The other day, i quit working this plug when it looked like a headless bolt. Today, i went back to work, and milled the flats.







After the flats are milled the threads need work, and this is done with a 'thread chase'. Then i hit the edges of the threads with a wire brush, and emery paper. Now the breech plug is nearly done.








The final step is to 'polish' the primer pocket, which helps with primer removal.





Then on to installing the plug in the rifle, and see if it works. What was desired here was a 'crush' of the STS primer, which makes for a seal, and thus no blow by. The new STS primer measures 0.2935" long.












When the rifle is put into battery with vigor, the STS was 'crushed' about 0.003".

Somehow, this plug was made the right length, the first time. I musta held my mouth just right whilst working it. It was my intention to make it some too long, and then sand the powder end shorter tiny amounts at a time until the desired head space was reached.

I'm curious here Ron (and certainly out of my league).

I understand that you are machining the primer pocket to a specific depth to obtain a crush fit based on the overall length of the primer.

What happens if you make the pocket deep enough to accommodate all primer brands, and make the plug long enough so there's a crush fit of the primer flange between the breech plug and breech face? Wouldn't that provide a gas seal? Would it be overly difficult to remove a spent primer?

You certainly know more about this muzzle loading stuff than i do, but i am trying to picture how to get my fingernail under the primer rim, without some space there.

Looks good, cant wait to see the results. And yes a BP that would accept all Primers would be one to consider.
(BP)

The OEM breech plug accepts all primers. All primers are not the same length. This means the shorter primers will be loose. It will take a better man than i, to make a breech plug that will 'seal' with all primers.

Your right......and not about being a better man.
(BP)

I admire your work Ron. I work with wood all the time but I don't have the tools to do much with metal.

The breech plug shown being made is still 'new', but this one i used yesterday, and the day before, is very nearly the same; like within 0.003". The group is 5 shots. The range was 102 yard, and it was shot from the cabin of my pick-up. The Accura has a peep sight, and i am gettin' ready for our muzzle loader season. Bullet is 300g Gold Dot.