12ga full bore dia

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Howdy all, been a while.

Was wondering what the ‘nominal’ full bore dia for a 12ga is?

thinking of getting a slug mold for a rifled barrel and rifled choke 12ga.

may try the current wasp waist sabot, not sure yet.

I know I do love my .626 dia 20ga mold in my rifled NEF.

Topic

[darrellsteenwykParticipant]

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i could use either use pure or WW’s, probably use something soft.

[Mike B.Moderator]

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The reason that I originally asked was the difference in the two final cast weights as you will see in the two attachments.
a 1.25 oz cast weight is ~ 546 Gr and a 1.5 oz cast weight is ~ 656 Gr.
That being said here are a couple of rough drafts with an approximate super sized .626 to .730
the draft when cast in WW is approximately 648 Gr, with PB the weight goes up to 668 Gr.

[darrellsteenwykParticipant]

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What alloy do you plan to cast it in.
Pure lead or wheelweights…?
What was the original stopper to reusing the original tooling was changing the tooling to get rid of things like a crimp grove…

no stopper I know of.

[darrellsteenwykParticipant]

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nice, you could make the lube grooves deeper and wider to increase length a bit

instead of a trun cone nose, put a ‘lip’ on it before the trun cone starts. Helps unroll the roll crimp.

maybe a smaller meplat…

i cant get my autocad to work… otherwise I’d post up a pic too.

[Mike B.Moderator]

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There is I believe a tooling limit to making the lube groves a bit deeper.
Also it may make it more fun to drop the casting out of the deeper lube groves.
How much deeper do you want them…?

I will look at the adding a lip to the front diameter tomorrow morning or much later tonight at O dark 30 hrs…

[darrellsteenwykParticipant]

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I dunno, how much deeper can the lube grooves be made? I’d say a tad more not excessive.

maybe make the lube groove wider, at least as wide as the driving bands.

[Mike B.Moderator]

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Approximate requested dimensions please.

[darrellsteenwykParticipant]

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.74 on the lube groove width, and .50 on the middle drive bands, the top and bottom drive band look good, no rush. I’m out for the night now too.

[Mike B.Moderator]

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I tend to think that this may be something like what you are wishing for.
With pure Pb alloy set in the program calculations… the predicted cast weight comes out to ~ 649 Gr which is about 7 gr shy of 656 Gr or just shy of 1.5 Oz.
You have your .074 lube groves and .050 belts as requested…
Any additional alloy material such as tin… will tend to make it lighter than that…

[darrellsteenwykParticipant]

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yes, looks good. I would try reducing the meplat to about .60 for a bit more “aerodynamic” hahaha but actually it would aid in roll crimping too.

is the ‘ledge’ from the nose the same indention as the lube grooves ?

[Mike B.Moderator]

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If you look closely at the 730-649 you will see at both ends of the volume notation below the drawing sketch a .690 diameter number…
Your ledge is .690 tapering to .680.

[darrellsteenwykParticipant]

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ah! thanks, my pic is kind of skewed and the numbers were jammed together.
Looks good!

[Mike B.Moderator]

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if you are good to go with that drawing… then I did not need to post the 730-634 74 50 600 design sketch, with the .600 meplat…
By reducing the meplat to .600 instead of 680 one reduces the 649 gr cast bullet weight to around 634 gr… That’s with pure PB.
As I said previously any tin and the alloy gets lighter… Unfortunately even if the 649 design as shown is cast in a very hard alloy you still will be a good bit heavier than an ounce and a quarter…

[darrellsteenwykParticipant]

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I dunno man, I really like that .60 meplat

[Mike B.Moderator]

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Then at this point I will leave you to man the fishing pole…
That being said adding an HP to the .600 will help to reduce the weight to a 1.25 or 1.125 Oz weight…
You are now back to the 10 man new tooling design state…
Take Care, & Stay Safe…

[Author]

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