Lucky - weak primer in the lot, is what I mean by a "bad one", if all the rest functioned properly. A weak flame would indeed do exactly that, partial scorch and burn. Even a .45/70 does better with a mag primer when using IMR 3031. In large quantities and straight cases, most powders need a strong primer. I never had a problem after switching to AL8 * Kapok filler for light loads with light cast bullets using standard primers, and magnum primers for all other loads along with some testing of John's dual primer experiments.

Sometimes as suggested, one must use a stronger primer with some powders, especially when there is a large charge of powder.

Even in the little 2" straight sided .458 case, I went with CCI250's for all loads from then on - suggested by 'Old John' as many called him. P.O. Ackley might have said something like that in one of his letters as well. I only spoke with John B. on the phone, but corresponded with P.O. and Elmer. Quite the gentlemen they all were. We are diminished, without them.