M1917 Headspace Question

[swede49]

My Eddystone 9-18 does not pass the field gage test using a Forster gage, which is SAAMI spec. Is that the final authority, or is there a military spec for these old rifles? I have fired it, and was pleased with results.

[kcw]

I would assume that the GI gauges for both the 03 Springfield and the 1917 are the same? GI gauges for the Springfield are 1.940", 1.946" & 1.950". "The 1.950" is used in the field, and the 1.940 & 1.946 are used for testing in the arsenal or depot." (As per TM9-1270)
Info I've seen says that the 17' bolt needs to be stripped and that a very light finger must be used when closing the bolt on the gauge.

[Dan Shapiro]

"Info I've seen says that the 17' bolt needs to be stripped and that a very light finger must be used when closing the bolt on the gauge. "

Don't forget, it's a Brit design and cocks on closing, so use a stripped bolt in order to get the proper feel.

[swede49]

Forster SAAMI field gage reads 2.0577, so apparently the '03 and '17 gages are not interchangeable. You're correct about the stripped bolt==force of the striker spring on closing makes it tough to feel anything, especially subtle pressure. Without stripping the bolt on a BSA #4 Mk1, I would never have felt it "pass" when testing an Okie disc field gage, it was that close. I was stunned that it passed--first and only one of my Enfields that ever did.

I guess my overall question still is: with military rifles like the M1917/1903/SwedeM96/Kar98 and others with their greater tolerances, and mauser type actions with multiple locking lugs and gas holes in the bolt and receiver, how critical is one or two thousandths of an inch? And then of course there is the question of rimmed cartridges...oy vey!

:1948::1948::1948:

[fguffey]

“1.940", 1.946" & 1.950". "The 1.950"
“
http://www.saami.org/PubResources/CC_Drawings/Rifle/30-06%20Springfield.pdf

1.940", 1.946" & 1.950" are measurements from the chamber body/shoulder juncture to the bolt face. When going to SAAMI measurements the first measurement as go-gage length would be 2.048, the field reject gage would be 2.058, then there is the no go-gage length that would be .004” longer than the go-gage length gage.

The Eddystone with the long chamber is not unseal, I have one that is .002” longer than a field reject gage. For me? Not a problem, I form 280 Remington cases to 30/06 with .014” added between the should of the case to the case head. The 280 Remington case is .051” longer than the 30/06 case from the shoulder to the head of the case. When forming I raise the die off the shell holder .014”, I verify the length of the case cases after forming.

Anyone that can verify the length of the case can verify the length of the go-gage or the no go-gage or the field reject gage.

Anyone that can verify the length of a gage or the length of a case from the datum/shoulder to the head of the case can measure the length of a go-gage etc. without a Hornady/Sinclair head space gage??? (comparator). I check the length of the M1917 chamber with a 280 Remington case, this method/technique allows me to to measure the length of the chamber in thousandths, meaning I do not need the go-gage, no go-gage or the field reject gage.

F. Guffey

[fguffey]

“Is that the final authority”

Final authority? I am not the AUTHORITY, I can correlate the dimensions of the chamber with the dimensions of the die with the gage. I have no problem verifying the dimensions of the gage with the case with the die.

Then there is the press, die and shell holder, because the press has threads that match the threads on the die a strong case can be made for it is safe to assume the die is adjustable. To reinforce this concept I form 280 Remington cases to chamber in the 30/06 chamber. I could mindlessly size the cases to minimum length, PROBLEM! minimum length is full length sized and is .005” shorter from the shoulder to the head of the case than a go-gage length chamber. To size the 280 Remington to 30/06 minimum length would require the shoulder on the 280 Remington to be erased and formed .051” behind the old Remington 280 shoulder.

And I ask: Why would anyone do that? With an elementary understanding of the incline plain (threads), when forming the 280 Remington to 30/06 the case will go through changes in length between the shoulder and case head, fist it gets to field reject gage length, if the shoulder is formed .004” further back it will become no go-gage length, after it passes no go-gage length it becomes minimum length.

If any thought is put into the process of case forming it should dawn on the reloader/smith the length of the chamber can be determined, in thousandths, without a go, no or beyond gage.

And as always there is the possibility of turning a go-gage in to a go to infinity gage. And it is possible to determine the length of a chamber in thousandths with a field reject gage.

