Headspacing issue with 5.56, Redding Nat Match dies

[cwsanfor]

I am about to load my first 5.56 rounds and have a case headspacing question.

The cases are from LC M885 fired once in my SIG556. The equipment includes a Lee Turret (Hornady LNL AP and Lee Classic SS available but not being used), Redding National Match Die Set, Hornady Comparator, Giraud Trimmer, and L. E. Wilson case gauge.

I deprimed and tumbled the brass, swaged it in a Dillon D-600 SuperSwage, debarred and uniformed the flash holes and primer pockets, lubed with Imperial Sixing Wax, and sized in the Redding die, measuring the before and after comparator lengths of each case. I then trimmed each case to 1.7523" in the Giraud.

I had previously set up the die to touch the shell plate, then about 1/8th further turn down. The press deflects slightly when I pull the lever, so I have some cam over.

I measured each of 107 cases with the Hornady Comparator, and got an average of 0.0029" shoulder pushback using the Redding Competition Shell Holder (0.006""). Thought I was GTG. Then I got an L. E. Wilson Gauge and all of the case bases I checked protrude slightly (about a rim's width) above the high step of the gauge.

At this point I figure the SIG556 must have larger than usual chamber headspace, and that I need more than .003" shoulder pushback to be within SAAMI spec, so I take some previously sized brass, put in the Redding Shell Holders 0.004", 0.002" and the standard Lee shell holder, increasing the shoulder pushback with each one. None of these resizings caused the case to properly fit the Wilson gauge: it seems I still did not push the shoulders back enough to be within SAAMI standards.

Not sure where to go from here. Options that come to mind include:

1) Lower the Redding sizing die, then see if case sized it it will clear the case gauge,
2) Try the Lee Dies until I can figure out how to set the Reddings,
3) Ignore the case gauge, load and fire these rounds and see what happens,
4) Ignore the SAAMI spec and assume the SIG556 has a very long headspace (same as 3),
5) Something else.

Thanks in advance.

 

[NeuseRvrRat]

did you put a little lube inside the case neck?

 

[cwsanfor]

Yes, I forgot to say, I used graphite to lube interior of case necks.

 

[StandingTall]

nevermind....

 

[MtnCreek]

Check for case head damage that would prevent the case head from fitting into the gauge. Sometimes a overgassed rifle can make some pretty deep extractor marks.

Edit: Take a piece of brass that won't pass the gauge and turn it over to see if it will go in the gauge 'head first'. Don't remember who told be about that, but I do remember I learned it here

 

[cwsanfor]

Cases will go into the gauge backwards, and unfired LC M885 from the same batch are exactly flush with the bottom step of the Wilson gauge, as they should. It seems to be the shoulder stopping the case's forward progress: there seems to be no friction on the case parallel surfaces.

 

[MEHavey]

Having removed the extractor/ejector, does the SIG bolt close on the resized case w/o resistance? (i.e., the real case gauge)

 

[fguffey]

“I had previously set up the die to touch the shell plate, then about 1/8th further turn down. The press deflects slightly when I pull the lever, so I have some cam over”

I notice you have been given some short answers, cause? Could be caused by the responders not understanding the question.


“I measured each of 107 cases with the Lee Comparator, and got an average of 0.029" shoulder pushback using the Redding Competition Shell Holder (0.006""). Thought I was GTG. Then I got an L. E. Wilson Gauge and all of the case bases I checked protrude slightly (about a rim's width) above the high step of the gauge”

After sizing you measured and found the length of the case from the head of the case to its shoulder shortened .029 thousandths,


http://www.hornady.com/store/Lock-N-Load-AP/

The Hornady uses a shell plate, you used a Redding Competition shell holder # 6, I will assume you used the Redding shell holder #6 (+.006) in a single stage press, after sizing you found the cases would not fit in a Wilson case gage, and that is by design, the deck height of the REDDING Competition shell holder #6 prevents the die/ press and shell holder from full length sizing to minimum length + .006 thousandths. The Wilson case gage is capable of producing more accurate readings that the user is able to accomplish, in the instructions L. E. Wilson recommends using a pocket rule, I use a straight edge or a sit up table, when a straight edge is laid across the top of the protruding case head a gap is created between the gage and straight edge, a gap can be measured with a gap gage, thickness gage OR a feeler gage, in thousandths. “I checked protrude slightly (about a rim's width)”, Slightly above or about a rims width? is not a value, Back to the .029 thousands, I am good, with my methods and techniques I can shorten a case for a short chamber .012 thousandths shorter than a minimum length/full length size case. Confusing, you shorten the case when sized using a Redding competition shell holder stamped #6, again, the Redding competition shell holders are designed to prevent excessive sizing, top accomplish this the person operating the press must know one thing, they must know the length of the chamber (or seek and peck), start with .010 and progressively decrease the ability of the shell holder to size as in going from .010 to .008 to .006 to .004 to .002. At some point in the process a case will chamber. For $40.00 that method beats the “adjust the die down until it makes contact then give it an additional 1/4? turn, again, using the Redding Competition shell holder is is going in the opposite direction of giving the die the ‘Ol’ additional preverbal 1/4 turn.

