Excessive headspace question

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kuca_2004

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I am reloading for a 6.5 creedmoor. The rifle is a semi auto DPMS. I just bought some of the non-adjustable L.E. Wilson case gauges. The head of the case sticks out so my headspace is not right. How do I fix it? I have had problems with cases getting stuck in the gun. I have the RCBS small base die set.
 
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I believe that head space is measured off the shoulder. If your brass is protruding above the case gauge then your brass could be too long. What is the length of your resized brass?
 
The head of the case sticks out so my headspace is not right.
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it is neather right or wrong.

Your Wilson gage is a case gage, it is not a head space gage. Then to finish it off the case does not have head space.

If the case protrudes from the Wilson case gage you need to determine by how much. I use a straight edge and feeler gage to determine how much case head protrusion I have. The Wilson case gage is a datum based tool.

It would help if you learn to measure the length of the case from the shoulder to the case head before firing. In the perfect worl and if you were measuring new, factory cases in the Wilson case gage the case head would be .005” below the top of the case, after firing and in the same perfect world the case head should be level with the top of the gage. Problem; reloaders assume their chamber is perfect.

You do not know the length of the case before firing meaning you do not know what effect the chamber had on the case when fired. You have a small base die, I have small base dies, I do not use them but I have them just in case.

I suggest you reduce the length of the case from the shoulder to the case head by .004” with a full length sizing die and start over.

F. Guffey
 
Kucka 2004,

Do the cases get stuck before firing, so they can't be ejected unfired, or are they stuck after firing? Stuck after firing is a high pressure sign.

If they are getting stuck before firing or during loading, then you are not resizing the cases enough to fit your gun.

So my first question is, do cases from new commercial ammunition that are fired in your gun fit the Wilson gauge before you resize them? In other words, are they sticking out more after resizing than the do before resizing? If so, it means the die is not pressing against the shell holder hard enough during resizing. I say this because with most bottleneck rifle cartridges, there is contact made with the sides of the case and die first. This narrows and lengthens the case. Only after the die shoulder makes contact with the case shoulder does it start to move the shoulder back and flow the excess brass into the neck, which is what grows the case.

Improper sizing die is common among folks new to reloading (I don't know if you are). What happens is the sizing force stretches the press slightly. As a result, even though the die was in contact with the shell holder when you set it up, when you actually have a case in it and forced up to maximum a crack of light can be seen between the case mouth and the top deck of the shell holder. To prevent this you have to compensate by turning the die down a little at a time until it disappears. Usually a quarter turn beyond contact will do it for a heavy cast iron press. With an aluminum press like some of the Lee presses, it's modulus of elasticity is lower, so it stretches more easily, and you may need as much as 3/4 turn extra.

Lee's help video on setting up a sizing die shows how to do this for an aluminum press and how to check for the crack of light. For an iron press, just figure about 1/3 as much extra turn after finding the contact point.

If you want, you can also try Mr. Guffey's trick of removing your decapper and sliding a feeler gauge into the shell holder under the head of the case. This will cause it to be resized further by the thickness of the feeler gauge. You will, however, have to return the expander and run the case over just that part as a second operation afterward, or the neck will come out too narrow, making bullets harder to seat straight.

Shoulder%20Setback%20and%20Growth%20II_zpsvgwe5rip.jpg
 
The difficult part is how to uee the Wilson case gage to measure the length of the case from the shoulder to the case head. From the beginning Wilson recommended the reloader us a straight edge; that was in 1955 +/- a few years.

If the case is protruding from the gage stand the case up on a flat surface then place the gage over the case. The gage will be supported by the case; what does that mean? The reloader with the companion tool to the press, the feeler gage can measure the length of the case if they understand the Wilson case gage is a datum based tool and the gap created is to be added to a go-gage length gage.

No, it is not necessary to own a go-gage. This is all about getting to know your Wilson case length gage and the datum. Again, I use a straight edge and a feeler gage, I can also use a height gage and I can use a dial caliper because one end of the dial caliper is a height gage.

F. Guffey
 
Let's go back to the basic question: Does the case stick before -- or after, firing?
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We could do that but first you have to ignore all the information furnished.

The head of the case sticks out so my headspace is not right. How do I fix it?
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He has a small base die, I believe he would be better off with a full length sizing die and I believe he should learn to use it.

