Yes, we have seen them. The FPB=Flextip Projectile Blackpowder. That are $17 for 15 at Gander MT, again about $1.00 each, Walmart has them also. The underside expands to grab the rifleing, similar to the Powerbelt skirt, except this is made of copper or copper alloy. They look like an excellent MLer bullet, should be great for Colorado and other no sabot states. Should be good also for flintlocks with real BP.
Chap