Steel Target Selection for Sniper's Hide
by ptm121
If you shop for steel targets, you'll see all kinds of generalizations about what calibers are good for what ratings and thicknesses of steel. Using
those charts is the equivalent of holding your duplex reticle 18" over the target to try and score a hit. This is The Hide, and we are smarter than that!
Everyone here should be able to calculate velocity and energy remaining at any given distance for their particular bullet. Once you can do that, all the guesswork is gone from target selection!
Target hardness, achieved through heat treating, is given by the AR rating. There are TONS of steel alloys and treatments, but the only three that you normally run into for targets: mild steel, AR400, and AR500. These come in thicknesses from 3/16" to 1".
Bullets damage targets in two ways. When the bullet strikes, it splatters itself out, and this process turns a lot of kinetic energy
(KE) into heat. This heat and fast moving material can cut the target surface, like a torch. If the steel is harder, it will resist
this cutting better. The heat generated is directly related to velocity, so a .223 Rem with a 40gr bullet at 3,700 fps will actually
do more damage to a 1" AR500 target than a 300 Win Mag (210gr bullet at 2900fps), by putting small craters in the surface.
These pits will grow and eventually act as half pipes to shoot lead and copper back at you.
The other method of damage is a bowing or denting. This is from the mass of the bullet deforming the target backwards, away
from the impact, just like hitting it with a hammer. AR steel is a little more resistant to this, but thickness is the dominant
factor by far. There's a very strong correlation between impact energy and the bending or denting damage the plate will see.
So, as I said: pull up your ballistic app, and run the velocity and energy numbers at the ranges of interest to you. Then pick
your targets based on these ranges:
First, select hardness based on velocity:
<1200 fps: mild steel is fine.
1200-2500 fps: AR400
2500-3000 fps: AR500 (might get pitting with FMJ at 3k fps)
AR550 buys slightly more velocity, and can be a good idea for 5.56 at closer ranges (3000-3200 fps), but is really past the point of diminishing returns for most uses.
Then, select thickness based on energy:
<500 ft-lb: 3/16"
500-1500 ft-lb: 1/4"
1500-3000 ft-lb: 3/8"
3000-6000 ft-lb: 1/2"
6000-8000 ft-lb: 3/4"
8000-10,000 ft-lb: 1"
For long range shooters, two things become apparent quickly: AR400 steel is normally just fine, because we rarely have velocities over 2500 fps at extended ranges. Also, at ELR, even really heavy-hitting rounds can take a pretty light piece of steel. Lighter steel not only saves money, is easier to hang (and haul to temporary ranges), but also rings louder. Hearing impacts at
1200 yd with a 6.5 can be tough! 1/4" steel is plenty thick for just about any .30 cal magnum at 1,000 yd, and can even take .338 LM hits at 1500 yd or so.
As usual, caveat emptor. Hang your targets with a little forward lean to deflect the bullets at an angle, and hang them so they can move when struck. This information is only valid for lead and copper projectiles. Solid brass or copper, or even thick-jacketed FMJ rounds are harder on targets. So are very long bullets - that cutting-torch action is prolonged when a 90gr VLD hammers into a target, vs a 40gr varmint bullet. Steel-cored or steel-jacketed bullets are NOT to be fired at steel targets, without substantial extra range margin! So, if you are on the hairy edge of the tables above, consider other factors like bullet type, volume of shooting, and if your buddy with a .243 WSSM or .338 LM might end up using the range some day.
