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View Full Version : Cast R.B.'s: What Do You Do With The Sprue?



Bigslug
02-10-2024, 10:36 AM
Rehabilitation of the Frankengun ASM 1858 revolver continues. . .

I scored an in-box 1970's vintage 2-hole Lyman .454 round ball mold off fleabay and got to work with some alloy from scrounged shotgun slugs. Easiest mold break-in EVER - - no adjusting heat, no adding tin, and no rejects after the third pour through about 11 pounds of metal. Where have these grooveless spheres been all my life?:p

By nature of the projectile being round, there is of course the little bit of "tail" from the sprue cut, and I'm wondering how to handle that on loading. Do I:

1. Try to seat it directly forward where the loading ram will tend to mangle things a little anyway?

2. Try to seat it directly rearward so it's in the slipstream in flight?

3. Seat it sideways so the loading process swages it off with the rest of the ring, and let the act of firing finish the job? Seems to me like this is the best approach.

What say the venerated elders?

pietro
02-10-2024, 10:42 AM
.

FWIW, while the balls can be rolled between two flat metal sheets to swage down/spread/disappear the sprue; I just load them with the sprue towards the muzzle.

YMMV

MostlyLeverGuns
02-10-2024, 10:47 AM
Normally, I put the sprue up. I do put a dab of epoxy in the ball seat of the loading lever to avoid marring the ball when seating. You can also put a bunch of the round balls in a a case cleaning tumbler and run it to smooth off/pound down the sprue.

scattershot
02-10-2024, 10:49 AM
I load sprue up. If you want to eliminate the sprue entirely, just put them in a tumbler for a few minutes.

Bigslug
02-10-2024, 02:05 PM
Case tumbler. . .cool! Figure I'll try the sideways / swage-off idea to see what it does, but that sounds like a winner.

Driver man
02-10-2024, 02:18 PM
Seat it with the sprue facing the muzzle. A cast ball can develop voids which occur near or at the sprue. Seating sideways may cut the sprue but wont eliminate the voids. A ball is more off ballance when the centre of gravity rotating at high speed throws the ball off. This may not happen all the time, just when you dont need it to.

LAGS
02-10-2024, 02:29 PM
I usually put the cast balls in my rock tumbler that I use for making my BP.
Tumbling them not only rounds off the sprue , but if there are any voids in the ball , they show up almost right away.
The polishing tumbler does the same , but just takes a little more time since it isn't bouncing the balls as much as the ball mill does.

hc18flyer
02-10-2024, 03:04 PM
.

FWIW, while the balls can be rolled between two flat metal sheets to swage down/spread/disappear the sprue; I just load them with the sprue towards the muzzle.

YMMV

I use an embroidery hoop to contain them while rolling around between two steel plates. Usually I simply orient the spruce towards the muzzle. My shooting isn't good enough to tell a difference. hc18flyer

HamGunner
02-10-2024, 07:07 PM
I put the ball sprue up and the ram or the ram rod usually rounds the sprue off during seating to the point that the sprue is not really protruding anymore.

I have all sorts of sizes & brands of round ball molds and actually I have one Lyman and one Lee that leave virtually no protruding sprue. They do leave a bit of a flat spot on the ball that is near ball diameter, so they do leave a mark, but I doubt it bothers things like a sprouting sprue.

I have plenty of molds that leave an excessive amount of sprue sprouted out from the ball, so I am thinking of taking the sprue plates off and shaving just a bit off the tops of a few of my favorite molds to reduce the height of the sprue.

Arkansas Paul
02-11-2024, 01:16 PM
None of the above.
I put them in a rock tumbler before bed. When I get up in the morning, I turn it off and the balls are smooth as can be.
I do this with buckshot and with balls molded for BP use.

indian joe
02-11-2024, 08:02 PM
1) Use a LEE or Pedersoli round ball mold
2) tumble balls in a canvas bag with a squirt of powdered graphite
3) load em any which a way cuz cant see sprue anymore
4) if none of above - OR - you pedantic about this - load em sprue up - Sam Fadala did extensive testing for his book "Blackpowder Loading Manual" and results were could do just about anything to the front end of a ball and it still shoot good but dont mess with the rear end of it at all - the BPCR blokes know this stuff deformation (gascutting or whatever) of the base kills accuracy.

Kenny R
02-21-2024, 12:16 AM
I usually put the cast balls in my rock tumbler that I use for making my BP.
Tumbling them not only rounds off the sprue , but if there are any voids in the ball , they show up almost right away.
The polishing tumbler does the same , but just takes a little more time since it isn't bouncing the balls as much as the ball mill does.
I cast .490 rb’s for my 50 cal, then tumble them in my harbor freight tumbler. At the end of the cycle I incorporate some birdshot in the mix to finish them off. They come out as smooth and shiney as can be, with hardly any sprue visible

stubshaft
02-21-2024, 01:00 AM
Sprue up!

Abert Rim
02-21-2024, 09:47 AM
I have been pleased by the virtual lack of sprue on balls cast in the Lee molds.