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I cut out a business card to fit flush on the bolt face on my 03a3 spring per Injunbro's info. Slid a resized empty case in the chamber and put fairly light pressure to close bolt. Bolt would not close.......
I am fairly sure that I do have the correct bolt mated to the rifle......but no excessive headspace....
Being from WV..the Hillybilly Headspace Gauge goes in my tool box :grin:
Thanks Injunbro...............
 

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That Injunbro is one clever guy!
 

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He ought to know sumthin'..........he's been around the block.....probably a million times!!!!! I think he's ready for a wheel chair by now. l;nfPNFIwhappyroller Bob


But I'm still 10 years younger than Bob & my wheelchair is 4 wheel drive w/ mud tires... :)
 

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Gee....I have an AWD RAV4 with Geolander GO15 AT tires! Yeah, I've seen those 4wd wheelchairs........ with the knobby Off Road bicycle tires. nbhaof Bob
 

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My current 4wd wheelchair is a Toyota Tacoma that replaced the Jeep Rubicon - both have seats or "chairs" & "wheels" therefore qualify as wheelchairs... & I's still 10 years younger than Bob (but look 20 years younger). :)
 
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Ummmmmm.... Headspace is measured in 1,000ths of an inch.

Assuming that the case was fire formed on another gun's chamber, what was it's headspace? (variable one)

How much does humidity and prior compression impact the thickness of the cardboard in a business card? (variables two and three)

The field gauge is about $35.

Emergency medical transport and treatment cost a few thousand times more.

I bought the gauge, not the story.

Sorry, I'm kinda old school on this stuff.
 

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Ummmmmm.... Headspace is measured in 1,000ths of an inch.

Assuming that the case was fire formed on another gun's chamber, what was it's headspace? (variable one)

How much does humidity and prior compression impact the thickness of the cardboard in a business card? (variables two and three)

The field gauge is about $35.

Emergency medical transport and treatment cost a few thousand times more.

I bought the gauge, not the story.

Sorry, I'm kinda old school on this stuff.


When I built custom rifles I used the correct gauges, however in this case he wasn't building anything, just not sure which bolt fit which rifle. A hillbilly headspace gauge is a field expedient method of checking to see if it's tight enough to be safe. By the way slightly excessive headspace won't cause a rifle to explode & require "Emergency medical transport and treatment", it might cause a split case. Figure it out.
 
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I've done something similar with handguns. I carefully Mic a fired case. Then use automotive type feeler gauges instead of the business card. Length of case + feeler gauge thickness= headspace. With rifles, I guess I'd have to spring for actual gauges.
 

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By the way slightly excessive headspace won't cause a rifle to explode & require "Emergency medical transport and treatment", it might cause a split case.
Here's my reply (on the Winchester forum, where I'm "Clarence") to someone asking recently what to do about a M. '95 Winchester in .30-06 with "excessive" (whatever that means) headspace:

"This is why some loading manuals, such as Ken Water's, recommend "down-loading" .30-06 to .30-40 Krag pressure levels in '95s--the '95's rear lock-up allowed the action & cases to stretch excessively. There's no quick-fix--the barrel will have to be set back, if headspace is really unsafe. But is it? How badly do fired cases stretch? As long as you're not getting incipient head separations, & use lower pressure reloads, the gun may be safe to continue shooting."

My point: don't panic--take time to analyze the situation.
 

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So, I don't challenge field expedients, and experience based knowledge. Forum knowledge represents what has "worked" for individuals in a number of prior situations. That's all well and good.

But what do I know?

I do know that you don't have an intuitive "feel" for the kind of pressures developed by these rifle cartridges. The maximum SAAMI Pressure of a .30-06 cartridge is just over 60,000 PSI.

How do you predict where a brass case is going to split? Along the side? On the shoulder? Just above the web near the base? Primer backing out? A defect in the base or web?

As long as 60,000 PSI vents out the muzzle of the barrel behind the bullet projectile, you're going to be fine. You might have to extract half a case from the chamber, but it won't be a tragedy. When it starts venting out through the action, magazine, or stock, things get "interesting".

So... when it comes to things that I can't intuitively deal with - even after a long stream of "good luck" - I prefer to be conservative. I am at a point where I just don't take this kind of risk. Your results, of course, may vary. When I teach this stuff, I teach the conservative path.

Even Paul Mauser, himself a master gunsmith and designer` lost one of his eyes in an accident while testing a new semi-automatic rifle action.
 

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How do you predict where a brass case is going to split? Along the side? On the shoulder? Just above the web near the base? Primer backing out? A defect in the base or web?
Cases that split at the mouth pose no danger, & they often split for reasons having nothing to do with excessive pressure, like improper annealing. It's when they let go just above the web that real trouble results. (Though most bolt-actions incorporate gas venting holes in the receiver to prevent gas from hitting you in the face.)

It's easy to detect when a case is beginning to stretch by feeling on the inside of the case near the head with a little hook--when it starts to stretch, a groove will form. A hook is easily made by unrolling a paper clip & bending up one of the tips. I'm still using the one I made 50 yrs ago, though you can buy them ready made, I believe.

Another method is by comparing the head diameter of an unfired case with a fired one--expansion of more than .001 may be cause for concern, & certainly a reason to double-check for a groove inside the case.
 
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