Resizing Lake City 5.56mm Brass

[Lone_Gunman]

I am working on resizing a large amount of LC 5.56mm brass. This was shot out of both M4s and SAW rifles.

I have used both a standard Lee 223 sizing die, as well as RCBS small base die. I am using a Lee shell holder for both.

I am resizing on a single stage press. I screw the die in until it hits the shell holder, then screw in half a turn more so I can over cam a little.

After I resize the case, I drop it into a Lyman case gauge. About 20% of the time, no matter which dies I am using, I get a case that sticks out of the case gauge by a tiny amount, I would say 1 millimeter. Sometimes if I push just a little, the case will go ahead and seat flush in the case gauge. I am rejecting all brass that will not seat flush into the Lyman case gauge.

Also, I have noticed that about 10% of the cases don't want to slide easily into the shellholder on the press. I have tried this with two different Lee shellholders, and get the same problem. I cannot see a defect in the case head that would explain why they won't slide easily into the shellholder. The brass that has a hard time sliding into the shellholder easily is the brass most likely not to fit into the case gauge after resizing.

Questions:

Why won't all the brass easily slip inot the shell holder?
Why does some of the brass not get sized small enough to drop into the Lyman case gauge?
Is this related to the type of weapon the case was originally fired in (ie, a machine gun with a looser chamber)?
If the resized case does not fit easily into the Lyman case gauge, should I reject it? Is there some way to still salvage it?
Should I also discard the brass that will fit into the case gauge with a little push?
Do I need to use a RCBS shell holder with the RCBS small base die sizer? Or is the Lee shell holder OK to use with it also? Will a RCBS shellholder fit into the ram of my Lee single stage press?

 

[Borg]

Stick the head of the case in the gage first,, if it don't fit, the casehead may be out of spec. Not muchyou can do about that, however, check to see if the case chambers in your rifle.
If it does fit in the gage, then use a little lube INSIDE the neck to ease the expander back through the case neck to keep it from stretching the shoulder out creating a longer headspace.
Borg

 

[rfwobbly]

LG -

1) Sometimes "machine gun" ammo is more powerful than regular rifle ammo, even for the same caliber. If the SAW ammo was loaded to the max or to some sort of "+P" type load, then the base & rim area of the case might also expand. Or maybe the chamber of the SAW is "unsupported" like some Glock chambers. If this is the case, then you need to measure the base of the case very carefully. It's no good reloading this ammo since it may never fit into your rifle's chamber with an expanded base/rim area. It will chamber all but the last 1/4 inch and then jam. Not a fun thing to deal with at the range. A full-length cartridge gauge might be helpful.

2) All "bottle neck" rifle brass grows in length during the resizing. The brass actually flows from the base out toward the neck. Consequently, the length of every rifle cartridge needs to be measured after sizing, and "trimmed". This operation is performed with a "case trimmer". If you reload a lot of cases, this can get to be a headache really fast.

I've found that military 5.56 with crimp tends to be on the long side when using the SAAMI reloading numbers for .223, so the first time out you may have to trim off .020" or more.

Trimmers come in all shapes and sizes. First thing you need to decide is how do I want to power this trimmer: by hand or by motor. That will cut your choices in half and make things somewhat easier.

I use a 30 yo Lyman unit that has the optional carbide cutter. The crank handle has been removed and an adapter put on the shaft so that I can power it with my drill motor. This is a common home up-grade you may wish to investigate.

* There is one way around this, and that is to use the RCBS X-Die system. When using X-Dies, the first trim is big, but the dies cut the rate of growth after that, which negates all the subsequent trimming.

Hope this helps!

 

[Lone_Gunman]

It will chamber all but the last 1/4 inch and then jam. Not a fun thing to deal with at the range. A full-length cartridge gauge might be helpful.

I am using a full length case gauge by Lyman. For the brass that fails to size correctly, the case head sticks out of the gauge by about 1mm, not a quarter of an inch. So I am coming pretty close to getting it completely resized, just not all the way.

I do my trimming with a Giraud trimmer, but that is another step down the road. Right now I am just trying to get the case back into correct spec, I will trim afterwards.

 

[rcmodel]

then use a little lube INSIDE the neck to ease the expander back through the case neck to keep it from stretching the shoulder out creating a longer headspace.

+1

That right there might be your problem.

Dab the case neck on a lube pad and it will pick up enough lube to do the trick.

Personally, I use case lube spray on a nylon bore brush to clean / lube all the case necks before sizing.

Your Lee shell holder might be just a scooch under size.
Using a Dremel point and polishing the lip a little to get rid of any burrs or roughness might help.

rc

 

[Lone_Gunman]

Personally, I use case lube spray on a nylon bore brush to clean / lube all the case necks before sizing.

I have got some Hornady One Shot, can I just spray a little of that across the case mouths?

 

[Lone_Gunman]

I just did a little testing...

The case heads of some of the unsized LC brass are too big around to fit in the case guage when I try to insert them backwards into the gauge.

These are the ones that cannot be sized properly.

What would make the caseheads of these rounds be too big? Is it the gun it was fired in previously?

 

[rcmodel]

Probably machingun with a very loose chamber. In which case a small base die might help, or not.

A light spray of lube across the mouths is plenty. Don't get a bunch of it inside the cases.

