I am wanting to buy some steel targets for use at CJ on the rifle ranges, in the spring. I use the Greek M2 ball for the M1, and some of the ammo for the SKS is steel core, or bimetallic, whatever that means. I would use these at 100 yd minimum, 50 yd for .22. So what thickness plate should I get for use with that type of ammo, or is that not advisable due to wrecking the plate or possible fragmentation?