Redding Match Dies - Which ones?

Bart B

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Dec 25, 2005
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Skinny Shooter, full-length sizing dies have neck diameters small enough to reduce a fired case neck much smaller than a loaded round's neck diameter. Then the expander ball enlarges the neck enough to tightly hold a bullet.

Use a hole micrometer and measure the neck diameter of a 30 caliber full-length sizing die; it'll be about .330-inch or thereabouts. Next measure the neck of a 30 caliber round for that die; it'll be around .338-inch. A full-length sizing die's neck is always smaller than the neck of a loaded round.

So, lapping out a full-length sizing die's neck to a few thousandths smaller than a loaded round can be done. It's been done by many people. Such dies make much straighter sized cases than when an expander ball is used.
 

Bart B

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Dec 25, 2005
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More info on lapping out die necks.....

Remove the decapping rod/pin and expander ball from a full-length sizing die, then full-length size a case. Compare the sized case neck outside diameter to that of a loaded round.

This shows the difference in diameters I was talking about. With most cartridges, the difference is several thousandths of an inch.

Cartridge brass is springy; case necks spring back a bit after sizing. Try putting your expander ball back in a case mouth you've full-length sized and you'll see what I mean. A 30 caliber expander ball of about .307-inch diameter leaves the 30 caliber case mouth about .306-inch diameter.
 

Skinny Shooter

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[ QUOTE ]
Skinny Shooter, full-length sizing dies have neck diameters small enough to reduce a fired case neck much smaller than a loaded round's neck diameter. Then the expander ball enlarges the neck enough to tightly hold a bullet.
So, lapping out a full-length sizing die's neck to a few thousandths smaller than a loaded round can be done. It's been done by many people. Such dies make much straighter sized cases than when an expander ball is used.

[/ QUOTE ]
Now that makes sense to me and I'm pickin' up what you're laying down. /ubbthreads/images/graemlins/grin.gif Forgot about that reduction in ID that the die normally does (whoops). Sounds like an idea to try sometime.
What about just using a bushing FL die to get the same effect? And, couldn't you lap a bushing easier than the neck in a FL die?
 

Ernie B

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Feb 5, 2004
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Bart,
Thanks for that info. I can see where what you are saying makes sense, as well. I recently read an article by Richard Franklin of Richard's Custom Rifles in Vinton, VA, about his favorite 6mmAI 1000-yd. groundhog gun that he uses. This rifle has a BAT action with a 27" Krieger barrel. However, he said he went with the standard .274 no-turn neck because the extra aggrevation of a tight neck did not give him the added accuracy to be worth it. I hope to be able to get DocEd to put my 'hog rifle together for me this coming Spring. As I previously stated, it will be a 6mmAI and I plan on going with the no-turn neck on it.

As I stated previously, this long-range / precision stuff is new to me. But I've got one thing figured out for sure & certain already - I got one heck of a lot to learn!!
 

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