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View Full Version : Ideal Theoretical Boolit Dimensions



Coote
11-21-2011, 06:12 AM
I know that in the end that nothing counts as much as practical results. But meanwhile I'd love to hear ideas on boolit dimensions. Like I've said before, I am fairly new to casting and hand loading.

I have two calibers I am casting boolits for, and I have been using three different moulds.

The two calibers are .308 Win and .303 British. For the purposes of this discussion let's assume that my particular barrels are close to 'standard'.

The dimensions given below may not be exactly right, but they are close and using them should simplify what I'm trying to say.

The 150 grain mould for my .308 casts a boolit with a .299" nose diameter and a band diameter of .309"

The 170 grain mould for my .308 casts boolits with a nose diameter of .302" and a band diameter of .312"

The 180 grain mould for my .303 British casts boolits with a nose diameter of .302" and a band diameter of .312" (interesting coincidence).

I don't yet have a sizing die. I had hoped to use boolits as cast from the mould. But I may need to get a .310" die for loading my .308" cartridges with the oversized 170 grain boolits.

I have already shot a group with the 150 grain boolits, and I think they are going to be OK but there is more testing to do.

QUESTION ONE: It looks like the 170 grain boolits designed for .30 caliber are going to get engraved on the nose, and there will be quite a bit of lead to get displaced seeing that the band diameter is about .004" over rifling diameter. I am intending to keep the speed of these to under 1100 fps. Is there a chance that these will shoot OK as they are? Is there any point to resizing the bands to .310" seeing that the nose is .002" over land diameter?

QUESTION TWO: The noses of the 180 grain boolits are .001" under land diameter for my .303. Is there a hope for decent hunting accuracy at lower velocities using these?

QUESTION THREE: I understand that the ideal dimensions of a boolit are about .001" larger in diameter on the nose compared to the barrel land diameter.... and .001" to .002" bigger at the bands than the true rifling diameter. Is this a good guideline?

I know that I can lap or 'Beagle' the mould to get bigger diameters, and I know that my questions may be answered when I shoot these boolits. But meanwhile I'd like to hear what really matters to experienced shooters.

I am very grateful for friendly atmosphere and the free sharing of knowledge here. I'm sorry about all the questions I've been posting, but I hope to be contributing more interesting stuff in the future. Thanks in advance.... Coote.

303Guy
11-21-2011, 07:15 AM
If they'll chamber then shoot 'em. The metal is going to get displace in a sizing die anyway. That 303 mold is on the small side. Not only small for the throat but small for the bore. Most 'standard' 303 bore's are .304 but they do vary widely. I have one with a .308 bore as made. (The other two oversize ones became that way with rust and use).

My idea of an ideal boolit size is one the fills the throat and seats without neck sizing. Usually slight neck sizing will be needed but a 303 has a fair size throat. (They say chambers are generous on them but mine are all fairly neat fits).

1Shirt
11-21-2011, 12:53 PM
IMNTBHO, the only thing that I know of that is ideal and is involved in reloading (in any fashion) is an old mold before Lyman took over. Ideal is kind of like the word best, which I find well overworked on this forum. For the individual caster and reloader don't think there is anything that is ideal or best. Someplace along the line, there will be something better in all probability. But then I have been called a skeptic by many! So be it!
1Shirt!:coffee:

sqlbullet
11-21-2011, 01:19 PM
303Guy nailed it. Shoot-em and see what you get. A thousandth or two of nose engraving is barely noticeable, and wont' really affect much.

Coote
11-21-2011, 05:53 PM
Good stuff thanks.

I hope to shoot some within the next week or so.