Learning Curves

Discussion in 'Curio & Relics Forum' started by cointoss2, Mar 4, 2003.

  1. cointoss2

    cointoss2 Guest

    TallTLynn
    Senior Chief Moderator Staff
    Posts: 3001
    (1/27/02 1:18:43 pm)
    Reply | Edit | Del All Learning Curves
    --------------------------------------------------------------------------------
    My learning about these old rifles has been a hard one. It's taken me over 2 weeks to figure out why I couldn't get the bolt to stay in the closed position in my Enfield. After four hours of going over and over and over things again with the bolt and the like I have figured out one thing for sure. Both bolts from both Enfields will interchange. Both take a little bit of force to stay in the shut position. But that's all it is - a little bit of force.

    Something I will now never forget.

    By the way does anybody know the difference between a #1 bolt and a #2 bolt? Just curious.
    TLynn

    Xracer
    Senior Chief Moderator Staff
    Posts: 1544
    (1/27/02 6:02:20 pm)
    Reply | Edit | Del Re: Learning Curves
    --------------------------------------------------------------------------------
    I thought "Learning Curves" was what I did as a teen-ager studying "Anatomy By The Braille Method"!

    HondoJohn6508
    Member
    Posts: 35
    (1/27/02 8:17:55 pm)
    Reply | Edit | Del Re: Learning Curves
    --------------------------------------------------------------------------------
    TLynn,
    'MAY THE FORCE BE WITH YOU TODAY,TOMORROW,ETC.!



    Sorry about that, I just couldn' resist!!!!

    Ol' John in Hondo!




    Moskovskyya
    V.I.P. Member
    Posts: 81
    (1/27/02 10:28:43 pm)
    Reply | Edit | Del Re: Learning Curves
    --------------------------------------------------------------------------------
    I'm not much of an Enfield guy, so I don't know the exact length, but the #2 bolt head is something like (for instance) .002 longer than #1, there is a #3 for example that is somewhat longer yet. The different lengths are for headspace adjustments.

    polishshooter
    Senior Chief Moderator Staff
    Posts: 2697
    (1/28/02 1:53:03 pm)
    Reply | Edit | Del Re: Learning Curves
    --------------------------------------------------------------------------------
    I'm not sure of the headspace adjustments...the headspace is determined by the rim thickness, so it is tough to adjust much...awfully hard to screw up headspacing on a rimmed cartridge, which is why MOST early (Late 19th Century) military bolt action designs used them...it's not until they invented machine guns that the disadvantages of the rimmed round showed up...but that's why I prefer rimmed rounds in the old guns...at least when I shoot them.

    BUT there are two types of bolt heads on early No. 4s vs later No. 4s because they did away with the seperate bolt release lever on the later ones...the bolt head is what kept it in the reciever.

    And the No.1 MkIII had a different bolt head altogether, with a retaining spring that kept it in the reciever...
    We must make war as we must; not as we would like. - Field Marshal Kitchener, 1915

    TallTLynn
    Senior Chief Moderator Staff
    Posts: 3014
    (1/28/02 10:34:56 pm)
    Reply | Edit | Del Re: Learning Curves
    --------------------------------------------------------------------------------
    polish - two No 4's Mark I's. One has a #1 bolt, one has a #2 bolt. From the way I've been able to interpret how things work - it sure looks like both will work in either gun.

    The guns are also both the same year. The only way besides the number to tell them apart is star patterns on the underside of the bolt from the Longfield Enfield that I've had forever. It's the #1 bolt. I don't know where the Enfield that Bob sold me came from - it doesn't say on the rifle itself but both rifles are the same year.

    Now as for headspacing - would someone tell me what exactly that means???
    TLynn

    Doctor Xring
    Member
    Posts: 11
    (1/28/02 11:32:13 pm)
    Reply | Edit | Del Re: Learning Curves
    --------------------------------------------------------------------------------
    Headspace is the "maximum allowable distance" between
    a defined point on the chamber and the face of the bolt
    when it is in the closed position (as in when a round is
    chambered).

    On a rimmed cartridge weapon, like the .303 British for your Enfield, it would be the distance between the bolt face and the front of the recess for the rim of the cartridge. On
    a rimless bottle neck case, like your 30-06 it is the distance between the bolt face and the datum line on the shoulder of the chamber (where the main part of the case forms the
    shoulder on the case, right before the neck where the bullet
    is held).

