Thoughts On This Recovered Cast Bullet

Hartkopf said:

I’ll be getting a .431 sizer.

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After sizing, check diameter, each and every time the alloy is a different batch.

For many years a 357 marked die gave a diameter ot .3575" after sizing. Exact same as my groove diameter.
Then one day i get leading. Seems the alloy didnt spring back after sizing. Diameter was .3572"
Now running .3581" with a different die.

Live and learn.

Texas10mm said:

Does that 429421 have a round grease groove? I ask because I've only seen them with a square grease groove.

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I had, maybe still have, a Lyman single cavity 429421 mold that was cut with a round grease groove.

To the OP, .44 caliber bullet molds are everywhere. Make haste to ebay where you can find all sorts of plain-base designs for not a lot of money.

35W

Hartkopf said:

So you are good with using a bullet the exact same size as the groove diameter?

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Its how i learned from reading years ago. I ended up using the standard cast bullet sizes for the most part. The standards are very close to my groove diameters of my personal guns. I have used my cast in many different brands of used handguns, when test firing them.

Standards- 358, 451/452, 430 & 309 for rifle.

In a perfect 44 mag world, the cast bullet drops from the mould at .431". Sized to cylinder throat diameter of .430" Barrel groove is .4295" Perfect imo.

Books tend to be the opinions of the writer. Times change.



The less a cast bullet is swaged down from mold to muzzle is best. Imo.

243winxb said:

Standards- 358, 451/452, 430 & 309 for rifle.

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After looking at the SAAMI 44 Magnum specifications, i will be doing more testing. Note diameters.

Sizing in a new .431" die, scrap lead is softer then my norm. Didnt add linotype.
Just an excuse to shoot more, when the county gets out of the RED.

Shooting air guns, rifle & pistol is just getting old & boring now.

Short story- bullets i can mark with a thumb nail are to soft. Produced leading.

Smelted pure, hardened lead pipe & 7 lbs of range scrap. Made 22 lbs of alloy. NO Linotype added.

Cast bullets can be marked with a thumb nail. Softer then what i like for testing.
Loaded 50 rounds with Unique @ 10.2 grs, WLP, Starline brass, 2nd loading. Bullet diameter .4315" weight as sized & lubed, 258 grs.

At 25 yards , accuracy was mediocre, but all in black of the 25 yard slow fire target. Average 83.2 Shooting with a 2 hand hold.

At 50 yards not good. So i benchrested , bag under forearms. Shot 5 rounds that had horizontal dispersion of 10 5/8" i would guess bullets skidding and/or slumping?

I will go back to my proven method of adding 1.5 lbs of linotype to my 10 lb Lee pot.

Side note- 44 mag Starline Brass- 2nd loading. thin case wall, light neck tension. A .429" expander did not touch the case , except for flaring/belling the case mouth. Will not buy again.

Hartkopf said:

Slugged my SBH barrel today. It is exactly .430 so I’ll be getting a .431 sizer. The bullets drop from the mold at .431 but are a bit out of round and range up to .432. My OCD will feel better if the bullets are perfectly round.

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Slug/measure the cylinder throats and size your bullets to the same diameter (using a slug, pin/plug gauge or expanding ball gauge. A caliper won't give accurate measurements of small diameter, under 1", IDs). If the bullet is larger than the throats, the throats will size the bullet down as it passes and if the bullets are smaller than throat diameter the possibility of leading is greatly increased. Measuring the cylinder throats also insures the throat diameter is larger than the barrel groove diameter. I have 7 revolvers that I shoot cast bullets in and this works well in all, good accuracy and no leading

Hartkopf said:

So you are good with using a bullet the exact same size as the groove diameter? I can carefully fine tune my sizer by honing and polishing to whatever is best. Is .001 over groove diameter just a rule of thumb or would .0005 over be better? I could just test all of this too but I would love to hear opinions from the experienced guys.

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It was either Ross Seyfried or Hamilton Bowen who wrote that the ideal revolver would taper from bullet to muzzle in .0005 steps. In other words, the bullet would be .0005 larger than the throats, which would be .0005 larger then the leade, which would be .0005 larger than the muzzle. There are very knowledgeable folks who disagree with that idea, though. I am not one of them, and I have found that those conditions can be made to occur through careful measurement and firelapping. Those guns are all far more accurate than I am and do not lead in any significant way, so I am a believer.

<edit> I will say, however, that I never have been able to reliably control bullet diameter to .0005". Measuring a relatively soft metal covered in waxy lubricant to that level of precision is beyond me. Even when I tried it, I could detect no measurable difference in accuracy - most likely because in a good revolver, even bullets controlled to .001" outshoot me despite the use of a bench and a scope.

The perfect bullet diameter may still lead the barrel.

"Plastic deformation-This whole relationship centers around the elastic limit for the alloy you are using and what the elastic limit is. The elastic limit is the point at which stresses can occur to an object and it will return to it's relative shape. Once you have reached the deformation stage it no longer returns to relative shape. This is a very simplified version of this topic as it pertains to engineering mechanics of materials.
This is meant to be a guide and to keep you within safe/acceptable limits for pressure and alloy for your purposes. Obturated bullets do not mean that the shape has went through plastic deformation, just that it has expanded and stayed within the elastic limits of the alloy.
The formula does not take into account other factors that aide in reducing friction and thus combined forces on the cast slug.
Another factor not talked about is the pressure curve of the powder/cartridge combination. Does it spike quickly (fast burn rate pistol powders ) or is it a gradual increase (full case of slower powder). Protection of the bullet base can also be a factor, we routinely do this by gas-checking."

Match pressure to BHN.


https://en.m.wikipedia.org/wiki/Plasticity_(physics) Plasticity describes the deformation of a material undergoing non-reversible changes of shape in response to applied forces. Obturate means to block or obstruct.

Soft vs hard alloy test. 44 mag. Diameter .4315" vs .430"