Build my own luber/sizer dies

After someone slapped me in the head..reminding me that I own a fair selection of pretty good machine tools...Ive decided to build my own
lube/sizer dies, to fit the (4) RCBS/Lyman lubricators I own.
I occasionally want to experiment with oversized bullets and at $30-35 each...plus shipping...it could get damned expensive..
Some interesting things that Ive found while investigating and blueprinting the die body OD and ID...
If the lube sizer die is marked .311..the die actually is .310-3.105. Ive checked this on at least 5 dies, of various manufactures..and its always Smaller than whats marked. Id assumed..evidently incorrectly..that casting lead didnt have any "spring to it"...IE..if I squeeze it down to a half thousand or even a thousand (more on this later)..the lead will spring back bigger than the size of the die.
I found that rather fascinating. Either the lead springs back...or the manufactures used damned poor QC when building those dies.
I checked a range from .266 -.457..and the bigger luber dies ran as much as .002 smaller than what was marked.. IE..a .455 gage pin was a snug fit.
Anyone ever make their own lube sizer dies? Any links or data?
I also noted that the pusher pin in the center..typically was nothing more than a dowel pin. And may be as much as .008 undersize. Im trying to figure out why that is..other than "cheap". NOW I understand why some of my bullet sizing/lubing sessions would have lube dripping out the bottom of the lubricator press on my foot. Not a lot..but some.
Anyone got any idea of why the tolerences are so freaking big? In this day of cheap centerless grinders and whatnot...that should never happen. I understand that bullet lube is pretty thick and it might not squirt out of the die at the very low pressures we are putting on it...but...blink blink...come on!!.....008"??????
Ill be making some dies...the way I THINK they should be made and post the results here. I suspect we have been falling back on the High Quality Standards of the several suppliers..and this may have some bearing on inconsistant results Ive had over the years. Both in accuracy..and bullet diameters from batch to batch.
Anyone have any comments, suggestions etc?
Gunner
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wrote:

I suspect the reason is that cast lead bullets don't need to be that accurate. Back in the days of Harry Pope, et al, they were shooting as cast bullets and doing pretty well.
I also seem to recollect that lead bullets are upset, to some extent, by the gas pressure and that proper size is more important when using jacketed bullets then when using cast. Lyman, I believe recommends 0.001 - 0.002 over barrel diameter for lead bullets.
I would suspect that various batches of bullet metal might have a large effect on bullet diameter though.
--
Cheers,

John B.
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I do not think the lead is expanding after or while being sized.
So how are you measuring the hole in the die? I can remember reading a long time ago that the size of barrels was checked by pushing a lead ball thru the barrel and then measuring the lead ball.
Dan
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On Sat, 2 Mar 2013 05:38:40 -0800 (PST), " snipped-for-privacy@krl.org"

By doing just that and by gage pin
Gunner

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I know nuttin' about how-come, but here's a thought. Prior to their present dizzying cost, gas checks were a cheap way of getting some base protection and some additional velocity, particularly in .30, .44 and .45. Lead won't have spring-back, copper/brass sure does. So might be your under-sizing dies were intended to produce gas-checked bases of close to marked size. If you had some suitable .30 bullets and the original-style Lyman/Ideal gas checks, you could find out. Those would be the non-crimping sort with parallel walls. Now if you'd use the same die for a plain-base bullet, it'd probably slug up when fired. If it didn't do it far enough, the next step would be to go to the next size up( or go to a gas checked bullet), more profit for the Co., right?
Stan
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On Sun, 3 Mar 2013 15:30:10 -0800 (PST), Stanley Schaefer

Something to think about indeed. Speaking of gas checks..seen the Do it Yourself gas check makers?
http://www.freechex.net/
http://patmarlins.com
Lots of videos on YouTube on both of them.
And of course..there are lots of methods to making your own die sets
Ive played with both and before long, will have to invest in one or the other. Shrug. Im down to 20k of various sizes and nearly out of .30s
Gunner
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On 3/1/2013 11:02 PM, Gunner wrote:

I await your data!
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