Head Space and the 1917

[milboltnut]

incipient definition is beginning stages..... you would see stretch marks on the outside with all that "headspace"


the second pic to the right is the outcome of excessive headspace.... and it's up to you to figure out what makes the girl roll backwards on her skates.

http://www.qrg.northwestern.edu/projects/vss/docs/media/Propulsion/basketball.gif

[fguffey]

are you gonna answer my question.... or feed me a bunch of hoopla?

That was rude, I did not expect you to say anything like; 'thank you".

I said nothing about how far I believe you have to go before you can understand the answer.

I knew that when you starting with the moving the shoulder forward.

F. Guffey

[RC20]

I never said I would grind bolt lugs. Hatcher was saying that's what would increase HS, if bolt lugs were ground. Cutting chamber further down the barrel would not effect HS.

While grinding lugs does increasing head space.

Chewing the chamber deeper also does.

As the key element is the shoulder that the cartridge rests on if momentary when fired, if that goes deeper then the case will expand to meet it (if it can) and more importantly, the distance from the bolt face to the chamber shoulder datum point (as will the whole shoulder) will be longer and that is the definition of head space.

A lot is missing that has been removed or does not show up.

Longer heads space of itself does not cause a case to bust. It just stretch it. 303 is a case in point, unless you do minimal shoulder bump back or neck size, it will break a case in about 3 firings.

It may or may not fire if the extractor does not hold the head tight to the bolt.

Normally the 1917 has more head space than a SAMI made to spec rifle does. Its a combat rifle, SAMI did not exist then. Keep the same cases and minimum shoulder bump back and its not an issue.

Again worst case it does not fire, if it fires it fire form to the chamber (with some drop back as it contracts after firing)

[fguffey]

While grinding lugs does increasing head space.

I would suggest: If you have a M1917 examine it, take notes and it helps if you are able to compare the M1917 with other designs like the 03.

F. Guffey

[fguffey]

While grinding lugs does increasing head space.

and then I responded with

I would suggest: If you have a M1917 examine it, take notes and it helps if you are able to compare the M1917 with other designs like the 03.

If you do not have a clue as to what I am talking about I recommend you do not mess with the lugs. I have heard the M1917 bolt arrangement is the most strongest in the world, I believe that is nice to know but I want to know about clearance.

I have a M1917 with a chamber that is field reject length + .002", that is .011" longer than a go-gage length chamber. What? Me Worry? I off set the length of the chamber with the length of the case from the shoulder of the case to the case head.

F. Guffey

[RC20]

I simply put a fact down, grinding the lugs does increase head space

Its a really bad thing to do as it allow movement on the bolt and that is a bad thing.

As noted, fire the round, measure it at shoulder , set it back the minim opf .003 to .005 and its no longer an issue.

Its not a case you can use in most 06 rifles, so you segregate.

All the rest if fluffy hoopla.

Don't make it any more complicated than it needs to be to work.

are you gonna answer my question.... or feed me a bunch of hoopla?

Mr. G is in love with his hoopla. I think it allows him to feel superior when all he does is make the issue as hair splitting as the best attorney in pursuit of that.

Some of us try to keep it no more complex than needed, we don't need the underline physics, just how to deal with it successfully.

As a 1917 shooter I have done so.

[fguffey]

I simply put a fact down, grinding the lugs does increase head space

And I simply asked you if you owned a M 1917 and then I asked if you owned one would you examine it and then compare the action with another action.
You have spe3nt a lot of time talking about the M1917 and the chamber. From your explanations I have to draw the conclusion there are no good ones. And then there are sources, you never list one, this leads me to believe you are the expert. That brings us back to the question about owning a M1917. You talk about grinding the back of lugs like you do it everyday. I have never found it necessary to grind the back of the lugs for any reason, but! if I did grind the back of the lugs I know that would be the beginning of another problem.

