase your risk of a come backer. Not a "rare accident" with that type of plate, just not something you had seen before.

[Danimal]

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