556 case buldge

[oley55]

after de-priming, swaging, and pin media cleaning my cases, I found 3 cases out of 150 once fired American Eagle 223 brass that displayed case bulge. Enough so that they would not fit into my LE Wilson case gage Using a caliper; just below the bulge .372-.373" and on the bulge .380". So that's a .007" to .008" bulge.

unless I somehow picked up a few pieces of someone else's FC brass, all came from my own bargain basement DPMS Oracle 556. I have measured 18 fired cases for headspace and all were 1.770-1.771". Note: because of the bulges I was unable to measure them for case headspace length.

I guess my questions are:
1. is it possible these cases had an overly heavy factory charge?
2. could this be a weapon issue?
3. Is 1.770-1.771" relatively normal for a low end AR
4 confirm I should subtract .004" from 1.770" for setting my full length resizing die to 1.766".

[precision_shooter]

Any bump firing/rapid firing of the weapon? Possible that a few may have fired without completely going into battery?

[jepp2]

Enough so that they would not fit into my LE Wilson case gage

I don't think this is the case, but any burrs on the rim will cause cases not to enter the Wilson case gage and get a true reading. I always put them in head first to check for burrs before checking the shoulder.

What resizing die are you using? How are you adjusting it? Without pictures, it is somewhat guesswork on what your measurements are. I have never seen a bulge on a bottleneck rifle case after sizing. I have seen bulges on pistol cases especially 40 S&W and occasionally 9mm.

Have you tried chambering them in your rifle? Case gages are useful tools, but nothing is as useful as the chamber on the weapon.

[steve4102]

Pictures would be a big help.

[F. Guffey]

": because of the bulges I was unable to measure them for case headspace length"

That puts you in 'the in-crowd', no one can measure case head space, because? The case does not have 'head space', the case has a length as in the length of the case from the shoulder/datum to the head of the case.

You will be sold another tool, you are setting yourself up for a small base die and a comparator, also called a head space gage, nice tool, but not necessary.

When it comes to sorting cases I do not have the periodical son complex, I have no problem loosing the suspect and bad cases, if is swollen and has a bulge added to the problem :I do not know where the case came from and I do not know what rifle fired it, the case is rejected.

I sort bottle neck cases in groups of 20, the 20 cases stay together for their little short life.

F. Guffey

[F. Guffey]

"Case gages are useful tools, but nothing is as useful as the chamber on the weapon"

Jeep2, there is no shortage of barrels around here, purchase a gage? Cutting the chamber off of a barrel with a band saw and finishing in a lathe is a great way to make gages, I have no problem finding worn out barrels for $5.00.

You can imagine, walk into a sun shop, look down the barrel and point out the barrel has been rendered scrap, something like stealing wheel barrows,

F, Guffey

[oley55]

jeppp2

am aware of the issue of mouth burs preventing the round from fully seating into the case gage. the Wilson gage has enough play to allow you to insert a case head first to about one third length. the three with bulges stopped well short of what all the other cases. so it is definitely the bulges which are preventing them from dropping into the gage.

dies are Lee dies but I have not used them yet. I wanted to measure a good number of cases fired in my weapon so as to determine what the headspace is for my rifle with the hope of eliminating too much stretch at each firing and hopefully allowi me to get four cycles out of each case before scrapping.

I am pretty sure the die would have removed the bulge.

[oley55]

Fguffy

as per: That puts you in 'the in-crowd', no one can measure case head space, because? The case does not have 'head space', the case has a length as in the length of the case from the shoulder/datum to the head of the case.

isn't measuring the difference of a fired case in a case gage in effect giving me a reasonable approximation of what the headspace is for that particular weapon. i.e. the Wilson case gage is 1.760", the fired case measures 1.770" in the gage, or .010 over spec. doesn't this give me the information I need to adjust for shoulder bump of .004 for an AR

[oley55]

haven't figured out how to post pics, besides I already pinched the mouth shut on these cases so as not to try and use them. but then again the pinched mouth is not anywhere near the bulge so a pic would still show an undisturbed bulge.

[oley55]

no rapid fire at all. they would kick me off the range if I tried

[F. Guffey]

"the Wilson case gage is 1.760", the fired case measures 1.770" in the gage, or .010 over spec"

No, .010" protruding from the case length gage means the case is .015" longer that than a minimum length case, aslo meaning the case is .010" longer than a go gage length chamberr 'IF!' we are talking about a 30/06 chamber.

