choosing die size.

[birdshot]

Ok, I'm at the point of choosing a mold, I measured my cylinder and all 5 were .511. From reading on this forum I believe I should choose a bullet diameter of .512.

So do i get a mold of .512 diameter? or to allow for shrinkage, should i get a larger diameter and plan on resizing down to .512? Gas check or no GC? not planning on velocities over 1200fps.

If it matters I would like a finished weight of around 400 grains.

I did try to search this but didn't see definitive answers. so apologies in advance. Unable to change title to say mold size.

[mdi]

Type of gun? Normally for my casting I prefer to size all my cast bullets. For this a bullet dropping .003"- .005" from the mold works quite well. For revolvers I size to the same measured diameter as the cylinder throats. For semi-auto handguns I normally size to the chamber throat diameter. I don't use many gas checks anymore as I get good results from plain based bullets with proper bullet to gun fit, and a good lube

[birdshot]

The mold would be for a BFR chambered in 500 Linebaugh.

[pworley1]

I am not sure you can put a .512 bullet into a .511 hole.

[fredj338]

I size everything. As cast size varies with alloy & temp so I want as close to identical bullets as possible from batch to batch.

[fredj338]

I am not sure you can put a .512 bullet into a .511 hole.

Of course you can, with a bit of force behind it.

[243winxb]

Mold companys regulate their molds with a certain alloy. The alloy containing the higher percent of antimony, make the larger as cast diameters.

Lee 10 pure- 1 tin. Lyman #2 90% Lead, 5% Tin, 5% Antimony. Others may use wheel weights, 95.5% lead , 0.5% tin, 4% antimony. (Not a standard alloy)

Size bullets down as little as .001" to a maximum of .003" Bullets can be sized down more, but Lyman has said sizing down more the .003" hurts accuracy.

The sizing die will produce larger finished diameter bullet if using a higher percent of antimony.

[El Bibliotecario]

I am not sure you can put a .512 bullet into a .511 hole.

This mindset led me to spend years cleaning leaded bores resulting from using too-small bullets.

[mehavey]

...bullet diameter of 0.512"...

^^^^ THIS ^^^^

Go to Tom Ellis and order 0.513" cut for Lyman #2.
Size/uniform to that 0.512" after casting.

[birdshot]

thanks im looking at those now. single, double or triple cavity for newbe? I have a collection of lead maybe 65 pounds and some pewter ashtrays. Currently my set up is steel pot made from pipe, plumbers ladle, and Coleman gas stove. Also plenty of pine saw dust.

[birdshot]

Now I understand what size mold to get. Now in keeping with my desire to budget cast im looking at the Lee sizer which works with my single stage press.
I won't ask my next question as i believe there could be strong feelings concerning the answer. Thanks for everyone for taking the time to help me understand a little bit more of casting.

[mehavey]

Double cavity is most practical on balance.
Lee sizers are just fine.

[243winxb]

https://accuratemolds.com/FAQ.php

Why does the order form require that I select a casting alloy?

In order to produce the requested bullet diameter, I need to know how much tin is in the alloy. All applicable alloys shrink as they solidify. The more tin, the less shrinkage. The alloy choices in the drop down menu are listed in order of expected shrinkage, from greatest to least. If you intend to use varied alloys, choose the most appropriate one that's highest on the list, so that other alloys with more tin will be a bit larger.

When ordering, choose your "Casting Alloy"

[243winxb]

https://www.redding-reloading.com/on...-moulds-charts

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."


I add linotype for larger & harder as cast bullets.

[birdshot]

I took Mehavey's advise and got a 51-450 mold. I went with aluminum for cost reasons since I have yet to cast my first bullet. I did not realize it was five weeks out. Thanks to Dusty Banister who has been mentoring me I will be able to practice with two of his molds until the varsity shows up.