Dang, I guess I need to readjust the headspace on my .260AI

I have a .260AI that I have been shooting for 9 months and have come to the conclusion I need to readjust the headspace because the Redding body die will not bump the shoulder back.

I have shot Rem, Nosler, and now Lapua brass with some cases having 7 or 8 reloads on them and haven't needed to bump the shoulder back yet.

The last load I shot, 47.5G H4831sc produced brass that takes a lot of of force to close the bolt on.

I measured the OAL to the shoulder with the Head and Shoulder gauge and sure enough these cases need to be bumped back 0.002 to 0.003 to fit in the chamber and let the bolt close.

To my surprise the Redding body made the cases longer at the shoulder instead of shorter when setup with a hard cam over in the press.

The die must have increased the body taper and pushed the shoulder forward, at least that's what the Head and Shoulder gauge says. YIKES!

I have a set of Redding shellholders the go from 0.002 to 0.010 in headspace but none of them make any difference in the case OAL to the shoulder.

Is there any other solution to this other than adjusting the headspace on the chamber?

I set the headspace using go/nogo gauges to minimum headspace on the gauges and still allowing fireforming brass from factory .260.

I don't really want to make the chamber longer after doing load development ....

Anyone have any ideas?

Thanks ...

Call Redding - More than likely, they'll have you send the die and some fired cases to them. I had to do the same thing with a 223 AI FL sizing die. They ended up having to take several thou off the bottom of the die.

I had a similar situation after having my 204R re-barreled. I sent my sizing die to the smith that did the no-nut barrel install and he trimmed it ten thou. That fixed it. Also had a similar situation with my 6.5x55AI. This time I had set the barrel up with a go guage and tape on the end for no go. Instead of trimming the die I just modified my shell holder. Works the same as trimming the die.

I have a 6mm BR body die (Redding) that was doing the same as yours
I took a flat file, some 320 sand paper and run bottom of the die over the file/sand paper (which was laying flat on the table)
took about .002 -.003 off the die and works great now.
A lathe would have been easier and faster.
With the redding shell holders you have, you should have enough adjustment even if you took .010 off the bottom of the die
Jack

Just lap your shell holder .002 to .003 on a piece of glass as big as a sheet of wet and dry sand paper and leave the die alone. Use WD-40 or any light weight oil on your sand paper while lapping and rotate the shell holder frequently in your grip and keep a light even downward pressure on the shell holder. You can use wet and dry sand paper from 400 grit to 1600 grit for lapping and polishing.

The shell holder below is .003 shorter than the standard .125 and was lapped as described above.

[img width=600 height=450]http://i122.photobucket.com/albums/o254/bigedp51/IMGP6943.jpg[/img]

You have your headspace set so tight your dies are not pushing the shoulder back far enough, you have the longer or taller Redding shell holders which are plus .002 to .010 than the standard .125 (.127 to .135. Now make a shell holder "shorter" (.122) and solve your problem and leave the die alone.
(in the 1970s RCBS told me to do this on a tightly headspaced Mauser .270 made in Czechoslovakia)

If they make taller shell holders "you" can make a shorter shell holder and be good to go. ;)

[img width=600 height=410]http://i122.photobucket.com/albums/o254/bigedp51/7-17-201054345PM.jpg[/img]

I did the same thing with a shell holder for a 6.5 grendel. Couldn't get the shoulder back far enough for a AR build. Hacked up shell holder with a dremel to way more than I needed. Gave me the adjustment I needed So I ordered another one to do a proper job. Way better testing on a four dollar shell holder vs a 200$ set of dies. ;D ;D ;D

If you are not lubing the case neck ID, your neck expander will pull the case shoulder forward giving you the conditions you described. You may want to check this out.

I have already shortened the shell holder from other uses, I guess I could shorten it some more, but at this point I think the body die is going to get shortened.

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If you are not lubing the case neck ID, your neck expander will pull the case shoulder forward giving you the conditions you described. You may want to check this out.

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The Redding Competition dies don't have an expander, oddly enough I don't think you can even put an expander on the neck size die at all.

I have a body die and a neck size die, and of course a seater die.

Body die is fairly cheap, maybe I will call Redding and see if they will send me a new one that has already been shortened.

The Redding body die is a very simple die, just bumps the shoulder and case walls, doesn't touch the neck at all.

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[img width=600 height=410]http://i122.photobucket.com/albums/o254/bigedp51/7-17-201054345PM.jpg[/img]

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I have the set of Competition Shell holders.

I have already shortened my shell holder so the Competition Shell holders don't help at all.

Interestingly enough, I called one of the local gunsmiths and he said the Redding and RCBS dies could be shortened in a lathe.

He also said the Hornady dies are really hard and he wouldn't recommend trying to shorten them.

Since I can drive to his house, maybe I will let him try to take 0.010 or so off the bottom ...

I've had several sets of dies I've had to chuck up in the lathe and remove a few thousands.