And then there is the head space gage: You have spent a lot of time talking about wrecking the head space gage. The head space gage is solid and made of good material. Arsenal gun smiths never considered crushing a head space gage by closing/forcing a bolt closed on one of them. They got real tacky with one smith, they did not understand what he was doing or how he was doing 'it'. The important thing? He did not care what they thought and the fact they did not understand what was going on did not upset him. All of this went on 70+ year ago. When he was checking rifles it did not take him long to look at them.

F. Guffey

[RC20]

Well when your minds thoughts resemble a pretzel then you of course are going to be confused as you cross over your previous thought and you never know which way its going to turn.

Just to clarify, I never said I grind down lugs, nor did I suggest it was anyting but stupid idea, all it did was convey that doing so is close to if not criminally dangerous. Hopefully that is clear enough?

And you know I own 1917s. (don't ask how many I won't tell you).

And your conclusion is there are no good ones, not mine.

For anyone else, they are fine. They are long on head space per SAMI but its not an issue though reloading procedure is best done with dedicated brass. They are potentially DANGEROUS guns as they have unsupported heads and a gas blowout wold be an ugly incident fore the shooter. Also clear?

As for head space gauges, yes they are steel. At issue is you can't feel the free action of closing if the striker is in the bolt. As its an iffy end of Field Reject, getting the striker out (which is easy) allows for that fine feel.

What some guy was doing 70 years ago is not relevant to me in the least. Some understood the guns and some did not and do not and we have good current knowledge and procedures for working with them. Bad info was bad info back then as it is now. The caliber being 303 was one that still exists.

[JOHN COOK]

RC20, you know you won't get the last word on this subject.. Don't make Mr. fguffey pull out his feeler gauges, if so , it will be an open and shut case, or an open and shut bolt, or what ever. You will be wrong in his opinion.Don't have a dog in this scenario but enjoy the commits..

john in SC

[fguffey]

For anyone else, they are fine. They are long on head space per SAMI but its not an issue though reloading procedure is best done with dedicated brass. They are potentially DANGEROUS guns as they have unsupported heads and a gas blowout would be an ugly incident fore (for) the shooter. Also clear?

Long before me Hatcher carried out experiments on case head separation, He decided to use the M1917 in one of three situations, when finished the conclusion of his experiments/testing proved there was no way the chamber could be long enough to cause case head separation. He increased the length of the chamber from the shoulder to the bolt face in increments. Legend has it he advanced the shoulder .060" beyond go-gage length. Hatcher could have explained the effect the long chamber had on the case when fired; the shoulder of the case did not move, the shoulder of the fired case became part of the case body; the new shoulder of the fired case was formed from part of the shoulder and neck. As a result of the fire forming the case got longer from the shoulder to the case head and shorter from the end of the neck to the case head.

I said the shoulder of the case when fired did not move; the shoulder/case body juncture did not move. I can do nothing about the reloaders infatuation with moving shoulders, reloaders insist they can move the shoulder by bumping (?) they insist the shoulder moves back when full length sizing. I insist it is impossible to move the shoulder back with a die that has case body support.

What feed back do I get from reloaders? I could get more civil responses from children.

Again: I chambered 3 Mausers to 8MM06, when I started the chambers were 8MM57. I went to a firing range and fired 8MM57 ammo in the 8mm06 chamber. The difference in length between the chamber and ammo when measured from the shoulder to the bolt face and case head was .127”. For those that can keep up that is twice as much clearance as Hatcher had with the M1917. When I ejected the cases I knew what effect the chamber had on the case when fired. One more time: The shoulder on the fired case did not move, the shoulder became part of the case body and the neck of the 8mm57 became part of the shoulder on the 8mm06 case. The case had a hint of a neck.

Same thing only different: A friend built 4 magnificent rifles, he made the reamer, and he made the die (and magnificent dies they were), he did the bluing and carved the stocks, a most talented individual with skills beyond etc. etc.

After building the first rifle he went to the range to test fire; he had 5 case head separations out of the first 10 cases fired. I suggested I could have tested the rifle before he headed for the range and I told him I could have ‘fixed it’ before he left for the range. I also suggested I could have formed his cases before he fired them.

