cking Posted July 9, 2006 Share Posted July 9, 2006 I went and got out my US army drawings reprint. So Yes it is tilted to match the barrel but also to help feeding? That's my guess. Lets here more. Don't be locking these thread when there is good stuff going on. Link to comment Share on other sites More sharing options...
eric nielsen Posted July 9, 2006 Share Posted July 9, 2006 Because the barrel points down [about] 1 degree relative to the rails of the slide. That's at full lock-up. Don't know the angle when the gun is feeding a round from the magazine. Maybe 2deg up?? Link to comment Share on other sites More sharing options...
shred Posted July 9, 2006 Share Posted July 9, 2006 If anybody happens to be around Ogden UT with some free time, or has the slightest chance of making some, go by the JMB Firearms museum. It's well worthwhile. If you bring a machinist along, have them tell you about the accuracy of the tools JMB had to work with, and you'll get a whole new understanding. As Eric says, since the barrel's cammed over at full lockup, you need clearance somewhere so the hood can move during cycling. Since the breechface was probably broached originally (and still is, many places), it's easy to set an angle there by shimming one end of the slide in the broach fixture. Link to comment Share on other sites More sharing options...
Flexmoney Posted July 10, 2006 Share Posted July 10, 2006 Admin note: I pulled one post from this thread. Talking about the breach face angle is fine, dandy and encourged.. Carrying on the the "discussion" from the other CLOSED thread is out of bounds. Link to comment Share on other sites More sharing options...
Radical Precision Designs Posted July 10, 2006 Share Posted July 10, 2006 Sorry Flex and y'all, my bad! I tried to hold back, but slipped!! About that little built-in quirk on the breech-face angle. You will notice the camming up to engage the lugs and create a delayed opening to eject/extract and feed: hence the moniker of "semi-auto delayed blowback" action. Somehow "ole Moses" decided to go above the horizontal line when his design reached the "ready to fire" condition. Since the slide and frame act parallel to each other, but the barrel is positioned at an angle, should the breechface had been at a square (90 degrees) angle the case would have sat with a gap at the top, and upon firing the rearward forces could/would deform the case possibly fostering some problems with extraction, etc. I know I wouldn't want to put any of "those" cases in my reloader as they would not be symetrical. Yet a slight variation can/could occur when some variations are introduced in modified versions of the 1911. For instance there is a noticeable difference in lug engagement angle between some of the "micro-sized 3 inches+ barrelled" 1911's and a 6" Long-Slide. And, I wonder if the manufacturer/fabricator took that into consideration when "altering" the slide dimensions from original specs. Also, the tendency of some builders to use "oversize/undersize" barrel links can increase/change the barrel angle some. (??) (Witness some of the off-center firing pin hits/indentations.) I haven't measured the angle of lock-up or breech-face in a Glock, but I wonder if that is one of the reasons why so many people have issues with cases fired originally in a Glock when reloading. (????) Link to comment Share on other sites More sharing options...
cking Posted July 10, 2006 Author Share Posted July 10, 2006 Travis I really enjoyed your discussions on the workings of old John Browning's design. So if you would lets hear about why breach face is angled. Also will I was looking over the prints I noticed vertical lugs match the angle of the breach. So when your fitting a hood/barrel and the barrel is in a linked down condition and the round has been picked up and stuffed into the chamber. What part of the barrel should make first contact with the slide? Should the hood make contact at the same time as the vertical surfaces? Tell us how you would fit a new barrel into a used but good condition modern slide. Thanks in Advance Link to comment Share on other sites More sharing options...
wsimpso1 Posted July 11, 2006 Share Posted July 11, 2006 cking, In my set of prints (Jerry Kuhnhausen's books), the breech face angle says (Ref) next to it. In my training, that means it is a reference dimension for setting something up, and is not intended to be a held dimension, with tolerances applied. Perhaps elsewhere the face is toleranced, and John Travis did indicate that a tolerance existed for this dimension. In any event, the angle is hooked up to the locking lugs forward of the ejection port, and I have to assume it is for establishing the locking lug dimensions with the barrel tilted slightly down at the muzzle. Why JMB and Colt wanted the muzzle down I am still noodling on. Does anybody have any real history to lay on us? Anyway, I think that I know why JMB and Colt did some other things related to this, but I have to look at my drawings before I go shooting off my mouth (my keyboard?) any further. Billski Link to comment Share on other sites More sharing options...
