When full length resizing brass, the portion of the case body immediately behind the shoulder... how much should it be reduced.

The cartridge is a 243 Ackley and the fired dimension is .4605"

Hey 308Sako, I doubt anyone can give you a definitive answer because of the amount of Variables involved.

Your Chamber would be a slightly different dimension than anyone else's. Same for the Die Set. Then the Case contracts a bit differently after firing from Lot-to-Lot, and how robust the Load was that got fired in it.

If you had a Chamber Cast and a couple of Fired Cases, the folks that make the actual Dies(RCBS, Redding, etc.) would have an excellent chance of providing that info to you.

I've heard some of them can make Custom Dies with only a few fired Cases. I'm not sure how that is possible without a Chamber Cast, but folks say they do it.

Best of luck to you.

My gunsmith used a Manson reamer and behind the shoulder fired is .460" and using a Redding Type S FL die .454" and that is the dia of a new 243 case. Hope that helps

HC gave you a honest answer, there are just too many variables that can affect the way the brass reacts to firing, and sizing.
Your chamber and die geometry are just two of them. As long as brass life is reasonable, and feeding and ejection are good, I would think the two are doing what they are supposted to do.
JMHO.....

If you owned a 6RemAI,243AI and 22-250AI and FL sized them with a Redding die the shoulder dia be .454". If you owned a 223AI and 222AI FL sized them shoulder dia would be .261". If you owned a 280AI FL sized dia would be .450".

As to reamers those can vary more than dies. I own two different brands of dies for my 280AI and varation between the two is only +.0005". I own 2 6RemAI RCBS/Redding no difference in the 22-250AI alittle differnce between Redding body die and FL -.0005". I only use a body die for sizing on the 222AI and also the two 223AI.

I'm sure all the others may have different dia that have comment and I'm sure they will let you have them for the 243AI dies they own.

HC is correct.
Butch

quote:

Originally posted by butchlambert:
HC is correct.
Butch

Well Butch since your a gunsmith what the dia on one of your 243AI reamers?

Tom,
I do not claim to be a gunsmith. I build hunting and BR rifles for myself and family. The same reamer can cut different size holes. I have cut many chambers with one PPC reamer to the exact same headspace and sometimes even though the brass will interchange, it may be a little tight in one chamber and ok in the other. It depends on your setup, method, and bore straightness. I loaned my 30BR reamer to a friend. His fireformed brass was .001" larger about .200 in front of the base than mine. Something in his setup allowed the reamer to cut heavier on one side.
I own no Ackley improved reamers. The last Ackley that I chambered was a 7-08 about 12 yrs ago. I sold the reamer. Nothing against the cartridge as it shot great.
Butch

quote:

Originally posted by Hot Core:
Hey 308Sako, I doubt anyone can give you a definitive answer because of the amount of Variables involved.

Your Chamber would be a slightly different dimension than anyone else's. Same for the Die Set. Then the Case contracts a bit differently after firing from Lot-to-Lot, and how robust the Load was that got fired in it.

If you had a Chamber Cast and a couple of Fired Cases, the folks that make the actual Dies(RCBS, Redding, etc.) would have an excellent chance of providing that info to you.

I've heard some of them can make Custom Dies with only a few fired Cases. I'm not sure how that is possible without a Chamber Cast, but folks say they do it.

Best of luck to you.

The die was returned from Redding this past week and all they did was shorten it to allow for the neck to be fully sized by the bushing and of course the shoulder to be bumped back for headspace reasons. The big however was that the excessive body taper adjustment was not addressed. The initial communication with Redding indicated that they have two different spec dies. One for the 243 40 degree and another for the Ackley version. My factory Cooper chamber is an Ackley and as such requires a larger body diameter. It stands to reason that the body should be minimally reduced to aid in the alignment of the bullet to the bore. I do have faith in Redding, and believe that it will be made good as their last communictation was to return the die for a replacment... Go Redding.

Thanks all for the as always informative replies.

quote:

Originally posted by 308Sako:
I do have faith in Redding, and believe that it will be made good ...

Hey 308Sako, I've got a lot of faith in them too. Good folks to deal with.

quote:

Originally posted by butchlambert:
Tom,
I do not claim to be a gunsmith. I build hunting and BR rifles for myself and family. The same reamer can cut different size holes. I have cut many chambers with one PPC reamer to the exact same headspace and sometimes even though the brass will interchange, it may be a little tight in one chamber and ok in the other. It depends on your setup, method, and bore straightness. I loaned my 30BR reamer to a friend. His fireformed brass was .001" larger about .200 in front of the base than mine. Something in his setup allowed the reamer to cut heavier on one side.
I own no Ackley improved reamers. The last Ackley that I chambered was a 7-08 about 12 yrs ago. I sold the reamer. Nothing against the cartridge as it shot great.
Butch

As you know how one chambers a Ackley is some of the problems depends on how headspace is set up.

I've got 9 Ackley chamber rifles and never had a problem guess. My first concern is dies more so than the chamber because I always ask how headspace is set.

Dies don't change and as far back as Speer wildcat manual #4 1959 they publish Ackley case dimension. The 257AI,270x257AI,7x57AI all measure at the shoulder .455". The 6REMImproved with 30 degree shoulder measure .456".

Nolser #5 manual has the 22-250AI at the shoulder .454" and the 30-06AI shoulders at .454". Speer from 1959 had the shoulder on the 30-06AI at .4535".

Tom, That is an excellent read as to what should be. And I agree once the specifications are set... so be it. I can only report on this one chamber and one set of dies. The loads were stout, but not approaching some of the more adventuresome I have read about. More wait and see what happens next for me.

Thanks for the insights.

Tom,
Just for the hell of it I measure some of my old 7-08AI as I saw I still had some. I was supprised. The sized ones were .453 at the shoulder and .461 on the fired rounds. No change in dimensions on the base.
Butch

Butch, Thanks for following through on the concept... enlightening isn't it!

Update: Got the new die back from Redding and the area in question now sizes .002 from the expanded state. I am anxious to see if accuracy is enhanced by better fitted brass.