No wonder we are losing the battle....

[Patrick Chadwick]

OK, Son, I'll give you a clue:

The case was stretched about 1.3 mm compared with the reference.

Information

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[Patrick Chadwick]

Now round it off and think about it

[jmoore]

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Now round it off and think about it<img src="https://www.milsurps.com/images/smilies/wink.gif" border="0" alt="" title="Wink" smilieid="4" class="inlineimg" /></p>

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<p><img src="images/smilies/wave.gif" border="0" alt="" title="Wave" smilieid="25" class="inlineimg" />

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0.050"?, 0.051" That's about 20tpi...Phooey!

[Patrick Chadwick]

Well done jmoore - you are on the right lines,!

The only ex-service rifle I have had in my hands that was so seriously out on headspace that you could consider it to be hazardous, was just before Christmas. It was, of course, an...

... example of a Springfield 1903A3

I never had the chance to closely examine the rifle, which has now been disposed of, so I shall never know the truth, but I was able to measure the fired cases. Either Bubba charged in with the reamer without looking where he was going, or (my theory) he completely FUBARed cutting the extractor groove or fitting the barrel, and ended up with it 1/2 turn out of register - hence the 1/20" as half of a 10 tpi turn.

From memory, the Bubba clues were: the number indicated a 1903A1 Springfield system, but fitted ("fudged"?) with a 2-groove barrel - surely WWII - and a totally unnumbered/unmarked "C" stock with no arsenal rebuild stamp. Add to this the fact that the backsight assembly was loose on the receiver, and it all looked like a D-I-Y A3. If the owner had simply applied my threaded rod method (see the Argentine Rolling Block thread) before purchase, he could have saved the ammo, and his money.

It was another case of: at that price it was to good to be true, and so indeed it was.

The really surprising result was: 20 cases had been stretched by 1/20 inch - and NONE of them had separated, although 18 of 20 showed the ominous bright line of incipient separation. 2 cases did not even show the bright line. On reloading (neck sizing only), one case survived intact and the second separated. End of experiment.

Now: a general question for all the excessive headspace worriers.
If 20/20 cases did NOT separate when stretched 50 thou, why all the neurotic fuss about rifles that have a few thou excess headspace? Who fires gauges anyway?

Someone will surely shoot me down for writing this, but it seems to me that the principal cause of head separation in cartridge cases is full-length resizing of cases fired in military chambers that were never built to SAAMI or CIP standards. I have not yet had a case separation in any of my service rifles, which get an exclusive diet of new or neck-sized cases. The rifles themselves are not bothered by head clearances up to levels that the gauge neurotics would consider downright dangerous.

Don't bin the rifles - bin the cases!

BTW, the rifle shot very accurately in practice! An old development engineer's quip goes:
Theory is when it should work, but doesn't.
Practice is when it works, but nobody knows how.

Patrick

[Son]

Well, I was excused from that quiz. You could record my knowledge of Springfields in size 14 bold type on the edge of a postage stamp.

Great info, Patrick. Good to see some headspace worries put to bed on rimless ammo/ chambers too.
Got any more?

I like the quote...
"Theory is when it should work, but doesn't.
Practice is when it works, but nobody knows how."


The first thing to remember with milsurp rifles when talking about headspace, chamber clearances or head gap, is the grunts didn't pick up and reload cases. If it didn't destroy a case so it wouldn't extract, it was fine to use until an armourer told you it wasn't.

Just a reminder, this thread is open to input on any calibre or make of milsurps- not only the L.E. The topic (loosely) is the bad info that's out there for the unsuspecting browser... stuff you've seen done that might ring the alarm bells

[Patrick Chadwick]

Got any more? I like the quote... "Theory is when it should work, but doesn't. Practice is when it works, but nobody knows how."

"If cursing and hitting it with a hammer doesn't work, you can always - as a last resort - try reading the instructions."

[jmoore]

I never did finish my "maximum safe radial expansion" series of experiments on that old thread, but the next set of rounds are loaded, including some of the previously abused cases. (Nor the 300WM experiment!-but it could be brought back to life yet- horrors!) Just a warning!!!