Head Space and the 1917

[milboltnut]

reloaders do not understand or know what effect the chamber has on the case when fired.

https://i.imgur.com/1v6RxHb.png

Do you see any incipient case head separation?



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most reloaders and others alike really don't know why you get a case head separation... they really don't.

I had them in a 03... once and replaced the bolt and they went away.

[fguffey]

http://3.bp.blogspot.com/-8-g15CMR3L...1600/006-1.JPG

Do you see any incipient case head separation?

This is not the first time I have seen a 308 W case that was fired in a 30/06 chamber. Their was a member on this forum that claimed the 308 W was a small version of the 30/06; he impressed a lot of members by posting a picture of a 308W case chambered in a 30/06 chamber. And that is all he had to convince the crowd.

The 308W cases is .014" larger in diameter than the 30/06 chamber at the 308 W case body/shoulder juncture; meaning the 308W head spaces on the case body/shoulder juncture. When a 308W round is fired in 30/06 chamber the case is ejected with no neck and very with almost no shoulder.

Some shooters have shot M1 Garands with 308 W ammo; they claimed it shot 'quite nicely'.

I have 3 rifles that are chambered to 8mm/06; I have shot 8mm57 ammo in my 8nn06 rifles. The difference in length from the shoulder to the case head for the 8mm57 and 8mm06 is .127". After firing the 8mm57 in the 8mm06 chamber I ejected what looked like 30/06 cases with no necks and almost no shoulders.

AND! I have a M1917 that has been with us since the controversy began. The chamber has .016" clearance meaning the chamber is .002" longer than a field reject length gage, that also means it is .011" longer than a go-gage length chamber.

Your picture has nothing t do with case head separation.

F. Guffey

[milboltnut]

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

[milboltnut]

you win..... moving on

[lyman]

you won' t see any case head separation in that pic unless it is about to happen,

it is my understanding, and experience, that the separations start on the inside , and you can feel them with a scribe or paperclip with a bent end,

I have had several cases of questionable brass (as in no idea of rounds loaded or what shot thru) that you could feel the line on the inside,

cases were tossed,

[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/proj...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