Yea Charlie, further research found that they foul bores badly.
Stuff I saw was German made (maybe French) presumably in the 90's and inexpensive.
With the price as it was I figured there was some catch to it.
In the early days of the 1903 Springfield, the army issued cupronickel jacketed bullets. They had a reputation for fouling and the army had a solution using strong amonia to clean it out. A barrel was plugged and then the amonia solution was poured in and let stand for an hour or so. When poured out, the amonia solution apparently took the cupronickel fouling with it. There were reports of totally ruined bores now and then from the process though. I think that resulted from 02 getting past the plugs (my memory is vague here).
At Camp Perry in the early years, marksmen using the cupronickel bullets would lightly greese each bullet before chambering it and firing. This was an accepted practice until rifles started blowing up and the procedure was abandoned about the time gilding metal jackets became available.
Druggist's amonia solutions over 27% or so can be very caustic to metal and obviously the army's old procedure can't be recommended today.
Info above came from either Hatcher's Notebook or perhaps Brophy's or McBride's books on the Springfield and its use in WWI and the range.
Outers used to make a product called "Foul Out." It used an unknown (to me anyway) solution along with an electrical current from a battery unit and a negatively charged steel rod down the barrel to de-plate the fouling in a bore. The metal fowling would then plate the rod where it could be wiped off after use. It was just the opposite of nickel plating a firearm. I never used it, but friends said it worked well.
Speaking of cupronickel bullets, my first high power rifle was a No 1 Mk III Enfield. Surplus Mk 7 303 ammo was cheap but much of it was cupronickel jacketed and once it started fouling it took several brass brushes and a lot of elbow grease to get it all out.
Several years ago, I broke down a couple of thousand or so rounds of the Turkish 8mm ammo with cupronickel jackets when it was cheap and I now shoot them through my BYF Mauser at about 2,400 FPS with otherwise modern components and there doesn't seem to be any fouling at that velocity. I do keep a close watch for it though as once it starts, it is the devil to remove, but as they shoot to about 2 1/2 MOA over 4895 and WW cases, I'll use 'em until they're gone.