I posted in one of Mako's threads on BP shotshells about some old commercial shotshells made with Pinnacle (APP) in paper hulls. I bought them from a retiring shooter, and they must have been 15 years old. Anyway, the boomed just fine but the paper had degraded so it split badly and the heads tore from the hull upon extraction. So I think it would be okay in properly loaded metallic cartridges. Major, I did the same as you with some of this stuff - I dissected 4 rounds so I could reload a few of the paper hulls with BP (they disintegrated just like with the Pinnacle, so the paper was already degraded) - and the powder in those shells was like a rock which I chipped out with an ice pick. Anyways, I took those 4 shells worth of powder and chunks and set it off inside a sheet of newspaper on the back porch. It whooshed and smoked just fine!