BP and Pressure

histed · June 10, 2014, 06:37 PM

Until recently I've shot a .54 flintlock with patched RB and 90gr of FFg. Recently I acquired a .533 Minie mold that drops them about .538. I'm trying to find So my question is what are the early signs of too much pressure in this type of rifle? I've reloaded metallic cartridges for many years and know what to watch for there, but this has me a bit confused. Don't really want to eat my breech plug

mehavey · June 10, 2014, 07:02 PM

You are not going to eat the breech plug shooting (real) black powder.

That said, start at 45gr/2F and work up 5gr at a time looking at groups.
When the group blows up (because you're blowing the Minnie's skirt out
on muzzle exit), that's the limit.

Slamfire · June 10, 2014, 08:32 PM

Quote:

Until recently I've shot a .54 flintlock with patched RB and 90gr of FFg. Recently I acquired a .533 Minie mold that drops them about .538. I'm trying to find So my question is what are the early signs of too much pressure in this type of rifle? I've reloaded metallic cartridges for many years and know what to watch for there, but this has me a bit confused. Don't really want to eat my breech plug

A Minie ball will blow its skirts with too high of pressure, and that pressure will be below any pressures that might damage the gun.

For me, with round balls, too much pressure was evidenced by blown groups. There is data out there, Lyman used to print a BP handbook, I would stay within the upper limits.

histed · June 11, 2014, 04:49 AM

Thanks guys. Slamfire - I also heard about that book, but haven't seen it. Maybe I'll try fleabay or amazon.

June 10, 2014, 06:37 PM	#1
histed Senior Member Join Date: April 9, 2013 Location: Central PA Posts: 254	BP and Pressure Until recently I've shot a .54 flintlock with patched RB and 90gr of FFg. Recently I acquired a .533 Minie mold that drops them about .538. I'm trying to find So my question is what are the early signs of too much pressure in this type of rifle? I've reloaded metallic cartridges for many years and know what to watch for there, but this has me a bit confused. Don't really want to eat my breech plug __________________ You Have enemies? Good. That means that you've stood up for something in your life. --Winston Churchill The right to buy weapons is the right to be free. -- A.E. Van Vogt

June 11, 2014, 04:49 AM	#4
histed Senior Member Join Date: April 9, 2013 Location: Central PA Posts: 254	Thanks guys. Slamfire - I also heard about that book, but haven't seen it. Maybe I'll try fleabay or amazon. __________________ You Have enemies? Good. That means that you've stood up for something in your life. --Winston Churchill The right to buy weapons is the right to be free. -- A.E. Van Vogt

June 10, 2014, 07:02 PM	#2
mehavey Senior Member Join Date: June 17, 2010 Location: Virginia Posts: 6,883	You are not going to eat the breech plug shooting (real) black powder. That said, start at 45gr/2F and work up 5gr at a time looking at groups. When the group blows up (because you're blowing the Minnie's skirt out on muzzle exit), that's the limit.