case head seperation

[crankycalico]

does someone have GOOD photos of case head separation in 8x57 and .308 Winchester cases?

I have a funny shiny ring on my 8x57 that appeared after the first full length sizing, and on my new brass after the first FLS and shot.

The lyman 4th has photos of case head separation but its not in the same place as on my cases so I am curious if its case head separation or scratches from my die.

I can get a sort of shiny ring on 357 cases in the same spot.

[M-Tecs]

If you think you might be having an issue use a paper clip to reach inside the case. You can feel if you have a groove indicating future head separation.

[Char-Gar]

If you think you might be having an issue use a paper clip to reach inside the case. You can feel if you have a groove indicating future head separation.

Yep, a bent paper clip will find any problems inside the case. If you feel it "tick" on the inside where the ring is, you have a problem. However many sizing dies leave a visable ring where they come in contact with the thick portion of the case head.

[crankycalico]

I did the paper clip test. nothing.. so I guess im simply going to clean my dies out and check for anything unusual in them.

[Peregrine]

I've always done the paper clip test but I'm skeptical I could catch an incipiant seperation that way. I haven't had one either though, but maybe I really should just get one of those headspace guages to make me feel better.

[Hannibal]

I have had case head separation on .260Rem made from .308LC brass after 25+ heavy loads. The paper clip trick works. Only thing better is a bore scope, or so my experience has been.

[Hannibal]

I've always done the paper clip test but I'm skeptical I could catch an incipiant seperation that way. I haven't had one either though, but maybe I really should just get one of those headspace guages to make me feel better.

If you FLS your brass or even do a shoulder setback, then just what do you expect to learn from that headspace gauge?

[Peregrine]

I'm pretty new to reloading with just over a k rounds under my belt so I'm still just trying to find the best way of doing things.

When I set up my FLS dies I just screw them in until they touch the shell holder, and then another 1/4th turn or so.

Clearly this sets my shoulder back enough since I don't feel much resistance clambering. But maybe I'm setting it too far back? Maybe one of my mausers (I developed my loads to work in several different rifles at once) has excessive headspace and I just haven't fired the same case through that rifle enough times to notice yet, but I'm overworking the brass to the detriment of everything.

My bet is no, everything is fine. But without measuring it, that's just a guess.

[M-Tecs]

For best case life setting the shoulder back .002" is preferred. These tools work well and Amazon or E-bay has way better prices.

https://www.hornady.com/reloading/pr...il-base-kit#!/

http://rcbs.com/Products/Case-Prepar...ision-Mic.aspx

details here:

http://www.massreloading.com/bottlen..._resizing.html

[Hannibal]

Peregrine -
What you are currently doing is resizing your cases based upon the dimensions of your FLS die and shell holder. This has nothing to do with your chamber length. This may or may not be causing you trouble. It all depends upon your chamber and your dies.

PM me if you do not understand what I am speaking of and I'll try and help you.

[country gent]

If you bring the wire to a sharp point on the paper clip before bending it you can feel a very fine groove ( start of the separation). As said a bore scope is good also here you can see the ring forming and judge how deep it is. I have used my hawkeye for this several times.

Full length sizing and pushing the shoulder back farther than necessary accelerates the head separation and groove formed, Carefully setting the sizing die to the firearm in question, Ie bump sizing. Only bump the shoulder back .002-.003 Instead of the .008-.010 dies do when set to touch the shell holder greatly slows the separations and allows for more loadings. Some firearms are more prone to this due to function. M14/ M1As, Garands, ARs and some other semi autos are notorious for pulling case heads out of square and speeding separations with the violent extraction.

[Bama]

I normally shoot a 100 rounds per week so brass sees a lot of use. Initially I was getting frequent partial head separation starting after about 10 reloads. After one very near total separation I got an RCBS precision mic. I resetsizing die so that I only bumped cases back to within 1 thousand of as fired case dimension so case working was reduced to near minimum. Case life jumped to 15 reloads and then it was neck splitting. I have not run any side by side comparisons but it seems that the rounds are more accurate very close to neck fired only. FWIW.

