Hollow point pin size??

[wwboolitmaker]

In the process of converting a lee two banger to a hollow point mold. It is the lee 457-450-F. What I am wondering is what diameter should my pin be? Could someone with a similar profile mold that is hollow pointed give me some specs to go off of? Once I get the specs and finish the mold I will post some pics.

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[beagle]

Rule of thumb is 1/3 the diameter of the bullet rounded to the nearest common size. I'd use a .156". Depth is 1/2 the length of the bullet.
These rules are not hard and fast but what us experimenters have always used. You can go up and down and deeper or shallower in depth but these rules seem to work pretty well and I've done about 70 HP conversions./beagle

[fredj338]

It depends on alloy & vel. My higher vel bullet molds have a shallow, maybe 1/8" deep, cup point pin. It will usually be about the meplat diameter. This prevents the bullet from fragmenting at higher vel. For lower vel loads I like a pin that goes deeper & still about the meplat diameter.

[Mk42gunner]

I'll try to find my 457122 tomorrow to get some real measurements from.

Going from memory, and a bit of guess work, I would make the pins from 1/8" stock with a taper to about half or 2/3 the boolit length. Expansion will be dependent on alloy, impact velocity, and the size of the hollow.

IIRC the 457122 was designed to use 20-1 and BP velocities.

Good luck,

Robert

[wwboolitmaker]

This is what I ended up with.

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