Redding Competition shell holders, not necessary, nice but not necessary, again, I have a #6 set for belted cases, could not afford not to purchase them, at the Big Town Gun Show in Mesquite, TX, $5.00, 3 of the shell holders were off by .001 thousandths each, things like that do not lock me up, think about it, 5 shell holders for $1.00 each, anything that can be accomplished with a Redding Competition shell holder can be with a RCBS shell holder, or a Lee shell holder etc.. Again, it starts with knowing the length of the chamber from the face of the bolt to the shoulder.

You made reference to SAMMI specifications, methods and techniques, I have a chamber, press, dies and shell holders, to make it more clear, I do not load for Sammie’s chamber, I load for my chamber, my opinion, Sammie is a + and or – thing, for self gratification when I finish sizing and or forming cases for a chamber I compare my measurements with Sammie’s specifications. I can not get my chamber measurements to agree with Sammie’s specifications when using dies, shell holders and presses that are adjustable, I have no problem adjusting my dies, shell holders in my presses to size and or form cases for my chambers, again, I have a big advantage, before I start I know the length of MY chamber.


“The cases are from LC M885 fired once in my SIG556. The equipment includes a Lee Turret (Hornady LNL AP and Lee Classic SS available but not being used), Redding National Match Die Set, Hornady Comparator, Giraud Trimmer, and L. E. Wilson case gauge”

Your equipment, impressive, I suggest you attempt sizing cases to fit your chamber, forget Sammie, as we know, Head Space is explained in Lofty Terms, on reloading forms it started that way, nothing has changed, I have a chamber, I have a die and shell holder, I have no control over the length of the chamber, I off set the length of the chamber with the length of the case.

Again, I make datums, I collect datums, I purchase datums, again, I was at the Market Hall Gun show in Dallas, TX, I came to a table and said “DATUMS!!!’ The dealer said he did not have datums, another person looking for a bargion ask “WHERE?!” another ask “What does a datum look like?”

F. Guffey

 

[NeuseRvrRat]

nvm

 

[T Bran]

F. Guffey
That last line was some funny stuff.
We crackers would also be lookin for a recipe for ''DATUMS''.
Our wives would be trying to find you a bride if you used that term in their presence.

All kidding aside thanks for the information on the shell holders I dont have a set but it is nice to understand their intended use.

 

[cwsanfor]

Having removed the extractor/ejector, does the SIG bolt close on the resized case w/o resistance? (i.e., the real case gauge)

I'll try that when I get home. Thanks.

 

[fguffey]

T. Bran, thank you, the person that wanted to know what a datum looked like was the only person I could help.

“I don't have a set but it is nice to understand their intended use”

Exactly, to understand the intended use is to understand they are nice but not necessary, The Redding Competition Shell holder offers 5 options between minimum length/full length sized and +.010 thousands (.001 thousands longer than a no go-gage for a 30/06). I have 10 choices between minimum length/full length sized, again, my dies and presses have threads, threads make my dies adjustable, I choose to verify the adjustment.

F. Guffey

 

[fguffey]

Cwsanfor, back to “Where to start”, you state the “The cases are from LC M885 fired once in my SIG556” you fired LC cases in your STG556, you have a lee comparator. I will assume the case length was not measured fro, the case head to the shoulder before firing, my opinion, that is a bad habit, but measuring the length of the case after firing puts you into step with most if not all members on this forum (except me), not a problem, but if you had measured the length of the fired case from the head of the case to the shoulder of the case you would know the length of the chamber from the bolt face to the shoulder of the chamber, and that is the confusing part, you choose to use a Dillon competition shell holder to size a case for a chamber you do not know the length from the bolt face to the shoulder of the chamber.

Removing the extractor? Cases are considered solid, head space gages are considered solid, I do not have a rifle that has an extractor that interferes with the bolt closing when a case and or gage is in the chamber, I do have a few friends that do not understand the difference between control feed and push feed, seems there is another type feed I do not understand that would best be described as ‘forced feed’.

You have said nothing about seating bullets, I am the fan of bullet hold, others talk about neck tension, most failure to feed is caused by not adjusting the crimp portion of the die off to avoid crimping, too much crimp can caused the neck to loose bullet hold (reduce neck tension?) and collapse the case at the shoulder.

My opinion, you need standards, nothing like a box of new ammo for your rifle, you are not required to shoot the new ammo, but, if the new ammo chambers and allows the bolt to close (without removing the extractor) and fires before the case can out run the primer strike you are well on your way to solving your problems (NOTE! Do not shoot all the new ammo, same a few for reference) and when you extract the fired cases you can measure the length of the case from the head of the case to its shoulder to determine the length of the chamber.