F. Guffey

[Dollar Bill]

Forster SAAMI field gage reads 2.0577, so apparently the '03 and '17 gages are not interchangeable. You're correct about the stripped bolt==force of the striker spring on closing makes it tough to feel anything, especially subtle pressure. Without stripping the bolt on a BSA #4 Mk1, I would never have felt it "pass" when testing an Okie disc field gage, it was that close. I was stunned that it passed--first and only one of my Enfields that ever did.

I guess my overall question still is: with military rifles like the M1917/1903/SwedeM96/Kar98 and others with their greater tolerances, and mauser type actions with multiple locking lugs and gas holes in the bolt and receiver, how critical is one or two thousandths of an inch? And then of course there is the question of rimmed cartridges...oy vey!

:1948::1948::1948:

1903/A3 and 1917 gages are interchangeable.

The difference is that SAAMI gages read from the bolt face to the "datum", which is where the shoulder diameter is 0.375". Military gages, as noted in Hatcher's Notebook (page 237 in my copy), measures from the bolt face to the point the shoulder measures 0.4425". Different method of gaging.

There are different measurements, but only for Garand chambers. There, they allow an extra .002.

That said, the only gages I have are SAAMI gages. These are important to use in that any ammo produced with standard dies will be to that specification. Even military ammo. The thing is, military chambers generally are longer than SAAMI specs to allow for a wider variation in ammo and dirt/carbon/junk in the chamber. One of the worst examples (as far as handloaders are concerned) is the M60 chamber. Those chambers are so long they allow the case to stretch excessively vastly reducing the number of times the cases can later be reloaded.

In the end, the fact that your rifle fails the field gage is OK as long as it's only by .001 or so. You can measure how much by using .001 shims cut to fit the boltface. The thing to remember is that upon firing, your cases will stretch a little more than normal. This is not really, in itself, cause for concern. I would check that headspace measurement periodically, say once a year or every 1K rounds to ensure it's not getting worse. If it does, a gunsmith can set the barrel back one thread and ream the chamber to minimums.

If reloading your brass, you just need to be sure and set up your sizing die so it does not set the shoulder back more than about .002 from it's fired condition. You should still get about 10 reloads from those cases (LC or HPX, not commercial) before they have stretched to far, thinning the area just forward of the web and threatening a case head separation.

[swede49]

Thanks everybody. Thought this might turn out to be one of those "wished I'd never asked" threads!!

[fguffey]

Thanks everybody. Thought this might turn out to be one of those "wished I'd never asked" threads!!

That leaves me to assume you regret asking the question. I am not a fan of 'forced conformity of thought'. I said the length of the chamber for the 30/06 chamber in the M1917 could be checked with the field reject gage, I also said the 30/06 chamber could be checked with a 280 Remington case, I also suggested a reloader with a press, die and shell holder could determine the length of the chamber by forming cases with no more than basic skills and a good understanding of the incline plain.

Stripping the bolt, cock on close, then there is pulling the trigger to prevent cocking on close.

One more time, the long chamber in the M1917 is common, one smith was blamed for the long chambers, he used a field reject gage, his skills went beyond basic, his counterparts big egos would not allow them to ask: How?

F. Guffey

[chuckindenver]

again...
on 1917 and P14s.
they have a heavy camming pressure.
with no cocking assembly, and no extractor...
it is felt restance on the tool. even if it closes on the tool.. forester Gauges seem to be undersized....and i stopped using them years ago,, G.I. guages are best...
it is common for some 1917s to have over sized chambers...more so on winchester then any others...so bad on some that case head failure is common.
short sweet...no fancy figures.... weve beat this horse with a big stick so many times...its a tender steak.

[fguffey]

again...
on 1917 and P14s.
they have a heavy camming pressure.
with no cocking assembly, and no extractor...
it is felt restance on the tool. even if it closes on the tool.. forester Gauges seem to be undersized....and i stopped using them years ago,, G.I. guages are best...
it is common for some 1917s to have over sized chambers...more so on winchester then any others...so bad on some that case head failure is common.
short sweet...no fancy figures.... weve beat this horse with a big stick so many times...its a tender steak.
“forester Gauges seem to be undersized....” With minimum knowledge and skill a smith/reloader can measure a gage and verify the accuracy, if they had two they could compare the difference, ‘seem?'” is not a value, it is an opinion.

