megcatia, what are the plates made out of? They appear to be stainless. Anything less than 3/8 inch hardened plate (ar400 or ar500) may not last very long.(see BigBlueEyedDevils post above)
My experiances with target steel.
Mild Steel. 1/4" through 1" OK for rimfire targets,
Centerfire blows through it like a drill.
T1 Steel 3/8" Great for Rimfire Targets, 22RF does not make a mark.
Centerfire goes through it so fast at 175 yards that it
doesn't even swing.
AR400 5/8" and 7/8" This is REALLY good stuff. 300 WBY knocks
the paint off and makes a very small crater at 175 yards.
Beleive it or not, at 175 yards, a .17 Rem does more damage
than the 300 WBY. At 25 yards(minimun CF rifle distance) .223
FMJ makes a very small crater.
AR500 3/8" for swinging targets and 5/8" or thicker for static targets.
I could not find any of this locally, but my research tells me
THIS IS THE STUFF
I made mine using the "modular concept" Anything that can/will inadvertantly get shot can be easily replaced. Any areas that are very likely to get shot should be "faced" with hardened plate. I made my plates with holes in them for bolts. The bolts allow me to easily replace the support chains/arms when needed.
Give us a range report and let us know how it hold up and don't forget the pics.
Darkside