F. Guffey
 
I am reloading for a 6.5 creedmoor. The rifle is a semi auto DPMS. I just bought some of the non-adjustable L.E. Wilson case gauges. The head of the case sticks out so my headspace is not right. How do I fix it? I have had problems with cases getting stuck in the gun. I have the RCBS small base die set.
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I assume you are measuring fired cases. Is that a good guess? You cannot measure fired cases out of a semi auto and get the chamber headspace. Gas guns open up when there is pressure in the barrel. Given a dry case fired in a dry chamber, your case is adhering to the chamber walls when the mechanism starts to unlock. The consequence is that your case will be stretched on extraction. Now I lubricated my 308 and 30-06 cases in my Garands and M1a's, to prevent case head stretch. And even though lubricating the cases prevented sidewall stretch and subsequent case head separations, fired cartridge headspace was not chamber headspace. The cases were still too long. Even with oiled cases, during extraction the case shoulders were moving forward, due to the residual pressures in the barrel, shaping themselves to the chamber shoulders during extraction.

So set up your dies to size your cases to gage minimum. Ignore the length of a fired case as using fired cases to determine chamber headspace only works on single shots and bolt rifles.

If you were sizing your cases based on the length after firing, your cases would be sized way too long. This would result in a crush fit, your mechanism would be crushing the case into the chamber during cam down. While that would be dangerous in a Garand type mechanism, (due to firing pin bounce), in your gun, all it will result in is jams and failures to extract. You crush fit a case in this mechanism, the case to chamber friction and lack of clearance between the case and chamber will result in a failure to extract.
 
Now I lubricated my 308 and 30-06 cases in my Garands and M1a's,...
Oh dear.
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Awaiting the flood, I am....
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Perhaps this will head off the misconceptions about lubricated cases, there are plenty of historical examples of weapons using oiled and greased ammunition in world wide conditions.

This is an oiler on top of a Schwarzlose machine gun. The cap covers the reservoir which is filled with oil.



This Japanese Nambu used an oiler. This oil tank is next to the cartridge hopper.







And the 20mm Oerlikon used greased ammunition. The 20mm ammunition was greased prior to linking. This weapon was used on everything during WW2. Greased ammunition was fired from this machine cannon from airplanes, boats, trucks, ships, you name it. This weapon system was used up the Vietnam War.

 
Ok.... Cartridge headspace dimension too long for the chamber.

Level-1 question: Are you camming-over on the full-length resize stroke?
 
kuca 2004, I never used a small base die, I'm sure though the reloading process is the same. From start to finish. Clean fired cases, measure headspace from base to datum, F/L size to give .002 from fired case, measure case OAL from base to end of neck, trim back if needed. I trim every firing to .003 back from max. Chamfer inside & out case neck. I wouldn't crimp. Seating, do you know where your rifling starts? I think either your cases are to long or your bullets are seated to long, jamming in your chamber
 
Is the cam over with contact between the die and shell holder ( are they touching when press cams over )

Are these completed rounds or just the sized cases that don't fit the gauge ?

What dies and shell holder ?

Are you crimping ?
 
Level-1 question: Are you camming-over on the full-length resize stroke?
Yes I am.
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Let's go back to the basic question
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or the basics of reloading.

I do not know what press you are using. I have 11+ presses that are the same color that cam over. I have 5+ presses that are green and from RCBS that do not cam over. None of my RCBS presses cam over.

Back to the fundaments of reloading; the case has resistance to sizing; the press has an ability to overcome the cases ability to resist sizing. When the press fails it is an acceptable practice to adjust the die down an additional ¼ turn or .017”. If the die was adjusted an additional ¼ turn after shell holder contact and the reloader adds an additional ¼ turn the die has been lowered .035”+ after contact.

There comes a time a reloader should be able to determine if the case won or the press won. When my cases have more resistance to sizing than one of my presses can overcome I check the gap between the shell holder and bottom of the die. The gap will indicate the amount of the case that did not get shoved into the die.

And then there is case head protrusion, when I want to know how much of the case is protruding from the die I remove the die with the shell holder before lowering the ram. After removing the die with the case I measure case head protrusion. Case head protrusion should be .125” if the case was returned to minimum length/full length sized. If case head protrusion is .135” (for example) the reloader has to add the additional .010” to the length of the case, for a 30/06 case that would be the equivalent of a no go-gage + .001”.

F. Guffey
 
"...so my headspace is not right..." Headspace is a rifle manufacturing tolerance ONLY.
A small base die set will do. You may not need it, but it'll do. An SB die merely resizes a few thou more than a regular FL die. It's one or the other though. All of which assumes the die is set up correctly. The bottom of the die should just be kissed by the shell holder with the ram all the way up.
Loading for a semi also requires you to pay close attention to the case length and the OAL.
"...unfired rounds stick in the gun..." Indicates excess pressure. What's the load?
"...lubricated my 308 and 30-06 cases in my Garands and M1A's..." Very good way to cause extreme pressures.
"...Gas guns open up when there is pressure in the barrel..." No, they don't. Very bad Ju-Ju for the shooter if they did. Pressure is long gone before the bolt even start to open.
 
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