Boolit size and mold temp

[ChuckS1]

Quick question for y'all. I have an older Lyman 452488 mold that I just picked up. Ran off 50 today and they all seem to be about .450-.451 in diameter. I kept my alloy (straight WW) temp at around 750 degrees, according to my thermometer, but the boolits are frosted and I was castng at a pretty good clip, not letting the mold cool down. Just pour, drop, pour, drop, etc until I had 50 nicely filled out boolits.

So, since I got frosted boolits, I figure the mold got too hot. Reading some other posts, the consensus is that a mold that's too hot will cause the alloy to shrink more when it cools in the mold, causing an undersize boolit. True?

If so, guess I'll run it at a slower pace tomorrow and see if that helps. Anybody got any ideas?

[JSnover]

Add some tin. I drop lots of frosty bullets but have no trouble getting the right size.

[ChuckS1]

I do have some 50/50 solder. I'll try that in the morning.

[runfiverun]

slow down the cadence and let the sprue suck in.
i got a 44 mold that casts the most beautiful iron grey colored boolits right from the start, i just need it warm and let it go at it's speed.
i just sit it on the edge of the pot,run another mold and when the other gets hot, i drop a couple from it and set it back up there and go on the other one again.
it just has a leisurely pace to it.

[WHITETAIL]

+1 on the tin.:-o

[243winxb]

http://www.redding-reloading.com/pages/bulletweights.html Bullet Sizes and Weights-
How to Vary Them

The bullet diameters and weights presented in this list are based on the use of Taracorp’s Lawrence Magnum bullet alloy (2% tin, 6% antimony, 1/4% arsenic, 91.75% lead).

You should be aware that bullet diameters and weights will vary considerably depending on the lead casting alloy used. This variation can be as much as 1/2% on the diameter, and 8% on the weight among the most commonly used casting alloys. For example, a .358-158 grain bullet might show a diameter variation of .002", and a 13 grain difference in weight.

In order to provide a hard bullet, and due to the availability of high antimony content alloys such as scrap wheel weights and type metal, many casters are using high antimony content alloys. SAECO moulds work well with these high antimony content leads, but you should be aware of the variations they may produce.

Of the most commonly used alloys, wheel weights (.5% tin, 4% antimony, 95% lead) will produce bullets having the smallest diameter and heaviest weight, with such bullets running approximately .3% smaller in diameter and 3% heavier than bullets cast with Taracorp's metal. Linotype will produce bullets with the largest diameter and lightest weights. This alloy will produce bullets approximately 1/10% larger and 3% lighter than Taracorp. Other alloys of tin and antimony, with antimony content above 5%, will produce bullets with diameters and weights falling between those cast from wheel weights and linotype.

Alloys containing little or no antimony will cast considerably smaller than wheel weights and in some cases will produce bullets too small for adequate sizing. Within the limitations given above, the weight and diameter of a cast bullet can be adjusted by varying the alloy’s antimony content.

The size and weight of bullets of a given alloy will also vary according to casting temperature. Higher temperatures will result in greater shrinkage as the bullet cools, thereby producing a slightly smaller and lighter bullet than one cast of the same alloy at a lower temperature.

[prickett]

The size and weight of bullets of a given alloy will also vary according to casting temperature. Higher temperatures will result in greater shrinkage as the bullet cools, thereby producing a slightly smaller and lighter bullet than one cast of the same alloy at a lower temperature.

Does this just apply to alloys or does it apply to pure lead as well?

[lwknight]

Excessively hot molds will cause more shrinkage. Normally , the alloy solidifies as the mold is being filled. If the mold is too hot, the fill is liquid till its already full then shrinks. And of course if the mold is too cold the solidification is premature and causes wrinkles.

I could not prove that casting temps from 650-750 were extreme enough to make any difference in final cast size in my testing.

Antimony does reduce shrinkage and will yield larger boollits. Antimony is not a lot of good without at least 2% tin and if you use more than 6% antimony, you need up to 4% tin to12% antimony.

If tin content exceeds the antimony content, you nullify the hardening of the antimony.

