Need help with cast boolit weight

[tmc-okc]

I am having a problem I don't understand. My cast boolits are coming out much heavier than the advertised weight for this mold. The mold is a Lyman Devastator No. 429640 single cavity 240 Gr. mold. My alloy is 250 Gr. 50/50 solder to each 1 Lb. COWW. I am casting at 725 degrees. Boolits fall out of the mold and look fantastic after the mold warms up. I powder coat with Eastwood Lime Green powder and the HP cavities are cleared of any excessive powder before baking. I bake these standing on their base at 400 degrees for 20 minutes. The boolits come out of the oven to a water bath and all boolits are well coated and stand up to a 3 Lb hammer test without shedding any of the coating. I am sizing to 0.431”..The problem is these now weigh 261 Gr.s. I have checked my Lyman / Ohaus beam scale with Lyman Check Weights and an electronic scale with the same results. . What is causing the excessive weight?? I understand the boolits may come out 4-6 Gr;s heavier than the advertised weight but 21 Gr's. seems very excessive.

I am also looking for advice on loading these 261 Gr. boolits for my S&W 24-2 44 Special and I will be using Hodgdon HP 38 powder as I have 14 Lb of the stuff and powder is expensive to buy right now. I can’t find any reloading data using a boolit heavier than 240 Gr. for this cartridge using this powder. I am wondering if 3.0 Gr’s of HP38 would be a good starting load? These will be plinking boolits. I appreciate all your advice. Thank you.

[pworley1]

Adding more tin will make the bullets lighter.

[waksupi]

Weight varies a lot from stated weight on molds. Not a bit unusual. 21 grains heavier, just reduce the stated loads a bit, and work back up.

[Dusty Bannister]

Lyman cast bullet handbook 4th edition shows the Ly 429640 HP with a nominal weight at 250 with Lyman #2. Your finished powder coated bullet now weighs 261 grains. A difference of 11 grains.

Your alloy base of COWW has only .5% tin and perhaps 2.5% antimony. Plus the solder which is only half tin. You are comparing an alloy containing 97% lead and an alloy containing 90% lead weight difference between the designed alloy and your actual alloy. Not to panic.

[mehavey]

Re OP post and Dusty's

OP is not too far off expected #2 weight of 250gr
when actually different alloy:


The OP's bullets are fine given the alloy used.

.

[BLAHUT]

CUT POWDER BACK AND LOAD SOME UP AND TRY, THEN INCREASE POWDER TO GET TO fps YOU WANT ??

[GregLaROCHE]

It’s probably because of your alloy as others have said. Alloy temperature when casting can have an effect too.

[megasupermagnum]

That is a normal weight to see.

[canyon-ghost]

My 9mms are supposed to be 125 grain, they are not. They pour at around 130 grains.
Most of my molds will pour heavier than they should. That's one reason I weigh bullets and match up the weights.
Ron

[243winxb]

Lyman molds are regulated to their alloy. For lighter, add more linotype.


Powder charge- use starting load for 240 gr.

From Redding Reloading-

"Bullet Sizes & 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).

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.

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 1/3% 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 f rom 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."

[Dusty Bannister]

Post # 10
OP says he is using 240 grain nominal weight mold. It is actually a 250 Grain nominal weight mold. There is data for the 250 grain weight bullets, and specifically for this mold number. I do not think you intended to suggest he use data for a lighter bullet.

[243winxb]

Post # 10
OP says he is using 240 grain nominal weight mold. It is actually a 250 Grain nominal weight mold. There is data for the 250 grain weight bullets, and specifically for this mold number. I do not think you intended to suggest he use data for a lighter bullet.

Nope . OP did say a 240 gr mold? Or i read his post wrong? Ty for the correction.

[Dusty Bannister]

OP apparently had uncorrected typo because the mold nominal weight is 250, not 240.
Pointed out correct bullet weight per mold in post #4. Perhaps OP will come back and verify the mold number.

[OFFSHORE]

Another good idea is to sell the mold to me !!! I have wanted a Devastator mold for my arsenal. Your mold is good, like other have stated, just adjust your alloy for the bullet weight or lower your powder charge and work back up. All's good in da' hood.

[gwpercle]

Weigh the boolit before you size, lube and/or powder coat it .
The given weight should be based on as dropped from the mould .
Gary

[tmc-okc]

Gentlemen --- I must stand corrected -- Dusty you are correct the Lyman mold 429640 IS advertised at 250 Gr's. 243 Winxb - I apologize for the incorrect information. So my finished bullet weight of 261 Gr's is really not that far out of line given my allow mix.. That is good news to me. Does anyone have any data using this boolit at 250 Gr's with HP38 powder ? None of the resources I have provide any info above 240 Gr. boolits.. Would I be safe starting at 3.0 Gr's with HP 38 ??

[robg]

mine are usually heavier than mold weight except funnily my lee molds

[Echo]

Adding more tin will make the bullets lighter.

True. He's only getting less than 2% Sn, meaning he is casting dang near pure Pb...

[Tripplebeards]

When I cast 16:1 in my .430, 250 grain Lyman devastator thd average weight of my boolits drop between 261 to 263 grains before I PC and GC it. Best accuracy for me was with starting loads to mild loads with h110 and lil gun out of my 77/44. Even switching alloys to COWW and 50/50 pure and COWW I think it was closer to 258/259 grains on average if I remember. Tried some 80/20 COWW and pewter mix with a BH of 15.4. Didn’t get any expansion on deer at 1750 fps. I’m sticking with 7.5 BH 16/1 at 1600 fps till I connect with a deer. Hoping it will expand easily and dump a lot of energy for a big hole and quick recovery. Load data wise I used 240 grain jacketed ammo load data abd watched for pressure signs along the way. A max suggested book load of H110 was to much for my 77/44. My current load is a little more than a couple grains shy of max book load with excellent accuracy. I was loading some with trailboss out of my rifle and S&W 329NG. They are a hoot to shoot! Think I was around 900 fps out of my rifle if I remember and recoiled like a 22WMR.