[crankycalico]

When I made my patented bent paper clip case head testing tool, (10.00$ plus 4$ shipping and handling)(buy 1 get on free till January 1st) I cut the leg half way through the bend with wire cutters, very sharp point.

Im thinking of just switching to neck sizing my mauser,

[country gent]

A quick shoulder gage can be made with a 3/4 or 1" nut. Lay out center of a flat and drill thru (For your 8 mm a .330 or so drill thru then counter bore one side to .390 - .400 .100 deep. break the sharp edges and remove any burrs. set this counterbore down on a fired case and measure with your calipers. Write the number down. better is to measure 10 fired cases and average. Now adjust your sizing die to this dimension -.001 - -.002. you are now sizing to min amount needed and this will extend case life and also may improve accuracy.

This simple gage will measure from a datum on the shoulder to the case head, not an actual measurement but a comparative measurement you can use to set dies. its simple with a drill press to make. Another way to make these is to roll a paper tube 1" id 1 1/2" long. give a dummy round 2-3 coats of wax and let dry. wrap with a cartridge with a 1/2" wide strip of paper to a snug fit in the paper tube. coat inside of tube and cartridge with wax again. Fill level full with epoxy and let cure. remove cartridge and tube. Dill thru at neck dia + .003-.005 clean up ends with a file square and tru. This will work the same as the above nut. For other cartridges, measure loaded neck dia and add .005 for clearance. For checking sized and fired cases you don't need the thru hole just the neck dia +.200. but with the thru hole you can check loaded rounds to trouble shoot things.

[EDG]

Just do a google search for case head separation and click on images. There are a lot of photos. Some of the photos are associated with an article on the subject. Click on an interesting photo an follow it to the article.
Most folks can avoid case head separations by setting the shoulder back not more than .002 inch. I try to form new cases to exactly .000 set back. I try to get a perfect match for rounds that are fire formed at the range. For other repeaters used for hunting .002 setback may be best.

[Skipper]

I did the paper clip test. nothing.. so I guess im simply going to clean my dies out and check for anything unusual in them.

Cut one of the cases in half lengthwise and look at it.

[popper]

I had a case head separation in my XDm 40. No damage but it sure shuts down a range session. It was a bad batch of FC cases, known problem but range brass is free? You still go looking at all the body parts to make sure they are OK. Set your die correctly and inspect the cases. Yes, the outside 'ring' is usually the bottom of the sizing die action.

[Rich/WIS]

Where is the bright spot, near the head just above the web or farther up the body. Remember that the case new or resized is smaller in diameter than the chamber and when fired will expand until it hits the chamber walls. Brass has spring back and will shrink slightly which is good as it releases the brass for easy extraction. The bright ring is caused when the sizing die reforms the brass to cartridge dimensions and is normal. Unless you have overly large chamber or a sizing die that is minimum dimension you are good to go. You can back off the sizing die if you want, start with a fired case and the sizing die backed out about a half turn, Remove the decapping rod and then size. You will be able to see where sizing on the neck stopped. Adjust the die down until the neck is fully sized and then a tenth of turn, maybe even a little less. This should set the shoulder back enough to assure easy chambering and minimize case stretching. You don't say what rifles these are used in, assume 8mm is a Mauser bolt which you can neck size only, same for a 308 boltgun. FL is only needed for an action that does not have the camming power of a bolt gun.

[BK7saum]

Also, if you carry your ammo/cases in plastic Berrys or Midway cartridge boxes, be mindful of the ring left by the cartridge box. The vibration of the empty cases in the box (case head up) will leave a shiny ring on the side of the case and look like an incipient case head separation ring.

[EDG]

This is correct.
A case head separation is really a frosted area of stretched metal.
Shiny rings are something else.

Also, if you carry your ammo/cases in plastic Berrys or Midway cartridge boxes, be mindful of the ring left by the cartridge box. The vibration of the empty cases in the box (case head up) will leave a shiny ring on the side of the case and look like an incipient case head separation ring.