Just one further comment. If you will read my post above detailing the military gages you will not see anywhere on them the terms go,no go,or field. I am trying to remember ever reading the terms in any manuals while I was in the military. I have always heard them refered to by those terms,but they are definitely not marked that way,at least on the ones I have and they are stock military issue. It would be interesting to learn where the terms came from and when they originated.

I once saw a cased set (compartmented cardboard box, grin) of military issue 30-06 headspace guages that were graduated in increments of 0.001". They included the minimum Go, the Maximum No-Go and the Field, as well as gauges in all the intervening measurements. Sorry, no war gauge included. These were gauge sets offered 'for sale' by a surplus dealer and were represented as being the complete set as issued to a US forces armorer.

FWIW, no flames intended.
Regards, Joe

Not a problem, only I'd rather have a large memory and short library, that way I wouldn't have to look far.

JD, my dad has such a set, passed down to him by his Uncle, My Great Uncle and he was a Gunsmith as well. My dad doesn't know quite how to use them, but knows of their importance, as in the hands of some one who does know how to use- or read them correctly. He knows what go, and no-go gauges are, the others are confusing to him at his age.

quote:

Originally posted by zimbabwe:
Just one further comment. If you will read my post above detailing the military gages you will not see anywhere on them the terms go,no go,or field. I am trying to remember ever reading the terms in any manuals while I was in the military. I have always heard them refered to by those terms,but they are definitely not marked that way,at least on the ones I have and they are stock military issue. It would be interesting to learn where the terms came from and when they originated.

I have never (yet) tried to research that question, but I know for a fact they were in common use well before 1930. My guess is that they go back almost to the time of the Krag. They certainly were in use shortly after the Springfield '03 entered service, as there were bulletins issued directing Army small unit armorers as to when to pull an already issued and in use rifle from active service and send it up to higher echelons for servicing (repair).

I suspect that is where the term "field" comes from...as rifles already in soldiers' hands which gauged "no go" (closed on the x.x46 gauge), were specifically NOT to be pulled from a unit's active service. Rifles which closed on the x.x50 gauge were to be pulled from service in the field and sent to designated specialized repair facilities.

When I was an armorer, the headspace gauge that was used to remove weapons from the field for being considered unsafe for combat use was called a "Field Reject Gauge" and it was .008 over go.

quote:

Originally posted by Westpac:
When I was an armorer, the headspace gauge that was used to remove weapons from the field for being considered unsafe for combat use was called a "Field Reject Gauge" and it was .008 over go.

Yes, standards were tighter by then. The bulletins I referred to above were issued decades before that. And it is always possible that "Field" is just a verbal shorthand name for "Field Reject Gauge" but reflecting the earlier .010" standard for rejection.

I was never actually an Armorer in the Army. I actually didn't take basic training. When the Colonel who was battalion commander found out I had my own M1 and 1911 target grade weapons he pulled me out of the regular routine, made me an acting Corporal and put me in charge of small arms. The WO in charge of Supply always reffered to me as his 'Artificer' which hasn't been a military rate for probably 100 years. I was told to inspect the rifles after every range session and if any closed on the field gage (1.1950)to tag them for repair. If they closed on the no-go gage (1.946) they were ok for reissue. Therefore the tolerance seems to be a very narrow .004 to what I assume was a dagerous condition. So it doesn't take much slack so to speak to be a problem. Does this variance more or less stay the same no matter what the caliber or case type, such as rimlees,versus,rimmed or belted? Just came to mind with this discussion, I have just always checked them and never really paid any attention to what actual measurements were.

You and I both know how CYA works. That is doubly true in an enterprise which historically has everyone and their brother's dog looking at it and criticizing it...like the U.S. military.

From the data and reports I have read, I suspect that is part of the reason for pulling rifles from the field which gauge x.x50. (Or, as WestPac posted, at an even tighter standard in his days as an armorer... x.x48", which is only .002" above the no-go gauge.)

A large organization like the Army can't spend its whole resources examining individual weapons to see if they are actually safe to use or not, with the ammo they are likely to draw in the distribution "lottery" which is field supply. So, they set a standard which in their world is not a MAYBE, but is a YES or NO. Either the rifle passes the gauge inspection and stays in service, or it fails the inspection and is taken out of service. You know the drill..."You there, Jump!"... "Yes SIR! How high, Sir?"

But as I posted earler, E.C. Crossman who had more to do with the Springfield and .30-06 ammunition than all of us put together, did numerous tests for the Army which showed that headspace greatly in excess of the x.x50 "field" gauge standard was quite safe to fire. Not in every single instance, but in so many instances that the unsafe ones IN HIS OPINION faded into insignificance.

He is the same fellow, incidentally, involved in such things as running the maximum range testing of various '06 bullet designs on the beaches in Florida...

So, yes, for work being done for other folks, it is very wise to adhere to publicly approved and standardized dimensions.

But it doesn't mean that Thor WILL strike you with a lightning bolt if you use a rifle with even greatly excess headspace. What actually will happen depends on a whole lot of other things too.


For your own use, it is also a good rule to follow UNLESS you know what you are doing, are willing to assume 100% responsibility for any and all unintended consequences, and have a bona fide reason for doing it. Take a look at Rocky Gibbs' experiments & wildcats as an example.

quote:

Originally posted by Alberta Canuck:
(Or, as WestPac posted, at an even tighter standard in his days as an armorer... x.x48", which is only .002" above the no-go gauge.)

Actually the 7.62 Field Gauge is .004 over no-go.

quote:

Originally posted by Westpac:

quote:

Originally posted by Alberta Canuck:
(Or, as WestPac posted, at an even tighter standard in his days as an armorer... x.x48", which is only .002" above the no-go gauge.)

Actually the 7.62 Field Gauge is .004 over no-go.

Sorry WestPac, I thought your earlier post referred to the .30-06 cartridge. I must have missed its mentioning the 7.62x51 round. So I just used the simple math of x.x40 + .008" and compared it to the x.x46" '06 no-go gauge to get that .002" in my last post.

When I was in the service the M14 was just being introduced. I never actually saw one. Actually my TOE weapon was the Thompson SMG replaced by the M4 'Grease Gun' all others were issued M1's. I qualified with all three. When I was working as an armorer they were all M1's.

Me too Zim -

I was about a year+ into my third hitch as a wanna-be gung-ho RA lifer when I was air-evac'd home and "invalided" out. In my work I was allowed to carry whatever I chose, and I too carried a grease gun most of the time. Never had to qualify with it, but qualified Expert with both the M-1 and the 1911. The M-14 was still a dream never seen in our theatre.

Of course we were still wearing brown boots, the winter Class As were still OD/Brownish wool, and the jacket was the Ike jacket cut.

Those were the good old days; was still in my 20's and gonna live forever.