Shoulder won't set back

[119er]

I am loading Lake City 7.62 brass that was bought new and is now once fired by me in a new M1A. I can't get the stripped bolt to close on the resized case and I have the die (RCBS small base .308) adjusted to the point of significant cam-over. The lowest headspace measurement I can get is 1.626" The brass as new measured 1.622" and passed the bolt test with no problem. Springfield includes a card with the factory set headspace and it claims 1.632". I reassembled the rifle and allowed full bolt thrust to chamber a case measuring 1.630" and when I ejected and measured the case it was 1.622"

Any suggestions as to what's going on?

 

[119er]

Problem was gone after switching to my single stage press. Maybe too much resistance causing flex with the progressive (LNL AP)? Still seems weird that a 1.632" chamber requires the case sized to 1.624" to chamber freely. The .003"-.005" rule would have let me down here unless there is something I'm missing. BTW the fired cases measure 1.630" which is shorter than the what the chamber supposedly is. Using that measurement .005" is close but 1.624" has a slight drag.

Anyone use their chamber to final size? (jk)

 

[Walkalong]

adjusted to the point of significant cam-over.

Did you check cam over while sizing, or with no case. It needs to be checked while actually sizing a case to take press flex into account.

Presses look sturdier than that, but they certainly do flex.

 

[W.E.G.]

The brass as new measured 1.622"

That is extremely unlikely.

You need to enlist somebody to assist you in making correct measurements.

As for not being able to push the shoulder back, have you checked to see whether you have your expander/decapper assembly installed so low, that it is impeding the shell casing from going to the top of the ram stroke?

 

[GP100man]

Press flex will make ya scratch ya head fer shore !!

This is what I ran into on a single stage with some milsurp brass .
I started out with a Lee shell holder bumping the die under stress of resizing .

Would`nt chamber (luckily I was anxious to try the milsurp brass & only loaded 10 rnds. !) shoulder spring back ???setback ?? .Found it by blackening a case with magic marker , not setback quite far enuff ???

Found the shellholder was .015 thicker from where the case sat in it to the top rim that bumps the die , an RCBS holder fixed it . I was using RCBS dies , so mixing tool brands is`nt always OK especially dies & shell holders .

 

[Slamfire]

Sometimes the die is too long. I have had that particularly with Lee Sizing dies in foreign calibers. The fix was to grind material off the bottom of the die till the shoulder was set back correctly.

As for your measurements, I have no idea what measuring devices you are using, but you should be using something like a Wilson gage as those are dimensionally correct.

"Comparometers" give weird results and I don't trust them.

 

[119er]

Good suggestion WEG despite your snide comment about my measuring abilities, but no. I can add pictures if you like. Perhaps you didn't understand that this is a headspace dimension taken via comparator bushing?

I'm guessing it had to do with the shell plate dimensions vs. the standard shell holder. It may be fixed by removing material from the base of the die as suggested. I'll probably replace these dies with the Redding National Match dies. I use the .30-06 ones for my M1 and love 'em.

 

[918v]

Oh the joys of Obamaloading.

I think you would just love a set of Redding competition shell holders. They allow you to bump the shoulder back in .002" increments when you set your single stage press to cam over. I usually see an interference fit with the +.008" shell holder and go with the +.006" one. Treat yourself. It's Chrismas!

 

[119er]

Thankfully I'm not part of the panic this go 'round. Learned my lesson in '08! I will certainly check out the competition holders.

 

[Kp321]

I cringe when I see someone recommend grinding dies to shorten. Always grind on the cheap part, the shell holder in this instance. (Unless you have a progressive).

 

[Walkalong]

If you grind the shell holder, it will affect any die used with it. Mark it for future reference.

I would rather modify the die, but before modifying dies, we need to be 110% sure it needs it.

 

[918v]

I did that with my 9mm shell holder to get the cases sized right. RCBS shell holders are case hardened and difficult to mod. Use power tools to get through that hard layer. If you can chuck it in a drill somehow, maybe by running a bolt through the center and spin it while grinding with a dremel or die grinder then you can get an even level surface. I did it using a belt sander and spun the shell holder with my fingers, then finished with a file. It was painful.

 

[ranger335v]

Everyone to his own methods and it means nothing to me but I can't get my mind wrapped around the idea of modifying a shell holder to correct for a die problem. ??

 

[GP100man]

Yep ,me to . If the die was cut kinda deep first I`d contact the manufacturer .

If no joy ,then I`d trimm the die.

Luckily a shell holder remedied mine .

I`m bad for buying cheap machine gun 30-06 brass, but it works good once ya get it back into shape .

 

[popper]

I use my rifle to set HS and then adjust the die to fit. If it needs grinding, do it.

 

[243winxb]

"Weird that a 1.632" chamber requires the case sized to be1.624" to chamber freely.

I reassembled the rifle and allowed full bolt thrust to chamber a case measuring 1.630" and when I ejected and measured the case it was 1.622"

The 1.622" is the comparator number you should work with. The rifle has set it for you. Dont try to match camparator readings with Springfields 1.632"

Problem was gone after switching to my single stage press.

If not flex, shell plates can be to thick or thin. All plates/shell holders should measure .125" +/- .001" for correct sizing. Just how i see it.

 

[Faret]

^+1

 

[918v]

Everyone to his own methods and it means nothing to me but I can't get my mind wrapped around the idea of modifying a shell holder to correct for a die problem. ??

Some people need a quick fix using tools they have on hand. Cutting the shell holder is less expensive than cutting the die. It is not the best solution, but it is the cheapest and safest one.

 

[thump_rrr]

My guess is he is using a Hornady comparator.
My Hornady comparator also gives me a similarly low number on my Savage .308. My only .308 for that matter.
When a fired case is set in my Dillon case gauge it actually is within spec so my assumption is that the hole diameter on the Hornady comparator is not within spec therefore not measuring exactly at the datum line.

 

[ranger335v]

"Some people need a quick fix using tools they have on hand. Cutting the shell holder is less expensive than cutting the die. It is not the best solution, but it is the cheapest and safest one. "


I suppose all of us need to use the tools we have at hand but I disagree that it's easier to work on a shellholder than a die and can see absolutely no difference in the 'safety' of either approach.

Both shellholders and sizers are case hardened so both will need to be ground, either with a grinder or by sanding. The bottom of a die has much less metal to remove than the top of a shellholder and it will be much more difficult to keep the top of a shellholder even while it's not hard to keep the bottom of a die square for the tiny amount of metal that would need to be removed.

 

[918v]

A shellholder can be replaced for what $5? You are suggesting cutting on a die using hand tools? And what do you do if you screw it up?

 

[W.E.G.]

Good suggestion WEG despite your snide comment about my measuring abilities, but no. I can add pictures if you like. Perhaps you didn't understand that this is a headspace dimension taken via comparator bushing?

If you are interested, you can PM me for my address, and you can mail me several pieces of your 1.622 brass.

I will measure them and tell you what is the actual dimension of them.

A $5.15 Priority Mail shipping box might be cheaper than a set of dies, and more effective than guesswork of picking different manufacturer's shellholders out of a hat.