I spray lube mine in a mixing bowl. There are enough of them pointing up for some to get a little lube in the necks. Every one doesn't have to be lubed as the expander button will carry excess from one case to the next.

rc

 

[Lone_Gunman]

A small base die won't size the part of the case head that is inside the shell holder, and this is the part that is too big. In fact, some of these are so big I can't even put the case in the shell holder.

I don't understand why this part of the case head, ie, the part with the LC marking on it, would expand upon being fired.

 

[rcmodel]

High pressure for whatever reason.

*Very hot machinegun barrel?
*Very hot day cooked the ammo in the can before it was fired?
*Ammo was at the upper end of pressure specs to start with?
*Cases were at the upper end of size specs to start with?

Any number of reasons.

Case head expansion is an indication the brass has begun to flow due to exceeding it's modulus of elasticity or yield strength. (plastic deformation).

rc

 

[Lone_Gunman]

OK, thanks for the help. I guess if the case head is too big to fit in the shellholder, that piece of brass is just scrap now.

 

[Slamfire]

A small base die won't size the part of the case head that is inside the shell holder, and this is the part that is too big. In fact, some of these are so big I can't even put the case in the shell holder.

I don't understand why this part of the case head, ie, the part with the LC marking on it, would expand upon being fired.

You are limited by the tools available.

I understand commerical reloaders have machines that completely size the case.

Your ammo must have been fired in a chamber with a huge chamber, maybe unlock occurred when there was a lot of pressure in the chamber.

Cases are simply a gas seal. Yours sealed the chamber, but it was a big chamber.

 

[rcmodel]

Even if it does fit, you probably will find they have loose primer pockets too.

Unless of course, they were just out of spec brass and made that way.

rc

 

[GRIZ22]

Sometimes "machine gun" ammo is more powerful than regular rifle ammo, even for the same caliber.

A SAW uses the same ammo as a M16 or M4 not "machine gun ammo". The SAW may have a looser chamber which would let the brass expand more but I can't say this for sure.

 

[Walkalong]

When the loaded rounds "jam" with the last 1/4" stuck out of the chamber, it is not necessarily the case head area that is over spec. It is usually the front part of the case/shoulder jamming things up. Did you gauge the loaded rounds?

The only ones I have ever had a problem with was where I crushed the shoulder ever so slightly by over crimping. They would still chamber in some guns, but not a tighter chamber like some guns have. My Mini 14 would gobble them up and spit them out. It's not very picky, and obviously has a generous chamber.

My cheapo Model One Sales uppers Mil Spec Chrome chamber will accept them no problem as well. I had a RRA with a Wylde chamber that would lock up with a round like this. It would stop short of chambering completely and jam up right nicely.

 

[counterclockwise]

Good advice from all. I wanted to add that a while back I was sold a Lee case holder to go with my RCBS die and Turret Press since the vendor was out of RCBS holders. The Lee and RCBS did not work well together. I got an RCBS #10 shell holder to match up with the RCBS die and press and things seemed to go better.

Casings that have expanded much over .001 on the diameter, measured at any point along from casing head flange to .200 above the casing head flange are candidates for the scrap barrel, because 1. it can be an indication of the casing being over stressed, and 2. since the head has permanently expanded, the primer cup ID has permanently expanded as well resulting in the potential for loose primers. Spent primer cups falling out into the action after firing, may not be a big deal with bolt guns, but can wreak havoc with autoloaders.

 

[243winxb]

I guess if the case head is too big to fit in the shellholder, that piece of brass is just scrap now.

Sounds good to me. http://www.thehighroad.org/showpost.php?p=5463959&postcount=6

 

[Lone_Gunman]

I am not sure how those photos would apply to my situation.

 

[Walkalong]

Never mind I see now. duh on me.

 

[243winxb]

Expanded Web Area or Primer Pocket

I don't understand why this part of the case head, ie, the part with the LC marking on it, would expand upon being fired.

Lone Gunman, Proof rounds like M197 HPT that are at 70,000 PSI will have the web area near the head rim area expanded from firing. Normal resizing that we do will not touch the expanded area. Special Roll Sizing is needed to bring the brass back to factory specs. Some would say this process can weaken surplus brass, LC. When any brass expands in the web area as some of yours has, it should be discarded as scrap IMO. But bench rest shooters make special dies to resize the web area for extra firing. They are using minimual specification chambers and this does not apply here. The 2 photos where the web area has opened up is from defective brass or brass that has been roll sized IMO.http://www.inetres.com/gp/military/infantry/rifle/556mm_ammo.html Plus what RCModel said in post #10

 

[Sport45]

OK, thanks for the help. I guess if the case head is too big to fit in the shellholder, that piece of brass is just scrap now.

Not always. Is the case head really too big? Sometimes it's just an extractor burr on the rim that keeps the case from dropping cleanly into the gauge. I keep a needle file on the workbench. I can usually find the burr and file it off or just make a quick pass around the rim with the file and find they'll gauge just fine. Don't file on the case itself, just the rim.

 

[243winxb]

Sport45 made a good point, sometimes its just that simple, its a burr

 

[Lone_Gunman]

I have looked closely, and I see no burrs. Case head is just too big to fit in the gauge.

 

[Borg]

Have you tried seating a primer in them?
If they seat with resistance, it could be just out of spec brass,, does it have the nato cross on it?
If not, then it was probably too far out from mil specs.
'Borg