M855A1 variants

Is there a good document on the M855A1 stuff?

Kevin pointed out the following:
1st tin/bismuth base, steel tip, copper jacket
2nd copper base/jacket, steel tip
3rd solid steel 1pc core, copper jacket (is there a way to ID this? Magnet I guess?)

"Early Experimental tin/ bismuth core, copper core, Solid Steel core (Looking for info), and several malfunctions. "


Never did get an answer on the solid steel M855A1.
Have included a picture of the other M855 test rounds mentioned in the article, the tungsten tin and tungsten nylon. Pepper had these on his table one year and you couldn’t tell the boxes apart, and once pulled, the rounds are undistinguishable. (All looked the same)

The second picture is the another from Oak Ridge, Tenn. from a company called Powell River Labs. Its another M855 made with powdered copper.