This is the first I've heard of your steel... Good stuff huh!! I like shooting steel better than anything else. Immediate reply and feedback, see the strike and can make correction. Better I believe for wind doping and education...
We've on ocassion shot through 500 Brinnel 3/8th inch with rounds going over 3100 fps. 338 Lapua with 200 Noslers at ~ 3350 and a 300 Win mag with 165's at ~ 3250 fps.. (patch the hole with a bolt).
That "splatter" is a problem and it travels a long(ish) distance. I was "observing" a mover system for functionality problems from about 50 to 60 yards off to the side... bad idea!!! The shooters were 600 yards distant but the splatter from 308's was enough to cause bleeding when struck (through bluejeans).
Steel...(hardened steel AR 500) Paint it light color and fire a round to center mass... big dark "splat" on impact... thereafter you can aim at that.
I also use 8.5" x 10" plain paper and print a circle on it, white center on a large black circle.
Find a used (it'll be used after the first round anyway) piece of 4' x 8' plywood. Cover it with butcher paper and put your "printed" target in the appropriate place (top, bottom or middle depending on your desires) and shoot. You can plot POA to POI for "long" distance shooting and come-up data. You can make a set of data charts in one pass with the plywood target(s). Put the target at the top and select a range... shoot a little group, back up a hundred yards and shoot another, etc, etc. Walk to the target at the end and measure the "drop" divide by distance and make a come-up chart. (Verify once so you know your math was correct and you're set.)
I asked this question at the earlier part of the year and got a few creative answers. As a result I confiscated the kids old tublar swingset frame, shortened it one top pole so it is 6 feet across the top and I plan to hang things like bowling pins with an eyebolt screwed in the top or a 3/4" thick plate of T1 steel that the colledge machine shop class turned down to have an outside diameter of 11.5" (or 1 moa at 1100 yds).
We can also hang a short sheet of plywood from it or lean a full length sheet of plywood against it and secure it with wire ties.
We assemble the thing quickly with cross pins instead of bolts and if we shoot a hole in it then big deal. We can get another one fairly easily. I would go to the stores where they sell the big wooden play sets and have the sales people keep an eye out for parents up-grading to a new playset. Have them tell the customers that you will be glad to haul of the old tubular swing set.
Legaly obtained realty sign hangers (the kind that press in the ground that hold a 18x24"sign) are also cool for the shorter range work. Dont steal them out of other peoples yards though.
GRAVITY. It's not just a good idea. It's the LAW!
I don't think we talked since I got my target steel purchased and set up. It is T-520 hardness and bullets don't even dimple it. Example would be 176 grain Cauterucio at 3,150 fps muzzle velocity with terminal velocity of 2,400 at 600 yards and 2,000 at 1,000 yards.
I painted the 2 ft by 4 ft piece of steel with beige paint. I made a spraypainting target template out of cardboard to use in painting a 5 inch outlined square (1/4 inch thin lines)at center-mass. I leave spray cans with the 2 colors down below and behind the target frame for touchup. At first I was casual about where on the ground I left the cans. Until one day while shooting I wondered what that puff of "smoke" was all about. Now I am sure to keep the cans just behind the steel so shrapnel doesn't splat downward and pierce the cans.
With my Nightforce 5.5 to 22 scope I can see the bullet splats on the steel at 1K.
MCM is a company that makes shooting products out of formed plastic. I have been using their portable target frame lately when traveling. It consists of a rigid plastic base with steel spikes to push into the ground and a horizontal holder or frame. Into the holder you insert their corrugated plastic target-backer-sheet. Before I leave home I tape or staple a 2 foot square cardstock paper target to the target-backer. I have used this system out to 1200 yards in New Mexico and 400 yards in Colorado.
It easily breaks down for storage during travel in the bottom of my big duffle bag. The target-backer sheet folds in half. I got it for travel but last month found myself using it at home to check my rifle at 715 yards from one of my tall 24 foot stands. I am sure you could easily make something but it was quite cheap anyway.