I am very busy at this moment, forgive if I seem out of character,

F. Guffey

[oley55]

F Guffey,

we are talking about 223/556 in an AR. Here are links to a video from LE Wilson available on you tube and their site.

http://www.youtube.com/watch?v=RuJYpm-qplQ
http://www.lewilson.com/productvideos.html

if I am understanding you correctly (case gages are really only useful for "go, no go" case length). Then this information from LE Wilson would seem to be useless in regards to sizing case lengths to/for my weapon's demonstrated shoulder case length (headspace?)

not trying to argue or otherwise, I just trying to get my head around this.

thanks in advance

[243winxb]

A test would be to see if the bulged brass would fit back into your rifles chamber, if in fact, brass was from your rifle. But to late, you destroyed the evidence. http://www.saami.org/PubResources/CC...0Remington.pdf

[dmazur]

See this, to start -

.223 Remington cartridge and chamber dimensions

1.760 - 0.020" is the spec for case length. This is absolutely something different than the measurement to the shoulder, sometimes called "cartridge headspace" or "head to datum".

The dimension you are trying to control needs to fit a chamber headspace of 1.4636 - 1.4736". The cartridge drawing shows 1.4596 - 1.4666" as acceptable for the cartridge dimension, head to datum.

The instructions for the Wilson gauge suggest using a straightedge on the base of the gauge to estimate how far the case head is below the upper step of the gauge. However, you can use the tail end of calipers to make this more than an estimate.

For a semiauto, I believe it is considered good practice to set up your resizing die for 0.004" or so less than the fired dimension.

Also, you should be aware that, if you stand the gauge on a surface to make measuring the head depth in the gauge easier, the case mouth must not protrude from the "trim length" end of the gauge or it will mess up head measurements. (If it does, trim it to the bottom step.)

Cartridge headspace (more correctly termed "head clearance") is controlled by setting up your resizing die. Case overall length (aka COL, or COAL) is controlled by trimming.

As far as I know, you can't set up your resizing die with a COL measurement..

ETA -

OK, I watched the LE Wilson video for the standard .223 gauge. The video shows using a caliper to measure from one end of the gauge to the head, using the standard outside jaws. (Works OK, as long as the case mouth doesn't interfere.)

After showing resizing 0.013" less than fired length, the demonstrator goes on to say that only 0.004" for an AR, or 0.001 to 0.002" for a bolt gun, are necessary.

If you are measuring 1.770" (using the technique shown in the video), you should be adjusting your resizing die for 1.766", as you originally said.

(The 1.770" dimension doesn't match the cartridge head to datum distance in the drawings, but it does match cartridge length. Sorry for the misunderstanding...)

[oley55]

dmazur,

thank you, I am pretty sure we are on the same page. and yes I have found after sizing I get some long cases hanging out beyond max case length and have been careful in my measurements.

I think I may have been trying to put the cart before the horse in regards to fired case dimensions before even starting any workup loads. My plan now is to load my starting loads using 1.760". Once I have a load I am reasonably happy with I will load some to 1.766".

then I think I want to validate for myself if I really get more cycles out of brass sized to 1.766 versus 1.760".

I am not expecting tack driving accuracy from this DPMS Oracle AR15 no matter what I do in regards to round preparation. For now, I am after safe, reasonably accurate and economical rounds for general plinking.

[243winxb]

Bulge is outward in diameter. Stretch is head to datum or trim length.

[dmazur]

I am far from an expert in this area, having experience only with an M1 Garand as far as gas guns go...

My understanding is that proper chambering is a must, and overrides concerns about brass life. That is the primary reason behind recommendations for 0.004" of shoulder resizing vs. 0.001 - 0.002" for bolt guns.

But if you get proper chambering with 0.004", I don't believe there is any advantage to deliberate over-resizing. This is termed "induced excess headspace", because, as far as the case is concerned, it stretches to hit the bolt every time it is fired. The result is the same as if you had excess chamber headspace.

Unless your chamber headspace falls within the steps on the Wilson gauge, there is nothing "magic" about that bottom step, in other words.