Guy Neill Posted July 11, 2006 Share Posted July 11, 2006 (edited) All guns have the bore pointing down, with respect to the sights. The amount of recoil while the bullet is still in the bore then sees the bullet exit at an upward angle, accounting for the trajectory we are used to. Easy to see if you place a dowel or yardstick or such on the open sights of a rifle, with another dowel in the bore. Or with a pistol/revolver. Guy Edited July 11, 2006 by Guy Neill Link to comment Share on other sites More sharing options...
wsimpso1 Posted July 13, 2006 Share Posted July 13, 2006 Looking at the prints reproduced for Jerry Kuhnhausen's books, it looks like the barrel is parallel to the slide when unlocked, and then the rear end of the barrel is lifted for engagement. The 89 deg 8 minutes means that there is about 52 minutes of tilt, or about 0.060" of lift 4" aft of the bushing. It all fits together... The big surprise is that I did some other looking around about all of this stuff on the locking and the barrel lugs not being able to move relative to the slide and the "Balanced Force Vector", did some calculations, and have some stuff to add, but it will take bit to type it all in, so maybe tomorrow... Billski Link to comment Share on other sites More sharing options...
John Travis Posted July 15, 2006 Share Posted July 15, 2006 (edited) Ya'll STILL ain't figgered it out? I'm plumb flabbergasted. All these Top Guns, and a simple question has'em all stumped... Radical P...Gap at the top if the breechface is dead vertical? Gimme a break! With a minute of angle being 1.047 inch at 100 yards, how small is that gap gonna be at a half-inch? (A 1/2-inch being roughly the height of the breechface.) The cartridge itself is nominally .476 with the chamber at .4795-.4835 inch. That's more than enough to allow for a tiny gap at the top. Helle's Belles...The cartridge rim ain't that square! Now that wsimp has noticed somethin' wrong with Kuhnhausen's "Balanced Thrust Vector" thing...you can go see more of his basic misunderstanding of the way the gun functions on Page 124, Volume 2. Top drawing, he clearly refers to the chamber face as the "Recoil Face"...which it's assuredly not. The recoil face is the breechface/breechblock. The barrel doesn't slam backward and drive the slide. If it did, the (real) breechface wouldn't last as long as a snowball in July. The slide recoils...not the barrel. Flex...No need to ban me. I don't think this is my kinda place anyway. Ya'll keep thinkin' about it. Maybe it'll come to ya... Edited July 15, 2006 by John Travis Link to comment Share on other sites More sharing options...
Merlin Orr Posted July 15, 2006 Share Posted July 15, 2006 (edited) Ya'll STILL ain't figgered it out? I'm plumb flabbergasted. All these Top Guns, and a simple question has'em all stumped...Radical P...Gap at the top if the breechface is dead vertical? Gimme a break! With a minute of angle being 1.047 inch at 100 yards, how small is that gap gonna be at a half-inch? (A 1/2-inch being roughly the height of the breechface.) The cartridge itself is nominally .476 with the chamber at .4795-.4835 inch. That's more than enough to allow for a tiny gap at the top. Helle's Belles...The cartridge rim ain't that square! Now that wsimp has noticed somethin' wrong with Kuhnhausen's "Balanced Thrust Vector" thing...you can go see more of his basic misunderstanding of the way the gun functions on Page 124, Volume 2. Top drawing, he clearly refers to the chamber face as the "Recoil Face"...which it's assuredly not. The recoil face is the breechface/breechblock. The barrel doesn't slam backward and drive the slide. If it did, the (real) breechface wouldn't last as long as a snowball in July. The slide recoils...not the barrel. Flex...No need to ban me. I don't think this is my kinda place anyway. Ya'll keep thinkin' about it. Maybe it'll come to ya... We finally agree on something... Edited July 15, 2006 by Merlin Orr Link to comment Share on other sites More sharing options...