    This distance is important because if the "headspace" is
    too short, you will not be able to chamber the round.
    If it is too long, then the case may rupture due to stretching
    and elongation of the brass case upon firing.

    It is checked with metallic guages machined to the proper
    tolerances for acceptable ranges.

    Hope this helps !!

    best, DXR

    TallTLynn
    Senior Chief Moderator Staff
    Posts: 3021
    (1/28/02 11:46:29 pm)
    Reply | Edit | Del Re: Learning Curves
    --------------------------------------------------------------------------------
    Thank you sir. It makes sense though I admit I'll have to read it two or three times to totally sink in.

    Looks like I need to go borrow my ex's tools. Thank god we're friends.
    TLynn

    Doctor Xring
    Member
    Posts: 12
    (1/29/02 12:01:07 am)
    Reply | Edit | Del Re: Learning Curves
    --------------------------------------------------------------------------------
    Hi Lynn --

    I'm still learning too. :)

    Could you tell me how to post pictures on this forum ?

    Also -- this is a good link that discusses headspace.
    It's one of those simple things that is hard to describe.
    Sounds much more complex than it is !

    www.geocities.com/swede94/handvapen.html


    dxr

    cschwartz@satx.rr.com

    Edited by: bondai at: 1/29/02 12:11:13 am

    TallTLynn
    Senior Chief Moderator Staff
    Posts: 3023
    (1/29/02 12:18:53 am)
    Reply | Edit | Del Re: Learning Curves
    --------------------------------------------------------------------------------
    To post pictures first you have to have a host site to put them on (web site that is).

    Then all you do is copy where they are at and put [ i m g ] in front and [ / i m g ] afterwards. No spaces though (I had to put them there so they would show up).

    Hope that helps. And thank you for the web site to read some more on head spacing.
    TLynn

    Doctor Xring
    Member
    Posts: 13
    (1/29/02 12:22:58 am)
    Reply | Edit | Del Re: Learning Curves
    --------------------------------------------------------------------------------
    cool - thanks !

    I'll give it a shot.

    Moskovskyya
    V.I.P. Member
    Posts: 88
    (1/29/02 2:02:22 pm)
    Reply | Edit | Del Re: Learning Curves
    --------------------------------------------------------------------------------
    Polish, Xrings def of head space is perfectly correct! Again, I'm not much of an Enfield guy, I only have 4, but my bud is. I have a #1 that he checked out for me, and he said that the locking lugs had "set back" in the receiver slightly causing excessive headspace. The only way to repair was to use a longer bolt. He installed a #2 bolt head and checked head space again, problem solved. As far as the Enfield, installing a longer bolt head is a neat trick. Imagine a Mauser rifle, you would have to thread the barrel, for one more turn, and shorten to fix excessive head space.


    polishshooter
    Senior Chief Moderator Staff
    Posts: 2702
    (1/29/02 7:19:56 pm)
    Reply | Edit | Del Re: Learning Curves
    --------------------------------------------------------------------------------
    Stupid question, what are the chances the bolt heads got changed somewhere along the way and you actually just changed them back?

    "Set back" is a condition that many people have heard about, but few have seen, I know I never have...but I've heard people talk about it, usually in big belted magnums, if I remember right...

    Headspace REALLY isn't that hard to explain, Doc is correct, but sounds like a darn SAAMI engineer...

    All it is is how the round is indexed (positioned) in the chamber...where it is when it's in the designed position to be fired...the bolt pushes it from the rear, and it is measured from there to whatever it is designed to push against in the chamber, only one of four things, Rim, belt, shoulder, or case mouth...

    Bottom line is, rim and then the belts are the most foolproof, as that area of the CASE rarely changes, at least in length...in other words the CASE usually doesn't cause headspace issues, and that area is not normally subject to erosion, whether from gases or wear, i.e., something must happen to the bolt or chamber to mess the headspace, and if somebody doesn't screw with the bolt, USUALLY never is an issue...BUT rimless, and especially straight walled cases, the CASE can cause headspace issues, normally because they stretch when fired, and must be trimmed, and can be trimmed too much...plus the shoulder is the weakest area of the case...and the throat and front of the chamber can erode and wear pretty rapidly...

