Breech plug material.

[rhs]

All,
My first post and I'm very impressed with the amount of technical info shared here.
I have recently been given a partially assembled kit which I am attempting to finish. One problem is a very poor inletting job on the breechplug tang. I have access to a machine shop and would like to make a replacement breechplug with larger tang dimensions. Is a low carbon steel (AISI 1018) suitable for this?

 

[Zonie]

IMO, although the exact material number might not be AISI 1018, all of the breech plugs and a lot of barrels are made out of low carbon steel (AISI 1018 or AISI 1020 and some are leaded steels to improve machinability) so you shouldn't have a thing to worry about providing you machine the threads within their specified tolerance. (The threads are the weak feature in the design and if you run a stress analysis you will find they are overdesigned on most modern muzzleloaders).
I would suggest class 2A or 3A thread, with class 2A being the most common.

 

[rhs]

Thanks,
Is there any advantage to placing a concave depression in the breech face. I've heard this gives increased velocities because it is more of a "shaped charge". If it offers no benefit I think the flat breech face would be easier to maintain.

 

[Bushwhacker]

Breech plug should be flat bottom for best results.
Yas 1018 is a sutable matl. for a breech plug. Lot's barrel makers today are using C1144 for their barrels. It's a stress proof matl.
BUSHWHACKER
Walk softly and carry a smoothbore :m2c: :redthumb:

 

[rhs]

Thanks
I also have Starrett No.498 low carbon steel. It appears to be very similar to 1018 properties and appears to be better quality than standard 1018 round bar.