That's odd, my friend Barry in Dorset uses the Winchester ones for his Tolley underlever just fine. And that's what Armbrust does his loads in as well, I've fired quite a few of them through my Churchill.
http://www.precisionreloading.com has the clear Winchester hulls.
I may have spoken too soon on the Remingtons, I didn't realize that the newer ones are black again. For a long time the new hulls were green, if you saw black or yellow they were pretty old. It was the older black ones I'd heard of problems with. Apparently the new black ones have a unibody type hull.
Destry