XRe Posted July 15, 2006 Share Posted July 15, 2006 I haven't measured the angle of lock-up or breech-face in a Glock, but I wonder if that is one of the reasons why so many people have issues with cases fired originally in a Glock when reloading. (????) Not so much... the problems folks have (at least in .40) with Glock brass is that the back part of the case is basically unsupported (imagine a 1911 where you'd cut the ramp too far up into the chamber...). That causes the cases to "Guppy belly" - if you don't fully resize that case, it ends up bulged at the rear of the case and BAMMO - death jam. Flex...No need to ban me. I don't think this is my kinda place anyway. He wasn't talking about having removed a post of yours, John... What he's getting at is people making derogatory remarks about one another, etc, etc, etc.... Frankly - I think there was just some miscommunication on the other thread... not helped by everyone puffing up their chests and whatnot.... I learned a lot by reading both threads - at least, it got me thinking about the challenges of working on the design, etc. I'm looking forward to reading Bill's findings Dave Link to comment Share on other sites More sharing options...
John Travis Posted July 15, 2006 Share Posted July 15, 2006 Okay, Dave. I'll give it another try. wsimp...No need to make it more complicated than it is. The answer lies in Newton's Laws. High-School Physics. Equal and Opposite. Remember? Charge a muzzle loader and poke a bullet down the barrel. Cap it and pull the trigger. Boom! Kick! Recoil... Do it again and omit the bullet. kpow, and no kick. No bullet...No recoil. The bullet has to be there and it has to move. Once the bullet is gone, recoil is over, and any further rearward motion is purely on momentum. If the bullet exits BEFORE the slide moves, the slide WON'T move. Kuhnhausen has amended the BTV theory in recent books The initial link that I posted: "How the 1911 Really Works" was his early theory...and it was 101% wrong. But there's still the error on P 124, Volume 2. The chamber face is NOT a recoil face. The barrel doesn't recoil. The slide recoils. Otherwise, you'd have the reverse-image of the barrel hood tattooed on the breechface instead of the ghost of the cartridge rim. More complex version: Cartridge fires. Bullet slams into the rifling, and swages down under intense pressure and frictional resistance. Barrel is pushed forward. Same pressure is driving the slide rearward. (Remember that a vector of force acts equally in all directions. Up, down, sideways, diagonally, forward...and backward.) Locking lugs engage, and the breech is now locked. Slide's greater mass and more efficient conservation of momentum pulls the barrel rearward with it. Barrel reaches the disengagement point at nominally .100 inch of rearward travel...and begins to disengage and drop. The bullet must be gone before the barrel reaches the disengagement point...and the pressure at atmospheric or nearly so..or the barrel can't disengage. Try the door trick and it'll be clear. Now, about that angle... Link to comment Share on other sites More sharing options...
John Travis Posted July 15, 2006 Share Posted July 15, 2006 Nobody? Goodness gracious, Gertie! Bye now... Link to comment Share on other sites More sharing options...
XRe Posted July 16, 2006 Share Posted July 16, 2006 Okay, Dave. I'll give it another try. That part is clear to me It was the angle business..... Link to comment Share on other sites More sharing options...
Vlad Posted July 16, 2006 Share Posted July 16, 2006 I'm a fan of the 1911 but I think that if that breachface angle is that crucial to the firearm, then we all need to switch to glocks. What is the angle supposed to be again? And does anyone really think that the who knows how many Kimbers and Springfields out there actually meet that angle? Yet a lot of them seem to work quite well. I think any firearm with the following that the 1911 has is going to attract its own cult and some issues will start to pass from practical to religious. I'm not arguing if there is supposed to be an angle, or how much of one, or what it does. I'm just curious to know if anyone outside custom shops actually bothers to measure that angle on production line guns, and does it actually make a sufficiently large difference for anyone to care this much? At the end it is all about the shooting, and trigger puller doesn't do his or her job, the best hand crafted pistol in the world will not hit its target, it will jam, and it might even explode if the nut behind the bolt doesn't load his ammo right. I have a handgun or two which rattle if I shake them, where I'm willing to bet that the breach face angle is meaningless give the rest of the slop in the gun, and they work every time, for some definition of "every time" only meaningfull to competition shooters. One of them is even a 1911. As competition shooters know damn well, ALL guns fail sooner or later. Sometimes we know why, and sometimes we clear jams so fast that at the end of the run, we don't even remember what the jam looked like, never mind what its cause was. Practical shooters are some of the very few who actually wear out guns, and we are not taking about cheap guns either. A limited gun costs more then most custom 1911's and a full race open gun would cost more then any 1911 out there, unless they start making them out of stupid expensive materials or people start charging premiums based on name alone. These guns get shot until the frames crack, rails wear out, multiple barrels are worn away, locking lugs crack, slide stops break in half, and who knows what else goes wrong. Maybe there is a perfect angle for a breach face. Do practical shooters really care? Link to comment Share on other sites More sharing options...
