Author Topic: Incipient case separation...  (Read 465 times)

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Offline JPH45

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Incipient case separation...
« on: November 28, 2004, 05:35:39 PM »
I forgot to speak of this part,

Lots of new reloaders get confused about the expansion ring and the ring caused by incipient head speration. Perhaps I can add to the confusion....

I have been reloading for my 30-30 most of the year now, at least 30 rounds or so a month. Today, after loading a firing the cases I have been working with all this time, I went to resize them again and found a ring around the case just abouve the expansion ring. The common knowledge is that this occurs on the inside of the case, that as the seperation nears, a bright ring will show up (hence the confusion with the expansion ring) and if one has a paper clip straightened with a small 90 degree bend that is sharpened on it, dragging it on the inside of the case will reveal the "step" where the brass is seperating. THIS IS NOT AN ABSOLUTE TRUTH. My first impression on seeing was "Where did that dirt come from"? 1 of 5 cases has a ring completely around the case. It is dirty in apperance, it undulates, is not perfectly parallel to the case head like the expansion ring) and indents from the OUTSIDE. I find NO crack or joint or seam or anything when dragging a point over the inside of the case. When I found this, as I continued resizing the group of five cases, each one shows a minor line, minor meaning you have to LOOK for it, but it is obvious on examination. Five cases of the lot (of 10) that have not been through the next firing and resizing (they are loaded ready and waiting)

The line of seperation is about 3/32" above the expansion ring as is the minor line. to all new reloaders and old alike who have not seen this, closely examine your cases as you resize them for line parallel to and just above the expansion ring. The minor lines I refer to look for all in the world to be scratches at first. On examination, it is obvious they are not. But there is little in the sizing, loading and firing of a case to make scratches along the circumference of the case just above the expansion ring. The indentation is readily evident with your fingernail (not on a minor line, at least in these cases) Had I not seen the worst example of this, I would have missed the minor lines, a glimpse is not enough to catch what you are seeing.

Another point of reference is that factory loaded brass I fired today measures 2.035", my brass measures 2.095" and has never been trimmed. That is a growth of .060" a full 1/16". I not trimming know it's bad practice guys, a trimmer is next on my list of things to get.

I used to shoot a 22-250, it had to be trimmed at least every other firing, it grew by about .004" a resizing. I've reloaded for a 30-30 in past, just never shot it enough to see this. Laziness. Familiarity breeds contempt. Not checking as I went.

For the record I have no idea how many times these cases have been reloaded. I can count at least 7, and the real figure is more likely to be something like 10 or 11. Remington brass. I bought the ammo in the early ninties.

Another point is that untill today my brass has always split on the case mouth before I've seen this. This group is brass I annealed. That was at least 5 loadings ago,  and I know I had loaded the stuff at least 4 times before annealing it. I annealed it because I was using the Lee neck sizing die on it. But I continued to have sticky cases and I couldn't prove any gain in accuracy so I quit using the neck sizing.

If I can rememebr anything else pertanent I will post it. Hope this helps others, JP
Boycott Natchez Shooters Supplies, Inc

Offline Mac11700

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Incipient case separation...
« Reply #1 on: November 28, 2004, 06:33:56 PM »
Sounds to me that you've reached the end of the  life of the cases...I'll quote frome pg. 52 of the 48th edition Lymans reloading handbook...even though you don't trim...your numbers correlate precisely...
Quote
With each trimming you may remove from 0.005" to 0.015" of material.After the 4th trimming,a total of as much as 0.060" of material will have been removed from the case.All this material has flown from the juncture of the case web and body.This leaves the case substntially weakend at the web/body juncture.Therefore never trim a case more than 4 times.When a 5th trimming is needed...discard the entire lot of cases.If case stretching is excessive,fewer firings will be appropiate.


So...I would pitch that lot of cases you've been reloading and keep an accurate count of the reloadings next time for future reference...also...if your getting your brass from factory loads...you need to count that as the first firing...

Also...as on pg 50 of the same...
Quote
Experianced reloaders can sometimes obtain an incredable number of firings from each case...however...under ideal conditions,the average reloader should consider 8 firings as a safety limit for rimless cartridgesBelted cases has a shorter life...and should be loaded nomore than 2 or 3 times...Rimmed case are often assosiated with firearms having large chambers,as a result,such cases most often provide a useful case life falling between rimmless and belted cases...


So..you probably have had a pretty good run with them...time for new...


Mac
You can cry me a river... but...build me a bridge and then get over it...

Offline riddleofsteel

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Incipient case separation...
« Reply #2 on: November 29, 2004, 10:15:49 AM »
I used to reload for the 7-30 Waters that has the 30-30 as a parent case. These cases have a long, softly curved shoulder and under the pounding in a T/C Contender the cases grew like weeds. I learned all about case trimming, head separation, and keeping proper records from that caliber.
I finally established four case trimmings as my max. After that I could feel a thin area inside the case with a bent paper clip tool. I had access to an electric hack saw and I sectioned a few older cases in a group that had been trimmed five or six times. What I saw convinced me to htrow them away after four trimmings and not look back. I had the advantage of an almost unlimited source of 30-30 empty cases from three friends that shot lever actions. One guy had a small bucket in his garage almost full he gave me.
...for him there was always the discipline of steel.

They all hold swords, being expert in war: every man hath his sword upon his thigh because of fear in the night.
Song of Solomon 3:8

Offline JPH45

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Incipient case separation...
« Reply #3 on: November 29, 2004, 11:53:54 AM »
A quite a few of those loadings were for cast bullets in reduced loads, only making about 1200-1400 fps. Again I don't know a number of loadings, but I know how many bullets I fired adn how many cases Ihave been working with. The surprising part is that I didn't get one seperate in the chamber.
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Offline safetysheriff

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Incipient case separation...
« Reply #4 on: November 29, 2004, 01:42:31 PM »
JPH'

I'm glad you got away with this without getting hurt; and I mean it sincerely.    But, it can be a dangerous game.    A dial caliper locked in at a pre-set, SAAMI-specified length, can act as a snap gauge to prevent us from trying to chamber brass that needs trimming.    It's worth the time to use the snap-gauge procedure for our own safety and for the way it makes chambering a round easier on the rifle.     We all know that pressures can build to dangerous levels with brass that isn't kept to proper spec's....and it can weaken a firearm eventually, even if it doesn't cause an immediate, catastrophic failure.

I say this not only for your benefit but for the benefit of others who may become lax in their procedures.    We're all human; but this is an activity that requires good effort on our part.    

Good hunting to you,

SS'
Yet a little while and the wicked man shall be no more.   Though you mark his place he will not be there.   Ps. 37.