Thread: Steel gongs

Originally Posted by BRADS

Of all the 50 cals and 375s I've shot my gongs with the worst was a 243ai with Barnes at around 3400

With typical steel targets it is velocity that kills steel.
Steel targets are typically specified based upon impact velocity and impact energy.

Impact velocities vs steel hardness
Mild steel is typically fine with an impact velocity up to ~1200fps.
~AR400 hardness steel is typically fine with impact velocities up to ~2500fps.
~AR500 hardness steel is typically fine with impact velocities up to 3200fps.
If the steel isn't hard enough then projectiles will pot mark the steel - this isn't good as it can lead to splash back, popover, and funny ricochets. This is why you see people say "steel is fine for the 338lap, but the 223rem and 55gr bullets cut it up".
One method of mitigating steel damage is to hang it on an angle. An impact angle of ~15-20 degrees helps a lot to minimise steel damage. Obviously most useful is to direct bullet impact into the ground directly below the target.

Impact energy vs Steel thickness
6mm steel is typically good for impact energies up to ~1500ft-lb (2030J).
10mm steel is typically good for impact energies up to ~3000ft-lb (4070J).
12.5mm steel is typically good for impact energies up to ~6000ft-lb (8130J).
Steel target will "dent" under higher impact energies - this isn't good from a ricochet point of view.

This guidance assumes the steel is hung and not rigidly mounted.