    GEEZ, I tried to keep it simple and wrote a book TOO! Oh well...

    And the simple explanation Doc gave is true too...too little, the gun won't work, too much and the gun can blow up... (or at least split the case which is why you always wear shooting glasses always, (redundancy intended...)especially shooting the old rifles, because that superheated gas IS going somewhere, possibly back through the bolt right in your eyes...)

    It happened to my bro-in-law and a Carcano carbine, and I was watching when it happened...eyebrow was SMOKING...LOL...but he had glasses, so we can laugh about it now and bitch at Italian crap, but it wouldn't have been funny if he wasn't wearing glasses...

    But unless a rifle has been fired ALOT, like competition or training Garands were, there usually is not that big a problem with headspace...

    It becomes critical though with machine guns, which have adjustable bolts in most cases, that must be constantly checked and adjusted...mainly because chamber dimensions change so much from the extreme heat from extended firing...set it tight when the barrel/chamber is hot, and when the gun cools, it won't feed...set it loose when it's cool, and when it heats up and expands it may blow...

    My theory is anybody who was in the military, and was trained on or was exposed to machine gun headspacing, or ever witnessed or heard stories of a Watercooled Browning 1917, or a M2, or an M60, that blew up, becomes "hypersensitive" about headspacing in any gun, and adds to the "hysteria" about it...


    We must make war as we must; not as we would like. - Field Marshal Kitchener, 1915

    TallTLynn
    Senior Chief Moderator Staff
    Posts: 3025
    (1/29/02 7:43:37 pm)
    Reply | Edit | Del Re: Learning Curves
    --------------------------------------------------------------------------------
    No polish - that was the first time I took the rifle out - that's when I realized I had the wrong bolt in the wrong rifle.

    The one BobinStLouis sent me has a lot more gunk in it (as in oil or cosmoline or something) than the one I already had. Plus the bolt for my Longbranch is far shinier than the other one.

    It all seems to boil down to that one part of the bolt that you can unscrew. Screw it out too far and it won't shut, screw it in too far and it won't lock. Guess it had just been screwed out a bit much when I didn't realize that they did unscrew (which is pretty amazing considering I've owned the one Enfield for over 8 years).
    TLynn

    Moskovskyya
    V.I.P. Member
    Posts: 95
    (1/29/02 9:31:31 pm)
    Reply | Edit | Del Re: Learning Curves
    --------------------------------------------------------------------------------
    hey polsih, you're right about "set back" most peope have never seen set back. Thats really general term, but basically, the bolt is the easier to replace in a rifle, than the receiver. "No kidding", for that reason the bolt is somewhat softer than the receiver. Further, if the locking lugs wee too hard, they would be more likely to break, and we wouldn't want that! What happens is that firing the weapon after a little chamber wall wear will allow the cartridge case to slam to the rear against the bolt face. This hammering over a period of time will "flatten" the rear of the locking lugs where they contact the harder reciever, there by making more space between the case head and bolt face, (excessive head space). If that space is excessive enough, that the case cannot obturate, you will have gas expelled into the reciever, and possible case failure. A longer bolt, or longer barrel will solve the problem.

    Another way to semi solve the problem, is to reload the cases fired in the rifle with the excesive space, with neck sizing only. The cases fireformed to the large space and will fit the second time around.


    polishshooter
    Senior Chief Moderator Staff
    Posts: 2703
    (1/30/02 12:01:32 am)
    Reply | Edit | Del Re: Learning Curves
    --------------------------------------------------------------------------------
    Hey, Mosko, or anybody...now that we are on the headspace tangent, how do YOU test a new weapon, assuming no access to a go-no go guage?

    I use the "Polish Headspace Test" on my Nagants, but would never do it with a rimmed round, or an action I didn't trust...for that I would use a variation of it( see below ) but I HAVE done it with an 6.5 Arisaka and a Steyr M95 too...

    First, I cycle a stripper clip of ammo through it without firing, just to test function and chambering. Insufficient Headspace would be apparent at this time. I have NOT found this condition yet, thought I did when one chambered hard, but it was a bent extractor that also had a burr...then...

    I single load one round, hold it down and away, tilt it away as much as I can, point it downrange at a good backstop (A dirtpile in my backyard), close my eyes, turn my head and cough, and touch it off.

