Found the article. Precision shooting Sept 1999 copy. "Short Primer on Primers partII" by ML McPherson. Very detailed article that showed more power in a 210 primer than even a 215 when tested in a jig for moving a wieght. Found that strange. But 215's caused higher velocity and pressure. Also showed significant differences in Primers from 1970 lot compared to 1995 lot. If you ever get a chance, its a good article.