“ it is common for some 1917s to have over sized chambers...more so on Winchester then any others...so bad on some that case head failure is common” I have never found a Winchester with an excessive long chamber, the most common long chamber, in my opinion, is the Eddystone chamber. As reported before the Internet by smiths that built thousands of rifles from the M1917, they suggested the Remington first, then the Winchester, they they suggested to use caution when using the Eddystone, they claimed it was anyone's guess, at best it was hit and or miss.

Normally a very boring story for me stats when someone quotes Hatcher. “so bad on some that case head failure is common” On the first firing? Smiths and reloaders should stop and think before typing, The M1917 is a control feed Mauser like design, the extractor is in front of the the rim of the case, meaning to get case head separation when firing the rim would be forced to jump the extractor.

http://whisperingbooks.com/Show_Page/?book=Classic_Greek_And_Roman_Myths&story=Pegasus_Horse_With_Wings

or was it the Phoenix

Case head separation? No one measures before and again after, for the case to stretch when fired and separate between the case head and case body the body with the shoulder must move forward, problem, the case head head spaces on the extractor. Complicated for all and beyond the grasp of most, when a case is fired in the M1917 with additional chamber length the shoulder is erased and becomes part of the case body, the shoulder on the case when ejected is a new shoulder that was formed when fired.

No one scribes the case body/shoulder juncture before firing, I have fired 8mm57 ammo in a 8mm/06 chamber. that is .127” additional length added to the length of the chamber, if there was any truth to the claim “so bad on some that case head failure is common” I should have experienced case head seperation, instead I ejected cases that looked like 30/06 cases with very short necks.

Case head failure and case head separation are not the same. Case head failure can happen when the case experiences excessive pressure/failure.

No one scribes the case body/shoulder juncture, they assume the case stretches between the case body and case head, then there is the other factor, the design of the receiver and jumping the extractor.

F. Guffey

[Dollar Bill]

My goodness. Someone certainly is full of himself!

[fguffey]

[QUOTE=Dollar Bill;321595]1903/A3 and 1917 gages are interchangeable.

In the end, the fact that your rifle fails the field gage is OK as long as it's only by .001 or so. You can measure how much by using .001 shims cut to fit the boltface. The thing to remember is that upon firing, your cases will stretch a little more than normal. This is not really, in itself, cause for concern. I would check that headspace measurement periodically, say once a year or every 1K rounds to ensure it's not getting worse. If it does, a gunsmith can set the barrel back one thread and ream the chamber to minimums.

------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Bill Dollar, I will assume you missed the part about “the forced conformity of ideals”. I believe there is something very sick about the forced conformity of ideals.

It is possible there is/are elements you do not understand, again, I will assume you missed the part about the smith at the Utah arsenal that used a field reject gage to determine the length of the chamber. His critics did not ask him how he did it, they assumed he was doing it wrong.

“In the end, the fact that your rifle fails the field gage is OK as long as it's only by .001 or so. You can measure how much by using .001 shims cut to fit the boltface. The thing to remember is that upon firing, your cases will stretch a little more than normal. This is not really, in itself, cause for concern. I would check that headspace measurement periodically, say once a year or every 1K rounds to ensure it's not getting worse. If it does, a gunsmith can set the barrel back one thread and ream the chamber to minimums”

The length of the chamber can be measured in thousandths from the shoulder of the chamber to the bolt face without shims. Any wildcatter can form cases to fit a chamber from the shoulder to the bolt face, I will assume there is only wildcatter on this forum, I form 30/06 cases that are .012” shorter than minimum length, minimum length is .005” shorter than go-gage length. Going the other way I form 30/06 cases that are .020” longer than a minimum length case, that is .006” longer than a field reject chamber.

“The thing to remember is that upon firing, your cases will stretch a little more than normal” I fire new cases in a M1917 Eddystone that has a chamber that is .016” longer than minimum length or .002” longer than a field reject gage without stretching the case, again reloaders assume the case stretches between the case head and case body/


“012” shorter than minimum length” is .017” shorter than a go-gage length chamber, 012” shorter than minimum length is a short chamber.