He broke the reamer, how I do not know but that was the end of his building 270 Wildcat improved based on the 30/06 case and very similar to the Gibbs chamber.

I did not have case head separation with my Mausers, I did not have case head separations with my M1917s. He did not use the Mauser action; he did not use the M1917 action for his builds. He used handpicked 03s and 03A3.

When Hatcher was doing his experiments he used Category 1, Category 11, and Category 111.

F. Guffey

[RC20]

RC20, you know you won't get the last word on this subject.. Don't make Mr. fguffey pull out his feeler gauges, if so , it will be an open and shut case, or an open and shut bolt, or what ever. You will be wrong in his opinion.Don't have a dog in this scenario but enjoy the commits..

john in SC

Oh god, not the feeler gauges. then comes transfers and standards. Arrrgghhhhhhhh, doomed, doomed.

[fguffey]

Oh god, not the feeler gauges. then comes transfers and standards. Arrrgghhhhhhhh, doomed, doomed.

RC20, you know you won't get the last word on this subject.. Don't make Mr. fguffey pull out his feeler gauges,

A member of this forum built a period correct rifle; problem, the chamber could not be measured with a head space gage or A no go-gage or a field reject length gage by any member on this forum with the exception of one. He can measure the length of the chamber with a fields reject length gage and he can measure the length of the chamber with a no go-gage length gage and he can measure the length of the chamber with a go-gage length chamber. AND he can measure the length of the chamber without a chamber length gage.

Back to the 03 Rock Island period correct 1911 rifle. The builder of the rifle had all he could stand when it came to 'help from this forum'. No one would shut up long enough for the man to get help.

I went to his shop for a different reason when he explained to me about the difficulty in finding help with answers on the Internet. He explained to me he had 20 head space gages for the 30/06; problem, he did not have a head space gage that would indicate the length of the chamber from the datum to the bolt face. I explained to him measuring the length of the chamber from the datum to the bolt face was easy. I measured the length of his chamber and found it was .0025" longer than a go-gage length chamber.

Next? He wanted to correct the length of the chamber to go-gage length. I assured him he did not have a bolt that would correct the length of the chamber even thought he had 100+ 03/03A3 bolts. I reminded him I had 35 new replacement bolts from old stock, I told him I did not have a bolt that would correct the length of his chamber. I suggested he size/form his cases by increasing the length of the cases from the shoulder to the case head by .0025" or go for the magic .002 clearance. Problem, he was going to sell the rifle and the buyer wanted a go-gage length chamber.

Oh god, not the feeler gauges. then comes transfers and standards. Arrrgghhhhhhhh, doomed, doomed.

Again, he wanted to know the length of his chamber from the datum to the bolt face and he had 20 head space gages. I checked the length of his chamber without a head space gage. I also offered to modify one of his gages to something useful, he was afraid he would loose money on the gage.

F. Guffey

[RH Scott]

I think the best advise I found on checking headspace is "go light and if the safety will not engage, the bolt is not closed and your HS is good with that gage."

[fguffey]

"go light and if the safety will not engage, the bolt is not closed and your HS is good with that gage."

'THAT GAGE' ? What gage? Reloaders are familiar with 3 gages; they are aware of the go-gage, no go-gage and the field reject length gage. I make 12 gages that are shorter than the minimum length chamber, that is .005" shorter than the go-gage length chamber. I make gages that are +020" longer than the minimum length/full length sized case when measured from the shoulder/datum to the case head. reloaders have head space, I have clearance. And then there are reloaders that insist they have case head space; SAAMI says my cases do not have head space. SAAMI says the chamber has head space.

I measure the length of the chamber from the datum/shoulder to the bolt face in thousandths; I have one M1917 with a chamber that is .002" longer than a field reject length chamber. If I fired a full length sized/minimum length case in that chamber I would have .016" clearance.

F. Guffey

[lyman]

I think the best advise I found on checking headspace is "go light and if the safety will not engage, the bolt is not closed and your HS is good with that gage."

not so sure on that advice