[oley55]

"Unless your chamber headspace falls within the steps on the Wilson gauge, there is nothing "magic" about that bottom step, in other words."

I think I musta read that statement six times before I was sure I didn't get it.

[Travelin' Man]

Oley55,

Are you concerned about headspace simply because of extending the life of your cases or are you attempting to improve accuracy?

If your answer is yes for extending the life of your cases then I would say that you would be far better off full length resizing with small base dies and annealing the brass every time you process them rather than worry about a few thousandths of an inch in stretch.

I have a friend who reloads for commercial accounts and while I have had an issue with a batch he loaded for me two years ago being about .007" over the max guage length, my DPMS barrel must have a tighter chamber than most because the rounds fire fine in my Ruger Ranch Rifle and my buddies Olympic arms AR but not in my DPMS Sportical with 16" bull barrel. He was getting 5 to 6 cycles of reloading cases that were not annealed and since he acquired a Giraud Tool annealing machine he has had one customer bring in brass to be reloaded over 10 times with no neck splits or deformations.

You can easily anneal the brass yourself when doing small quantities by using a cordless drill with a rod and socket and a torch with propane gas. Here is a link to a youtube video demonstrating doing it like that:

https://www.youtube.com/watch?v=Mi3OoeYUPec

[dmazur]

Originally Posted by Oley55

My plan now is to load my starting loads using 1.760". Once I have a load I am reasonably happy with I will load some to 1.766".

The Wilson type "headspace gauge" is often maligned because it assumes your chamber is within SAAMI specifications. The top step should be the maximum cartridge "head to shoulder datum" length and the bottom step should be the minimum.

Anything longer than the top step should not fit a SAAMI spec chamber, and anything shorter than the bottom step will create the condition I described above, "induced excess headspace", even if the chamber is in spec.

If you have a fired case which is actually touching the shoulder datum inside the gauge, and it measures 1.770" (using the gauge as shown in the video), you have a rifle with actual excess headspace.

This is potentially dangerous for the reloader. While a new case will probably withstand 0.010" of stretch on one firing, that case may not handle successive firings. Case head separations will occur, especially if the case is over-resized each time it is reloaded.

With a chamber in spec and resizing to SAAMI minimum, the case is only being resized 0.006" or so (depending on the cartridge.)

I have no idea how many times you can reload a case which has been stretched 0.010" on its first firing. My suggestion is to minimize case stretch by resizing 0.004" from your fired dimension, as recommended for gas guns, and see if you have proper chambering without any resistance, rather than use either step on the gauge as some kind of goal.

Many people successfully reload for bolt-action rifles without using a gauge. Actually, they use the rifle's chamber as a gauge, and adjust their resizing die down in very small increments until they just get a fit with a resized case.

But as gas guns don't have the camming power that bolt-actions do, and because there is a small but real risk of slam-fires on cases which don't chamber easily, more resizing is necessary for gas guns. 0.004" shorter than the fired dimension is suggested as a workable compromise between chambering success and brass life.

0.010" of deliberate resizing is excessive, IMO...

[James K]

Did you measure a sample of the cases at that point or only the ones that appear to be bulged? Cartridge cases often show a considerable variation in dimensions, which is not a concern as long as they don't exceed the maximum and minimum specifications. So, a "bulged" case may simply have started out smaller than one that doesn't show a bulge, because there is more space between it and the chamber wall for it to expand. Case dimensions from a given lot should be fairly even, but in mixed batches of brass, dimensions can be all over the lot and still be within specs.

FWIW, it is because cases, even new unfired ones, do vary in dimensions, that factory cases should not be used as gauges; each one is essentially an unknown quantity. Not sure of that? Here are some examples, from .308 Winchester specs:

The case diameter at a point behind the shoulder, can vary from .4473" to .4553". The chamber diameter at the same point can vary from .4564" to .4584". These are SAAMI factory specs; reloaded cartridges may vary more depending on the reloading dies, which generally are made to size the case smaller than factory dimensions.

So if a large case (.4553") is fired in a small chamber (.4564") there will be little bulge, only .0011". But if a small case (.4473") is fired in a large chamber (.4584") there can be a bulge of .0111", which could be noticeable. Of course, the elasticity of brass means that even a fairly large bulge will "spring back"; I have used theoretical measurements here.

Jim