Hi eveybody,
I recently boucht a CVA mountain muzzleloader in .50 cal, 1 :48 twist, along with 2 moulds, a Lee REAL & a Lee Minie. After casting some of the REAL bullets I found that the pressure required to drive them down the barrel varies quite a bit and accuracy was poor. This made me think that the temperature of the mould is important, seeing that the the aluminium will expand relative to the temperature of the mould, resulting in varying diameter bullets cast. Am I kicking up dust over nothing, or is this a real (pardon the pun) problem?
I apply some CVA slickload lube to the lube grooves on the bullets by hand, just before loading them... is the amount of lube being used allso important?
Should I use a different lube , or does this slickload stuff do the job?

Good question...but I'm going to have to do a bit of digging to be sure of the answer.

One thing to look at is how you are letting those bullets cool.l IDealy, would cast them and drop them on a dry padded surface, alwoing them to cool as slowly as possible. Different temperatures cooled quickly will end up at different hardness levels unless you are casting with pure lead...and all that is sold as "pure" may not be.

Have ahd the same problem with hardness varation when "quench hardening"...have to run the mold at the same temperature to get uniform results in hardness. Even if the lead starts out at the same temperature, bullets that hang up in the mold for a few moments before dropping into the quench end up at a different hardness.

Have a cure for hardness variation, but I'll have to check for temperature-diameter variation....but my first responce is "no", the diameter should be a factor of bullet alloy.

THOMAST,

If you are using pure lead the mould temperature makes little, if any, difference, so long as it is hot enough so you don't get wrinkling. The most possible would be .0001-.0003 which you will never notice. If you are getting measureable differences in diameter, then you probably have an Antimony bearing alloy of some type, which isn't what you want for either of the bullets you mention.

When you say the pressure needed to load varies, is that shot to shot? Remember that the R.E.A.L. engraves the rifling, and any powder residue will make subsequent loading much more difficult that a clean barrel.

THOMAST,

If you are using pure lead the mould temperature makes little, if any, difference, so long as it is hot enough so you don't get wrinkling. The most possible would be .0001-.0003 which you will never notice. If you are getting measureable differences in diameter, then you probably have an Antimony bearing alloy of some type, which isn't what you want for either of the bullets you mention.

When you say the pressure needed to load varies, is that shot to shot? Remember that the R.E.A.L. engraves the rifling, and any powder residue will make subsequent loading much more difficult that a clean barrel.

Alk8944 the way I figure it the expansion of the mould when heated up to different temperatures during the casting procedures (when the mould is full of molten lead, when cooling down to solidify the lead and when opening up the mould to drop the cast bullet out) would vary and this might have an impact on the diameters of the bullets..? surely if you have lead at a temperature just hot enough not to wrinkle the lead and you have lead at a temperature that caused "frosting" of the lead these 2 different temperatures would cause a difference in the expansion of te mould?
Is there a way to check the "pureness" of the lead? I bought some lead through a lead and soldernig supply company and they claimed it to be as pure as can be.

Yes you can check the pureness, but it isn't easy. You need to find the density, and that requires a 10cc glas graduate cylinder, a graph the NRA put out some years ago (and I'll xerox if you want the little article), and this formula:

weight in grains X .0648
-------------------------
volume in cubic centermeters

That .0648 figure is just to convert grains to grams, it's not some "magic" number.

Steps:
1. Weight of the bullet in grains.
2. Convert that weight by the .0648 conversion factor

(well call the resut of #1 and 2 "A")

3. Fine the volume of the cast bullet.
To do this you pour about 5CC of water into the glass graduate..doesn't have to be exact, but you do need to read the level exaclty (could be 4.8cc or 7.3cc...makes no difference).

SLIDE the bullet into the water gently..do NOT let anything splash or you'll lose some water and a lot of accuracy. Read the new water level exactly.

Subtract the first reading from he second and you have the volume in cubic centermeters.


Divde the result from #3 int "A" (the nuber we've been holding onto from step 1 and 2) and you have a number somewhere between 8 and 11.5.

The 11.5 is about a spure as lead you can buy gets...call it 100% lead. 50-50 bar solder will run about 8.7-9.0 on this scale. Wheel weight about 9.7 to 10.5.

Problem is, it only tells you aproximately the lead content...give no clue to what is in there besides lead, just an aproximation of the amount of lead...and if you ahve some odd ball mix with some really light elements, it tosses the graph way off at the bottom end...but lead is still lead, and the closer you number comes to 11-11.5, the more pure the lead.

Thanks ribbonstone, its just what I needed. The REAL bullets that I've been casting weigh out between 319.5 and 320,7 grains (theyre supposed to be 320 grains) surely this allso indicates that the lead I'm using is pretty pure?

Thanks ribbonstone, its just what I needed. The REAL bullets that I've been casting weigh out between 319.5 and 320,7 grains (theyre supposed to be 320 grains) surely this allso indicates that the lead I'm using is pretty pure?

That's an assumption...but it depends on how the mold was cut.

A simper test would be to melt down just enough pure lead (buy a box of Honady muzzle loading ball...they are close to pure) and cast one from that mixture as a comparison. We an sssume that the lead ball Hornady uses is about as pure as you'll find, so can calculate the percentage of difference from your normal alloy.

But on a guess, unless you are cleaning between shots, the bore is going to get more difficult to load...it comes and goes in an irregual pattern as the wrost of the fouling is blow out/scraped out and redeposited.

Meanwhile, am going to cast a few this afternoon...and I'll take pains to "cook" afew to high temperature and compare them to the normal ones..and the few that may cast cleanly at too low.