Loves2Shoot Posted July 16, 2006 Share Posted July 16, 2006 (edited) Nobody? Goodness gracious, Gertie!Bye now... I'm no high fallutin' custom 1911 gunsmith, but it seems to me since the barrel tilts down a tiny bit, having the angle complimenting the downward tilt would make the face square in relation to the barrel would make for a more reliable design. But that just seems like common sense... I would like to hear the answer though from someone who seems to know a bit about the design of the 1911. Learning is a good thing in my book. ps. This practical shooter care, because I want the strongest, most reliable piece of hardware I can have. I've seen shoddy work from some "top" smiths and I've seen great work from no-namers. If I don't educate myself on what is good and what isn't that is MY fault. Edited July 16, 2006 by Loves2Shoot Link to comment Share on other sites More sharing options...
HSMITH Posted July 16, 2006 Share Posted July 16, 2006 There are a couple guys that need to take a pill, John isn't guessing here. John, go ahead and spill it. Link to comment Share on other sites More sharing options...
Vlad Posted July 16, 2006 Share Posted July 16, 2006 (edited) Seriously .. What is the angle supposed to be? Is 89'8" correct? I'm only asking because I'm trying to figure out how much of gap from the vertical that creates. Using 89'8", and quickly measuring the height of the breach face on my Springfield to be about 21mm, a get a difference from top to bottom of 0.3mm. That is on the small side of the medium sand, aproaching fine sand. So please someone tell me what the angle is supposed to be because if it really is 89'8", I have to ask .. Has anyone of you ever fire a round that you picked up from the ground? A round that might have had some sand on it? I sure have. Have you noticed any differnce? I haven't. Again, I'm not debating what perfection is here. It may very well be that perfection in a 1911 requires a specific angle. I'm just trying to figure out if it makes a practical difference. Edited July 16, 2006 by Vlad Link to comment Share on other sites More sharing options...
Radical Precision Designs Posted July 16, 2006 Share Posted July 16, 2006 (edited) It would help if we approched the dissecting of what seems to be a simple operation with the "inocense of a child", but (if we have it) with the wisdom of and experienced patriarch. Acting like a spoiled brat or rebelious youth, lashing at what he/she/they consider "the top" policy makers/rulers(?) is fruitless, even if a point is to be made. Early on I strived to take a simple approach to find how things worked, and tried (not always possible/attainable) to have all the influencing factors into consideration when formulating an opinion or expressing an understanding from my point of view. I like the "whole thing" approach, to look at the whole picture from above, and then zoom in for the details of individual interaction which makes the whole thing possible. The specific, minute details of interaction ARE important. It is also important to know (IF possible) the parameters restriction/constrictions established into the design prior to its taking form. This is paramount to the "original" designer to accomplish his/her task/project at hand. It is not as important to the subsequent "Monday morning quarterback" critic who had no bearing in the outcome of that design, but now decides to dissect it, even if benevolently. The 1911 design PLATFORM has been with us for a while now, and as soon as Colt lost any controlling powers over it the "hordes" descended upopn it. Who is to say what variations were introduced by these secondary manufacturers who had no need to abide by original blueprints? One thing I do consider is that the "moving force" behind J.M. Browning motivation was for eventual military contracts and production, most likely not under his control, but as under license and manufacturing necessary variations within the specifications allowed. In those days raw materials and manufacturing equipment was nothing like our modern availability and resources. When todays shooter rely on the proven history of a specific's 'smith/designer, it is not taken lightly, and like most lay person the emphasis is put on the actual performance rather than the minutiae of manufacturing. That is why most custom 'smiths spend so much time "checking out" various available components, not so much to compare them to the original drawings, but to check them out against the specific geometry of their project at hand for their intended use. There are ways around the design, to allow for changes. That is one of the "basic" parameters dictated by "military type" design requests. People