F. Guffey

[Dollar Bill]

You assume way too much, sir. You are not telling me anything I don't know but, at the same time, not assisting the OP.

My apologies, swede.

[chuckindenver]

standard factory 30-06 case head failure taken from a Winchester 1917. with an over sized chamber.
every 1917 that iv ran into with headspace issues..was do to an over sized chamber or bolt set back
i have yet to find an eddstone or Remington with an over sized chamber.
most of those were do to bolt set back with wear on the locking weighs..
well, i havnt wrote or even read any of the books on 1917s...helped out a good friend on his though,..
however.
in the last 10 years.. personally...i have rebarreled and rebuilt well over 350 1917 Enfields.. maybe more if i really sat down and thought about it.
my comments are based on my own personal observations while working on the 1917. not based on info posted on the net, or by a book..
heck in the last 6 mos, iv changed barrels on well over 30 1917s ...
i dont need to post measurements...or quotes from books.... i can however provide pictures of a pile of crusty barrels iv pulled and replaced,..
and provide a list of very happy shooters...if need be...
sometimes...a guys got to put down the book, and turn off the net,..put some gloves on....and wrench on a rifle...
im ok if you dont agree..or dont like what i post.... i try and keep my answeres short and sweet, and easy to follow..

[fguffey]

chuckindenver, If I was selling Eddystones that is the way I would present them, before the Internet, the Eddystone had a reputation of being anyone's guess when it came to quality.

Bolt set back: if the bolt sets back where does it go? An expert on the M1917 will suggest checking the bolt handle contact, as you should know the M1917 does not have a 'third lug', the bolt handle is the third lug. If the bolt sets back the bolt handle supports the bolt or it shares in the support, and as you should know there is not a lot of room in front of or behind the bolt handles when fitted to the receiver.

Then there is the 'bucket of bolts mentality' when purchasing bolts, it is suggested, when purchasing bolts, purchase two or three etc., seems one day a reloader/smith would discover the effect the bolt has on off setting the length of the chamber can be measured.

Again, an old member of this forum was having trouble determining the length of the chamber in thousandths. I went over to load a Mill I purchases and while there I checked his chamber length with a feeler gage and the ammo he was going to fire. I verified the length of the chamber with one of his head space gages and a feeler gage. He had no less than 80 bolts, I had no less than 30 bolts for the rifle he was working on, I offered to check all of his bolts for their ability to off set the length of his chamber with out installing the bolt.

I knew none of my bolts would help him, in time he got help from a resource/collector.

F. Guffey

[chuckindenver]

bolt set back..
if you remove the barrel,
and look into the face of the action, you will see the locking lug ways..were the back of the locking lugs ride against the receiver.
the 1917 is 3.5% nickel steel, as is the bolt, both are only surface hardened.
with amount of camming pressure the 17 has, after time, the bolt wears through the way or weigh...on the receiver, setting the bolt back..
you can buy time with a new bolt, or use a USMC or K marked bolt as they were made of 8620 steel and run smoother, and tend not to gual the steel.
however...this usually death for the receiver..

[fguffey]

"You assume way too much, sir"

I appreciate this approach more than I appreciated the"

"My goodness. Someone certainly is full of himself!"

In the beginning there was a drawing illustrating a case with a line through the shoulder area of a case, with an arrow pointing to the line and the caption, "Datum line", then the total amount of information in the description claimed "And that is how they do it".

The datum was not a line, it was a round hole/circle, with all the space used when posting the illustration there was never mention of the diameter of the datum or the distance from the datum to the head of the case, even today the case has a length measured from the datum to the head of the case but the case does not have head space, the case has a length that off sets the length of the chamber.

If I assume too much? I can not disagree, I assume collectors/reloaders/smiths are capable of understanding the concept.

Perception in my assuming, there are members that do not know and or understand and they do not want anyone else to understand.

F. Guffey

[chuckindenver]

you can see all the measuring and high tech work that went into making a 1917 barrel....this short film puts a nother spin on the over all.
http://www.criticalpast.com/video/65675063737_ordnance-material_rifle-bars_trigger-guards_gun-barrels_look-through-periscope

[fguffey]

Chuckindenver, not easy to respond, you changed/edited your post, I ask about the set back bolt, "Where does it go? Back? When the bolt moves back what does it hit?, What stops the bolt from moving back?

