I put a new scope on my Marlin Guide Gun 45-70 over the weekend. I took it out Monday to sight it in.
I had fired about 5 rounds and had it almost where I wanted it. A bit a readjusting and when I touched off the next round all I got was a mild 'pop'. I waited a few seconds and opened the action and the unburned powder fell out all over the action and the bench. Some of it was caked an all of it was a orangish brown color. (H4198). Luckily I was shooting my muzzleloader too and my jag fit nicely down the bore and I was able to knock the bullet out.
With the powder into everything I couldn't camber another round so I had to take it home and strip it down and give it a good cleaning. I pulled all the remaining bullets from the cases and emptied the powder into a container. It all looked fine. I resized 10 of the cases and reloaded them with the same powder. Took them out and fired them without any problem. Actually at 50 yds the first 3 rounds went almost in the same hole an one just outside. Did some fine tuning of the scope and shot off the remaining rounds with no problem.
Its a mystery what happened with that one round. I am very careful with loading. The only thing I could see happening is that something got into that one charge to contaminate the powder. But what I don't know. I never have gun oil out when I am loading, (it would have had to be a decent amount of oil to contaminate the powder, but the primer was fine). I use Hornady One Shot case lube.
Any ideas????