Resizing reamer Specs

Earl Fouraker

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I’m curious as to what dimensions everyone specs their resizing reamers to? JGS states their standard is -.004 under body dimension.

I was thinking .002 would be better....what’s everyone’s opinion?
 

Mikecr

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Well 4thou of actual squeeze would be pretty extreme. And if their standard chambers are so far oversize I'd seek better advice.
You're right, 2thou is plenty enough.
 

phorwath

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Well 4thou of actual squeeze would be pretty extreme. And if their standard chambers are so far oversize I'd seek better advice.
You're right, 2thou is plenty enough.
Case body springs back, same as a case neck. 0.004" resizing results in maybe 0.002" less diameter than the chamber wall.

I don't see an accuracy degrading issue with that 0.002" case body clearance. Rather have the shells feed, than difficulties closing the bolt.

How much less than chamber diameter do you order your resizing die reamer?
 

phorwath

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Well 4thou of actual squeeze would be pretty extreme. And if their standard chambers are so far oversize I'd seek better advice.
You're right, 2thou is plenty enough.
I think JGS is recommending their resizing die reamer, used to cut a resizing die, be cut 0.004" less in diameter than the chamber reamer used to cut the rifle chamber. We talking apples to apples?
 

L.Sherm

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Well 4thou of actual squeeze would be pretty extreme. And if their standard chambers are so far oversize I'd seek better advice.
You're right, 2thou is plenty enough.
I've got several JGS chamber reamers and there excellent only other one I would consider is Manson.
The other Oregon reamer maker forget it.
 

Mikecr

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No brass springs back 4thou, anywhere. Not even close to that.
Necks spring back 1/2thou to 3/4thou, near webs, maybe 1thou.
 

J E Custom

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I believe the best advice is to go with the reamer makers recommendation. I have many resizing reamers that were cut with the chamber reamers for my wildcats and they perform very well.

I have made most of the dies for these cartridges and been very happy with the results, so my experiences have all been good following the reamer makers advice.

J E CUSTOM
 

phorwath

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No brass springs back 4thou, anywhere. Not even close to that.
Necks spring back 1/2thou to 3/4thou, near webs, maybe 1thou.
I thought I stated 0.002" spring-back. Case necks are softened and annealed, so less spring-back. Case bodies aren't, so greater spring-back in my experience. And the thicker the case body, the greater the spring-back.

What's your primary concern with 0.004" undersized resizing die reamers? Do you think they'll work the case body brass excessively, such that cases will fail and fall apart there before elsewhere?

How much undersized in diameter do you order reloading die reamers, compared to the chamber reamers?
 

Mikecr

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YOU SAID
Case body springs back, same as a case neck. 0.004" resizing results in maybe 0.002" less diameter than the chamber wall.
This is dead wrong. A case body does not spring back that much, and necks even less. 4thou of squeeze does not provide 2thou of clearance.
2thou would be reasonable squeeze for larger hunting cartridges IMO.

Better yet, and what I've been doing lately is having body dies custom fit from fully fire-formed cases.
On this, I tell the die maker what squeeze I want. I do not leave this stuff to anybody else.
 

can1010

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stick with the reamer makers recommendations. if you don't think that brass will spring back .002 or more you need to look up all the problems the 6.5 PRC guys are having when they run upper end hunting loads. 3-4 loads on even ADG brass and they are getting stiff bolt lift and clickers. we have chamber cast the dies and they are set for .0035-.004 size at base but are only giving .001-.0015 of actual size because of spring back. leave well enough alone unless you are only running low end loads.
 

phorwath

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Well it seems we have some disagreement. A conundrum, of sorts...

I'm still waiting for someone who disagrees with the 0.004" reduction to explain how a 0.004" resize results in any traumatic crisis to accuracy or case life. Why not be safe with the 0.004", rather than sorry, if there's no big penalty to 0.004".

Gotta believe JGS has more experience with this than all the rest if us combined! 10x over!

But hey, they could be wrong, for some reason that nobody has explained. Explanations please?
 
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phorwath

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stick with the reamer makers recommendations. if you don't think that brass will spring back .002 or more you need to look up all the problems the 6.5 PRC guys are having when they run upper end hunting loads. 3-4 loads on even ADG brass and they are getting stiff bolt lift and clickers. we have chamber cast the dies and they are set for .0035-.004 size at base but are only giving .001-.0015 of actual size because of spring back. leave well enough alone unless you are only running low end loads.
What fun are low end loads? Might as well shoot a cork gun, or 22 LR. :D
High is where the action is.
 
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