DIFICULT PART: Deciding, once you know the length of the chamber you have to decide if the information is nice to know or very important to know, if it is important to know you will have to decide how you are going to transfer the information from the fired case to the press, die and shell holder. Again, I am the fan of transfers, standards and verifying, I make an adjustment, I verify.

F. Guffey

 

[Walkalong]

If you are sure about your pushing the shoulder back about .003, you will be fine as long as the loaded rounds are shot in the Sig, but if they get in an AR or another Sig with a proper chamber, it could lock them up pretty good.

If you are not pulling the shoulder forward with the expander plug, you have pushed the shoulder back .003, and the case shoulder holds the case a rims thickness out of the case gauge, i would have the gun checked for excessive head space.

Sure, if we have a gun with excessive head space by SAMMI standards, we can form the brass to fit the chamber and be perfectly safe, but those rounds will most likely work only in that gun.

1) Lower the Redding sizing die, then see if case sized it it will clear the case gauge,

Might work, but a rims thickness out of the gauge? Watch out for case head separation if you are really moving the shoulder that much.

2) Try the Lee Dies until I can figure out how to set the Reddings,

Why?

3) Ignore the case gauge, load and fire these rounds and see what happens,

If they will chamber freely, why not?

4) Ignore the SAAMI spec and assume the SIG556 has a very long headspace (same as 3),

1.Make sure your measurements are correct, and you are not pulling the shoulder forward with the expander plug.
2. Get a gunsmith to check the rifles head space, or buy go/no go gauges and check it yourself.

 

[hentown]

I'd forget about reloading for a while and concentrate on doing something about that acute OCD!!~!

 

[fguffey]

“I had previously set up the die to touch the shell plate, then about 1/8th further turn down. The press deflects slightly when I pull the lever, so I have some cam over”

Or the case is whipping the press, I still do not know what press you are using, meaning I do not know if your press is a cam over press, some jam over, cram over or just lock-up. All of my Rock Chucker presses jam, cram or lock up, all of my Herters cam over.

Hentown, I will stand by my response, most did not understand the question(s).

Pulling the sizer ball/button back through the neck when lowering the ram pulls the shoulder forward?? I have heard that for years, it does not happen, boils down to measuring before and again after, not complicated but it can be done, on the outside chance there are those that do not agree call Redding, tell them their National Match dies for $140.00+ dollars is stretching the case by pulling the shoulder forward when the sizer button is pulled the neck. There answer, in all likelihood, will sound something like “We have not found that to be true” or “We have found that to be untrue”.

Then it goes back to the Hornady size plug and friends telling me “They just have to have on of those sizer plugs for their RCBS dies” then I update them on a cut-off date, sizer plugs were changed to a new design, dies made after a certain date came with the new designed sizer plug.

1 800 533 5000, free Special Order Catalog, the Catalog list cases that can be formed with a Full length sizer die that has the correct neck sizer button, and then they list the date of change, older dies can be updated for forming if the sizer button is changed.

F. Guffey

 

[fguffey]

If Cwsanfor has fired his ammo in his rifle he has fired cases, with all the equipment he claims to have there is no reason for him to do anything but measure the length of the case from the shoulder/datum to the head of the case, then figure a way to transfer that measurement from his gage to the press. Again, he is talking about a Redding Match set of dies, the perfect transfer tool for the Redding Match sizer die is the feeler gage. The feeler gage beats “about” every time.

F. Guffey

 

[StandingTall]

....I still do not know what press you are using...

From the OP:

"The equipment includes a Lee Turret (Hornady LNL AP and Lee Classic SS available but not being used)"

 

[fguffey]

Again, I do not believe the question is understood, let us pretend I know nothing about presses,


Quote:
Originally Posted by fguffey
....I still do not know what press you are using...

From the OP:

"The equipment includes a Lee Turret (Hornady LNL AP and Lee Classic SS available but not being used)"

He also says:

“I had previously set up the die to touch the shell plate, then about 1/8th further turn down. The press deflects slightly when I pull the lever, so I have some cam over”

And then he claims to be using a Redding +.006" shell holder, so I ask you, Is there a press that uses shell plates and shell holders?

I do not find it necessary to use redding Competition shell holders, but if I did, I would find using the Dillon Competition shell holder would reduces the strain on the press and as a results there would be less deflection.

Again, I have strain gages, I have deflection gages, I have tools that convert strain to torque.

I have shell holders, one is a set of 5 from Redding, the set I have is the #6 set for belted magnums, $5.00, after checking the deck height I found 3 were .001 thousandths off, with the Redding shell holders I have 5 options, before I purchases the Redding Competition shell holders I had 10 options when adjusting the die.

F. Guffey