[243winxb]

http://en.wikipedia.org/wiki/Casting_%28metalworking%29
Does this just apply to alloys or does it apply to pure lead as well? It applys to both alloy and pure lead, both shrink in the mould as they turn from a liquid to a solid. Then the hot solid laying on the towel will shrink again as it cools to room temeratures. How much it shrinks, i do not know, a guess would be in the area of .0001" < just a guess. Only a few metals will expand on cooling (Iron) in the mould. See link

[prickett]

How can Lee claim their tumble lube dies produce bullets needing no resizing if size is based on both casting temp and alloy content?

Are they assuming a specific alloy and mould temp? (and, if so, I don't recall seeing that info. Seems kind of important to their claim to provide that info)

[lwknight]

Lee is saying that size is not exactly super critical. big enough to 1 or 2 1/1000 over is OK for general shooting.

[243winxb]

How can Lee claim their tumble lube dies produce bullets needing no resizing if size is based on both casting temp and alloy content?:?:

Are they assuming a specific alloy and mould temp?[smilie=b: (and, if so, I don't recall seeing that info. Seems kind of important to their claim to provide that info)http://www.leeprecision.com/cgi/faq/index.cgi
Mold weights

Our weights are based on a 1 part tin to 10 part lead mix. Harder alloys produce lighter bullets, and pure lead will produce a heavier bullet :groner:
Mold diameter tolerance

Our bullet mold tolerance is stated diameter, +.003/-.000 inch. [smilie=l:We gauge our bullet molds with a "go/nogo" gauge, which tends to result in bullet molds that run on the high side:roll: of the tolerance. You could probably use one of our standard molds at as-cast diameter with good results.:kidding:

If the bullets are oversize or out of round the mold is not fully closing. A build up of lube, splash of lead, or a burr on the mold block faces are holding them apart. Inspect the mold block faces and carefully remove anything that might hold the mold apart. Make sure to lubricate the locating pins with solid alox/beeswax bullet lube, Lee part number 90007. If these steps are followed the bullets will cast dimensionally correct.:bigsmyl2:

Real Bullets as per page 30 in the Catalog
Rifling-Engraved-At-Loading
Unique Cleaning Action
Easier, Faster to Load!
More Accurate:razz:

A solid bullet that loads easily even after many firings because of its unique cleaning action. Will not tumble. A perfect hunting bullet with heavy loads. Easy to cast. Shoots accurately even in greatly oversize barrels.

Real bullets are cast with a kind of taper in that each of the 4 drive rings is larger than the previous ring. This allows for easy starting into the barrel, and yet assures that the bullet will be tight in the rifling.
.45 bullet is .452 at the base and .467 near the nose
.50 bullet is .502 at the base and .517 near the nose
.54 bullet is .542 at the base and .557 near the nose
.58 bullet is .577 at the base and .592 near the nose
.44 bullet is .442 at the base and .457 near the nose

[ChuckS1]

Here's the first followup, if anyone's interested. I tried again but this time dropped the WW alloy temperature to 650 degrees and cooled the mold on a wet washcloth for a count of three between casts. Still came out at .450-.451. Ran them through my .452 and saw no evidence of any metal being removed. Drops through the cylinder mouths of my USFA .45 Colt with hardly any effort at all.

Guess I'll try some added tin next to see if that works.

[Echo]

Don't add much tin - anything over 3% is wasteful, and 3% ain't much. Five pounds (80 oz) of WW alloy would take a measly 2 oz of lead-free solder to optimize.

[243winxb]

Guess I'll try some added tin next to see if that works Yes , give that a try, let us know how that turns out. [smilie=l:

[ChuckS1]

Well, I added 4 oz of 50/50 solder to my ~10 lbs of alloy and tried again. Alloy temp was 650F and I did a slow 5 count between pours. Still dropped at .450-.451. Measured with a digital caliper, my old dial RCBS caliper and a new digital caliper. All the same measurements. Oh well... Guess I could beagle the mold, but i have too many other .45 molds that cast at .454, so it's not worth the trouble. :killingpc