Diameters for Ruger SuperBlackhawk

Dogpatch · March 30, 2014, 08:31 AM

I have an early 1970's Ruger SuperBlackhawk, .44 Mag that I purchased new. The barrel just in front of the forcing cone measures .427-8, front of the cylinder mikes to be .432. It probably has a total of a few hundred rounds thru the bbl. mostly factory soft points and hollow points.
A recently purchased a Lyman mould (#429215) 2 cavity, 210g. SWC casts (almost) #2 Alloy at .427. My H&I sizing die = .430 so it seats the gas check and lubes but not much else.
I would like to use the gun for plinking cans and stuff and so develop mild reloads. Do these numbers make sense ? Do I need a mould that casts 1 or 2 thou over the .427 bbl ? Does the .432 cylinder front number matter in this ?
Thanks for listening,
Dogpatch

g.willikers · March 30, 2014, 12:01 PM

Since the cylinder is larger than the barrel, there's no problem there.
If it were smaller, of course, the bullets would be squeezed down and ruin accuracy.
Usually lead bullets are sized slightly larger than the barrel.
Have you slugged the entire barrel rifling to make sure what size it actually is?
It's probably smaller than the forcing cone area.

**44 AMP** · March 30, 2014, 12:53 PM

as long as the bullet is at least a couple thousandths larger than the bore it should be ok. You will probably have to adjust a bit between what alloy mix and what speed give you the best results for both accuracy without leading.

you might find that with one alloy the powder used is more important than with a different one, as one combination of powder and bullet alloy might suffer more "base melt" than a different combination. This will have an effect on bore leading, too.

Slugging the bore is a good idea, so you actually know what you have to work with.

March 30, 2014, 08:31 AM	#1
Dogpatch Junior Member Join Date: June 16, 2011 Location: Hudson, Florida Posts: 7	Diameters for Ruger SuperBlackhawk I have an early 1970's Ruger SuperBlackhawk, .44 Mag that I purchased new. The barrel just in front of the forcing cone measures .427-8, front of the cylinder mikes to be .432. It probably has a total of a few hundred rounds thru the bbl. mostly factory soft points and hollow points. A recently purchased a Lyman mould (#429215) 2 cavity, 210g. SWC casts (almost) #2 Alloy at .427. My H&I sizing die = .430 so it seats the gas check and lubes but not much else. I would like to use the gun for plinking cans and stuff and so develop mild reloads. Do these numbers make sense ? Do I need a mould that casts 1 or 2 thou over the .427 bbl ? Does the .432 cylinder front number matter in this ? Thanks for listening, Dogpatch

March 30, 2014, 12:53 PM	#3
44 AMP Staff Join Date: March 11, 2006 Location: Upper US Posts: 28,833	as long as the bullet is at least a couple thousandths larger than the bore it should be ok. You will probably have to adjust a bit between what alloy mix and what speed give you the best results for both accuracy without leading. you might find that with one alloy the powder used is more important than with a different one, as one combination of powder and bullet alloy might suffer more "base melt" than a different combination. This will have an effect on bore leading, too. Slugging the bore is a good idea, so you actually know what you have to work with. __________________ All else being equal (and it almost never is) bigger bullets tend to work better.

March 30, 2014, 12:01 PM	#2
g.willikers Senior Member Join Date: September 28, 2008 Posts: 10,442	Since the cylinder is larger than the barrel, there's no problem there. If it were smaller, of course, the bullets would be squeezed down and ruin accuracy. Usually lead bullets are sized slightly larger than the barrel. Have you slugged the entire barrel rifling to make sure what size it actually is? It's probably smaller than the forcing cone area. __________________ Walt Kelly, alias Pogo, sez: “Don't take life so serious, son, it ain't nohow permanent.”