How do you fix .308 brass headspacing incorrectly?

[Tomas]

I am a pretty experienced reloader, but still humbled by my inability to get reloads to reliably feed in both my M1A and my DPMS AP4.

A recent thread in the "Art of the Rifle" finally answered the question I have never been able to solve. In my M1A I was having the bolt come back most of the way during recoil, but not far enough to eject the brass. For the longest time I though I didn't have the proper powder and thus not enough gas pressure to fully operate the gas system, but couldn't get over the fact that 43 gr of 748, or Varget or 760 or whatever I used at the time wouldn't work the action. I gave up and stuck to milsurp.

After buying the AP4 in July 09 (7.62x51 chamber), I tried again to feed it reloads. This time, I began having problems with it going full auto (primers not seated deeply enough - easy fix) and the bolt not fully closing on the cartridge and basically having to pry it back with a screwdriver, because you sure as hell couldn't pull it back using the charging handle.

After some further research, both issues turn out to be from improper headspacing. So, I go buy a Dillon .308 headspacing/OAL gauge and probably 70% of my LC brass is jacked, it's too long.

I trim all my brass to 2.0" and full length resize after each firing. I use Lee dies.

Is there a way or different die I can get to fix this brass? It still works just fine in my Weatherby .308, so I can always use it for that, but I bought it so I could feed it through my Obama rifles (semis).

Your wisdom and experience is appreciated.

Tom

[kraigwy]

Do you use a Case Headspace gage to set up your sizing die. You're problem sounds like excessive headspane (case not gun) meaning its too long between the base and the shoulder.

A simple check with a case head space gage to check your brass will tell you one way or the other.

[Mark whiz]

I started out with a set of Lee .308 dies and found I really wasn't happy with them for my M1A either. I bought a RCBS Precision Mic to check my case headspacing and found that it often took 2 or 3 runs thru the die to get the case headspace to where it needed to be. I switched to a Forster Bench Rest die set and found it to eliminate 95% of the short-spaced cases.
I size my brass about .002" shorter than the chamber headspace measurement given me with the rifle - so I usually mic all my cases after sizing JUST to make sure none are too long (a BIG bad issue with M1A reloading) and out of 50 shells, maybe 2 or 3 have to be run thru the die again to make sure they are sized down to where I want them.

Oh, btw, when using mil-spec brass like LC - knocking them shoulders down is even harder than with commercial brass.................using a firm hand on a strong press helps.................but be diligent on checking the headspacing on the cases and in time you will develop a "feel" for when something may not be quite right.

[HiBC]

Mark,Redding offers a set of shellholders that are incrementally stepped in height.They give you something better than crunching harder.
I am not an expert on service rifles,but I have read Precision Shooting"s Reloading guide.They discuss reloading for Service rifle competition at length.The headspace spec they strongly recomended for M!A's and the like was .006
This is a good,valuable book and covers methods of efficiently producing match ammo.

[tomj44]

Go here http://m14tfl.com/upload/ for reloading and other M1a info.

[Unclenick]

HiBC,

I believe the Redding shell holders are to limit resizing? In other words, they are only oversize to make cases longer, not shorter. It seems to me I looked up a kit of them once and they were all +numbers over standard.


Tomas,

Special dies called small base dies are made to overcome the problem you mention. Both Redding and RCBS .308 small base dies are cataloged on Midwayusa.com. If you know someone with a lathe and tool post grinder, you can also have the mouth of the Lee die ground back a few thousandths if it is too long for your gun? That is not uncommon to have to do for self-loaders.

Other thoughts and tricks:

Is your die setup correctly? That is, have you put a lubricated case in and pushed it all the way up and checked with a flashlight behind the die and shell holder that there is no crack of light at all coming through between the two? If there is, screw the sizing die in further.

The same guy with the lathe or a guy with a surface grinder can also thin the top of your shell holder by however many thousandths you need to get you what HiBC was hoping the Redding shell holders would get you. If you are good with tools and are patient, you can do it yourself by gluing some wet-dry sandpaper (say, 120 grit) to a piece of plate glass with spray adhesive, then pushing the top of the shell holder back and forth across it, rotating a little every few strokes to keep the cutting even and using water as a lubricant. You periodically rinse it and measure the height until you have the reduction you want and to check for and correct any unevenness.

It can also be the case that another brand standard sizing die will work where the Lee does not. Lee makes good dies, but one that narrows the case more than another will squeeze the shoulder further forward, too, before the die shoulder is encountered.

Mark Whiz mentioned multiple resizing. The brass will actually relax a bit if you give it time. Run the case up into the die and keep it there while you count to five. Back it out, turn it 180 degrees and repeat. That will usually get you another two or three thousandths of extra shoulder setback.

Anneal your case necks. The brass work hardens over repeated sizing and that makes it more springy. If you anneal the necks and shoulders the sizing die will have an easier time setting them back and they won't spring back as much after leaving the die.

[bigalshootmupper]

I reload for the DPMS LR-308 and I use the RCBS Precision Mic to check the headspace and it works. But you don't need it. After you resize and retrim your brass(in that order), put it into the chamber and slowly push the bolt closed. If it won't close without a lot of pressure, then it is sized with too much distance between shoulder and bolt face. What I did was start out with sizer die just touching shell holder and check each sized case in chamber (trim to spec after each sizing). I kept tightening the die down to shellholder until the bolat would close on a sized case without a lot pf pressure. I then tightened the die a little more (maybe a 1/4-1/2 turn) until the sized case plus a piece of paper between bolt and case would close. This is perfect size so for reliablility and case life.

[F. Guffey]

The Redding shell holder set is + or -, the shell holders will reduce the case length from the case head to the shoulder or prevent the case length from being shorten by increasing the deck height, 5 shell holder set from Redding, -$50.00 plus shipping, a feeler gage $11.00, Shell holders are case head specific, feeler gage, one set fits all, 10 sets of Redding shell holders $500.00, feeler gage $11.00.

I have an in-line butt and angle grinder, it would be a matter of chucking and or clamping, zero, turn on the coolant and grind, I do not load for one chamber, I had rather adjust the die than compromise the integrity/dignity of the shell holder or die.

RCBS will custom grind a die for $50.00 + or - a few, feeler gage $11.00, (custom grind a die for a short chamber).

The deck height of the Redding custom shell holders is .000 + or -.

F, Guffey

[FrankenMauser]

Buy a better sizing die. Your Lee die is over-sized, and worthless without modification.