F. Guffey

[chuckindenver]

bolt set back..
if you remove the barrel,
and look into the face of the action, you will see the locking lug ways..were the back of the locking lugs ride against the receiver.
the 1917 is 3.5% nickel steel, as is the bolt, both are only surface hardened.
with amount of camming pressure the 17 has, after time, the bolt wears through the way or weigh...on the receiver, setting the bolt back..
you can buy time with a new bolt, or use a USMC or K marked bolt as they were made of 8620 steel and run smoother, and tend not to gual the steel.
however...this usually death for the receiver..

you missed it...sometimes you have to log out and log back in..

[chuckindenver]

a picture for your veiwing pleasure..
as you can see. the ways are worn through the hardening...it was really time to retire this ol girl..

[chuckindenver]

bolt set back is the most common issue with 1917,s and P14s..and if this bad...a killer.. just a matter of time before a load of hot gas is blown in the shooters face.
please keep in mind..
most of the reader on this and other sites..are average shooter hobbiest collectors, just a regular Joe with a attraction to old rifles...
sometimes a basic simple answer is really all thats needed to help...
i too get to long and drawn out and have to catch myself...i remember to make it easy to read and understand.

[oldtirediron]

This subject has been bouncing around since at least 1946-- You can read about it in Hatcher's Notebook and If I remember correctly they reamed a 1917 out to some monsterous oversized condition and the rifle still shot and sometimes the accuracy even increased! if it were my rifle I would disassemble the bolt clean the chamber, receiver, bolt bearing areas and the bolt-- Then I would check the headspace and see what it reads!! Next step I would try and get a new bolt and check the headspace with that one-- Next step?? all depends!! Most of these rifles are fixed rapidily with a new bolt---I think a lot of these rifles are and are being messed with by people Matching up the parts!! The military armorer didn't care who made the part-- just as long as it worked!

[fguffey]

This subject has been bouncing around since at least 1946-- You can read about it in Hatcher's Notebook and If I remember correctly they reamed a 1917 out to some monsterous oversized condition and the rifle still shot and sometimes the accuracy even increased! if it were my rifle I would disassemble the bolt clean the chamber, receiver, bolt bearing areas and the bolt-- Then I would check the headspace and see what it reads!! Next step I would try and get a new bolt and check the headspace with that one-- Next step?? all depends!! Most of these rifles are fixed rapidily with a new bolt---I think a lot of these rifles are and are being messed with by people Matching up the parts!! The military armorer didn't care who made the part-- just as long as it worked!
There was situation One, situation Two. The assumption, head space causes case head separation, problem: No one doing the test knew what they were looking for. The shoulder was moved forward .080”, the difference in length between the chamber length and case length was .085”, when fired the shoulder of the case did not move, it was erased when a new shoulder was formed. How would they have know? Hatcher and his crew could have scribed the shoulder of the case before firing and then again after firing.

Scribing: If the case had been scribed at the case body/shoulder juncture they would have knew the case did not stretch between the case head and case body. They would have know the case did not stretch ‘period’, had they scribed the case body/shoulder juncture they would have know part of the shoulder became part of the case body and part of the neck became part of the shoulder. The case head spaced on the extractor. There are other receivers that do not have the Mauser type extractor. I have fired 8mm57 ammo in an 8mm06 chamber, that is .127” difference in length between the chamber and ammo, I ejected 8mm06 cases with very short necks, meaning most of the shoulder became part of the case body and most of the neck became part of the shoulder. I could have used a different receiver without the Mauser claw, meaning another extractor of a different design may not hold the case.

Changing bolts, I have no less than 40 Springfield bolts, I do not find it necessary to switch/change bolts to determine the effect the bolt will have on the length of the chamber, the effect the bolt has on changing head space/length of the chamber can be measured and compared with the bolt that has been removed. I have 12 M1917 bolts, with 2 exceptions 10 of the bolts will not change the length of the chamber .001”, the two exceptions are bolts that have been opened for magnum belted cases.

The M1917 does not have a third lug like the Springfield or Mauser, the bolt handle is the safety lug, when checking for bolt set back I check the clearance behind the the bolt handle. Checking the clearance is possible, if the clearance is measured bolt set back can be tracked.

F. Guffey