Yikes! Anyone that can afford that might as well move on up to .50 BMG. I'm still grumpy because .22 lr is over 2 cents per round.
The 5.7mm cartridge was introduced as a rifle round. Steel core bullets were sold for it, as they are perfectly legal for a rifle.
I didn't know that. Is there no ammo available in 5.7mm w/o a steel core? Many kinds of cartridges are made with steel cores and numerous guns in a given chambering will fire them. Of course. I wouldn't call my 30.06 hunting rifle an "armor-piercing rifle" just because they make 30.06 cartridges with steel core bullets.
Lots of it - the ammunition with standard bullets is still legal to import and legal for dealers to sell. You can get polymer tips or hollow points for $30 - $40 for a box of 50. I expect there’s an FMJ round, but we don’t carry it.