    Then I CLOSELY inspect the fired case for primer extrusion and/or flattening if any, and bulging in the case immediately ahead of the rim.

    If I find nothing, (And I haven't yet, and I've done this on at least 25-30 various MNs so far...) I repeat about 5 times, if nothing, then I bang away.

    If I get any rimless or semi-rimmed weapons, though, I think I will use the "Tie it to a Tire and use a String" variation of the "Polish Headspace test..."

    I guess I'll have to track down a guage someday to look like an expert, BUT I don't think my method is unsafe at all, at least with Nagants or other rimmed round actions....
    We must make war as we must; not as we would like. - Field Marshal Kitchener, 1915

    Moskovskyya
    V.I.P. Member
    Posts: 96
    (1/30/02 7:25:27 am)
    Reply | Edit | Del Re: Learning Curves
    --------------------------------------------------------------------------------
    Polish, I use the "Poor Russian" method that sounds a lot like your polish method! After said methods being used, I have double checked with unfired case with shim glued to the head, and tripple checked with Clymer head space guage, and have found that Polish / Russian methods work fine. I personally believe, that a spent case is a much better indicator of the overall condition of the firearm.

    Above what you are doing, I could only recomend a couple of things, #1, fire the first round from the tire. Its not really likely, but if you had a problem firing, when holding the piece with "head turned", the back / side of the head is almost as important as the front. #2, (you didn't indicate, but you probably already do this one) use brass cased test ammo rather than this steel cased surplus stuff. The steel surplus ammo won't give like brass and may obscure faults in the mechanical condition.

    As a note, I got one of those Romanian "INSTRUCTIE" M91's in a 5fer a while back. With a round chambered, you could hear it rattle in the worn chamber / set back bolt! When tirefired, the firing pin knocked the round up in the chamber so far that the pin was to short to detonate. The rifle was rusty and worthless, so I decided to make an "EXPLODED VIEW" display of a Mosin Nagant. I twisted the firing pin adjustment in 3 or 4 turns, and I loaded a round FULL of Bullseye, and used all the crimp I could get! I called the round a chamber bomb. I setup in the tires, (X2) covered with old carpet for a schrapnell shield, gave a "fire in the hole" warning and yanked the string from behnd the oak tree. Eager to retrieve my display pieces, I removed the shield, NO DAMAGE, damnit! I repeated the chamber bomb 4 more times, and the old girl is still intact. I polished her into a non firing parade rifle and she still hangs on the wall today. I may not be possible to blow up one of these babies without plugging the barrel, I don't know.


    the real fredneck
    V.I.P. Member
    Posts: 788
    (1/30/02 8:26:15 am)
    Reply | Edit | Del Re: Learning Curves
    --------------------------------------------------------------------------------
    a rifle case full of Bullseye would be considered a "high velocity" cartridge wouldn't it?

    Moskovskyya
    V.I.P. Member
    Posts: 99
    (1/30/02 9:53:44 am)
    Reply | Edit | Del Re: Learning Curves
    --------------------------------------------------------------------------------
    Yes it is, for sure! Probably the reasen it didn't suffer the old catastrophic receiver failure, is that the bore is most likely worn to the point where there was on seal by the bullet.


    polishshooter
    Senior Chief Moderator Staff
    Posts: 2704
    (1/30/02 1:30:51 pm)
    Reply | Edit | Del Re: Learning Curves
    --------------------------------------------------------------------------------
    I don't know, but I have NEVER heard of a Nagant blowing, have you?

    It may not be as strong as say an Arisaka, but it sure LOOKS strong.

    And considering the millions upon millions of illiterate peasants that have used these over the past Century, where the proper cleaning technique was to at the company level, for 50-100 soldiers to throw all the bolts and other parts into big barrels of solvent or boiling water, then pull parts as needed to build "a" rifle back out when they were clean, with NO effort to match bolts/trigger groups to recievers, and there are NO reports of blow-ups...I'd have to say they are pretty strong as well as "peasant proof."

    Plus, there are stories of US made rifles not functioning in the cold during the Allied Archangel expedition in '19, that was solved by simply replacing the tight US made bolts with captured worn Russian ones willy-nilly, I'm not sure headspace with them REALLY is an issue...

    We must make war as we must; not as we would like. - Field Marshal Kitchener, 1915