All this headspace information

[bigdaddy]

All this information about headspace issues and broken cases concerned me to the point where I was fearful to go to the range with my refinished (but unheadspaced)
No4 Mk1. Well I went today and shot 15 rounds of Winchester ball and to my great relief the gun didn't explode and I came home with my face and fingers.
I also was able to shoot my fathers IBM M1 Carbine which has neither been headspaced nor shot since 1945.
Both rifles performed flawslessly. The carbine patterned 5 inches high at 50 yards probably a 3-4 inch group. The Enfield patterned 6 inches high at 100 yards. I ain't talking about the grouping, I am, however, looking for a new aperture sight.

Information

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[Peter Laidler]

Hey big daddy, you've got it right. DON'T worry about it. And another thing. There's only two gauges you need to headspace a Lee Enfield and that's a .064" GO and a .074" NO-GO. Borrow someone elses, check your rifle and give them back. And then use it on and off for the next five years or so and if you remember it in 2014, you could test it again!

Just ask yourself how often the Russians check the CHS of their AK's. I'll tell you what....., they don't - because there's no formal figures out there by which you can make the gauges. There's lots of guesses...........

[ireload2]

One Canadian military document for the #4 rifle described the proper headspace for a Lee-Enfield to be .074. If the .074 gauge was accepted the next shortest bolt head that was supposed to be used that would not accept the .074 gauge.

Some of the discussion I have seen on Lee-Enfield forums have recommended setting up Lee-Enfields shorter than .074.

I have purchased a lot of once fired brass over the last 35 years to be be reloaded. Of that brass .303 British is the only brass that I have ran into that has had incipient or partial head separations from being fired with factory ammo. I think it is worthwhile to pay attention to head space on these rifles. I have bought a rifle that did have excess headspace that was not a Lee-Enfield. It was/is a 1898/09 Argentine Mauser. From close examination it appears to have been arsenal overhauled and the worker did an exceptionally poor job. The rifle has about .030 head space over the length of a no-go gauge. The barrel has been replaced, reserialized and refinished and has seen a lot of handling
since the overhaul but little shooting so the bore is still in very nice condition.

[ireload2]

Just ask yourself how often the Russians check the CHS of their AK's. I'll tell you what....., they don't - because there's no formal figures out there by which you can make the gauges. There's lots of guesses...........

I don't know about the Russians but SAAMI has the 7.62X39 Standardized and the dimensions for both the cartridges and the chambers are on the internet.

[Bindi2]

Ask your self this is SAAMI the original designer or manufacturer or just a johnny come lately making alot of noise about something they know little about which is taken as gospel by others who even know less.

[ireload2]

Ask your self this is SAAMI the original designer or manufacturer or just a johnny come lately making alot of noise about something they know little about which is taken as gospel by others who even know less.

What is your point? You seem to be the newcomer here?

When the Ruskies were mostly peasants and ruled by a Czar they had to go outside the country to buy rifles.







BTW check out this 1895

[S-A-M3]

bigdaddy, ignore what ireload2 says just another techogeek trying to promote himself

[RJW NZ]

I asked this question a few weeks ago and got this great reply from Alan de Enfield about 303 headspace, it gave me a good clear mental picture of it all.

Now I'm asking the same question about 7.62 and my 1066 ishapore. This rifle seems very tight on the headspace, with the bolt requiring some force to close the handle. (Don't worry, it hasn't been fired like that. All else seems OK, so I suspect too tight headspace. ). With a cartridge chambered, what should the gap be between the cartridge and the bolt face?
And B) who stocks a no go gauge for 7.62? I've been looking but apparently in the wrong places.
And C)...is tighter better, as in zero gap? What would the penalty be?
thanks in advance...R


From the previous post;

Quote:
Originally Posted by RJW NZ View Post
Hi all, I have a question, if there's a round chambered what is the ideal or allowable gap between the cartridge and the bolt head face? Just looking for a a simple way to explain all this stuff.
Quoted headspace of 0.064" - 0.074" is without the cartridge, 303 cartridge rim thicknesses vary but are normally around the 0.059" - 0.060" so the 'gap' (as in your question) can be 0.003" - 0.014"
Tighter is better (as they say)

[Peter Laidler]

As for 7.62mm CHS gauges, in Britain, we had MANY variables. BUT, so far as this forum is concerned, we only had ONE set for bolt action rifles..., from the L8 series, right up to the L81 and that is 1.628 GO and 1.635 NO-GO. The other sizes relate to machine guns where heat, expansion and locking/unlocking methods all come into play.

On the basis that these figures are correct for British made bolt action 7.62mm rifles, then I see no reason why these figures should not be absolutely correct for Indian made Enfield Rifles.

The problem is anyone can make a 7.62mm gauge and call it, well, whatever they like! Ours are all calibrated from a diameter around the neck to the base. I can check the calibration of your SAAMI gauges against ours

[Alan de Enfield]

Anyone for 7.62mm CHS?
Posted By: Peter Laidler
Date: Tues 6 May 2008 11:36 am
Now for the biggie, the 7.62’s. The basic principle of headspacing hasn’t changed here but the practicalities have. Whereas before, on our rimmed .303” rifles we measured the GO NO-GO distance between the front face of the bolt and the rear face of the barrel, it’s all changed for the rimless 7.62mm NATO caliber rifles. Now we have to measure from the front face of the bolt to the cartridge seating at the neck. Well, that’s all pretty clear then ….., except that the neck is tapered so where EXACTLY on that neck do you take your GO, 1.628” and NO-GO 1.635 measurement from? Even if I told you it’d make no difference whatsoever because without the specialist measuring and more importantly, the calibration equipment, you’d still be none the wiser. The trouble with this is that you’ve got to take the word of the manufacturer of the gauge. And exactly where does HE take HIS measurement from but more importantly, WHO does he get them from. geting difficult isn't it?
Let me give you an example. My GO gauge gives you a close/GO reading of 1.628 but Bloggs & Co gauge may give you a GO reading of 1.575” for the same 7.62mm caliber. How can there be a difference of .053” between the two when they are identical? Well, it’s simple really. Our STANAG gauges are measured from one diameter around the neck while Bloggs & Co are taken from a different but larger diameter .053” further to the rear! That is really all I want to say about that.
The next obvious question for all you enthusiasts is where can I get a set of these gauges and the true answer is that I don’t know! But here’s what I propose. If you HAVE a set of spurious/said to be/reported to be/hope they are 7.62mm headspace gauges, I will calibrate them for you and tell you EXACTLY what it is you have. The fact remains that there are MANY gauges for all manner of 7.62mm rifles and machine guns ranging from the little bolt action L8’s right through to the L- whatever it is ferocious mini gun. And there are equally MANY for different lines of repair and functions, ranging from 1.622” to 1.648”.
Once I return them, calibrated, at least YOU know that if the ‘unknown’ gauge you sent to me to be calibrated comes back as a STANAG calibrated 1.6325 gauge (GO for the L1A1 rifle incidental.....) then it will suffice as a NO GO gauge with your 7.62mm Enfield provided that you slide a sliver of .003” steel shim across the bolt face first, on the basis that 1.632 plus .003 equals 1.635.
On the other hand, if you’re clever, you COULD just have the rear face ground down by .0045” to end up with a 1.628” GO gauge.
That just about covers the 7.62mm versions. The question of calibrating your gauges is one that needs to be looked into by ‘some friends’ on both sides of the pond. I can see already that this is about to open up a whole new can of worms...... But just hang on in there....................