with nothing better to do (or arm chair philosophers) can spend the whole day expounding upon next to nothing to accomplish nothing more than to irritate one another, and that's ok, if kept on that context, and still smile and go break bread or have a beer. If you study the thought on facilitating feeding, extracting, securing and easying initial-interim-ending lock up for delayed blow back functioning: it all falls into place. While different parts take their "cue" in the process line, their built in specifications and limitations will put in their contribution to the overal design. In simpler blunter terms: "preambles". That tiny bit of angle (based at a starting point to another contingent on barrel lenght) will "assist" in starting/guiding the cartridg/case into the extractor claw and seating it into the chamber, and reactively (start preamble) start the motion of extraction. However minimal its influence, it is irrelevant really, as most emphasis is been put in this thread as to what everybody's opinion is on it, or their twist of it. Have fun with it. Me, even though is Sunday, I've got work to do. Edited to say: Admin. If you find any portions of this post objectionable, please feel free to edit or delete as suited. Edited July 16, 2006 by Radical Precision Designs Link to comment Share on other sites More sharing options...
kruger Posted July 16, 2006 Share Posted July 16, 2006 Ya'll STILL ain't figgered it out? I'm plumb flabbergasted. All these Top Guns, and a simple question has'em all stumped... John, one of the nice things about this forum is the atmosphere here. Thanks to the moderators and regulars, this forum has very little in the ways of flamewars and disrespectful behaviour. Comments like those don't help. (Remember that a vector of force acts equally in all directions. Up, down, sideways, diagonally, forward...and backward.) I think you are confusing force vectors and pressure. Pressure acts in all directions equally, as described in Pascal's law. A vector is characterized by a direction and a magnitude. Multiple forces at a given point sum together (principal of superposition) using the parallelogram law, resulting in a single force acting in a single direction. http://en.wikipedia.org/wiki/Pressure_%28physics%29 http://en.wikipedia.org/wiki/Vector_%28spatial%29 Slide's greater mass and more efficient conservation of momentum pulls the barrel rearward with it. I'm sorry, but I don't understand how you are using the term "efficient conservation of momentum". Could you please explain your use of this term in greater detail? From a physics standpoint that combination of words makes as much sense as "north of the north pole". Additional context would help me understand what you are trying to say. Respectfully, Mark Kruger Link to comment Share on other sites More sharing options...
John Travis Posted July 16, 2006 Share Posted July 16, 2006 *sigh* I can't seem to distance myself, no matter how hard I try. Sorry for the snippet, Kruger. It was meant as a good-natured poke with a stick...and sorta givin' back what I got early on. All I was really tryin' to do...after the talk turned to advising the guy to take a file to the breechface...was try to save him a little grief. Okay. You're correct, of course. Pressure...acts in all directions equally. I was in a rush and still had Kunhausen's screwed-up theory on my mind. More Efficient Conservation...The slide is heavier than the bullet. It holds what it gained longer, and moves slower...I think the old shooters referred to this as "carries" further. Maybe the best way to...expound...is to compare .30 caliber bullets...both fired in the same .308 rifle. One is 165 grains at 2600 fps, and the other is 150 at 2800 fps. The light bullet kicks the heavy bullet's patoot for the first 100 yards. By 200, the 165 is closing the gap. At 300, they're almost neck and neck. by 400, the 165 inches past the 150, and at 450-500, the 165 is pullin' away like a drag car against a grocery getter. Flash back to the pistol. Bang! Bullet screamin' toward the muzzle while the slide goes "oof" and tries to get moving. Its greater mass slows it down, but it also picks up the barrel's mass as the lugs engage, and starts to pull it back with it. At .100 (nominally)inch of travel, the bullet exits, and has no more influence on the slide. The slide finishes the cycle under momentum alone. I'm usre there's a mathematical calculation that would describe this in more correct terms...but I'm not a mathematician or a physicist. I'm an armorer) So far, RPD has come the closest to answering the reason for the breechface angle. here's a "clew" for the guys here who are truly interested in figuring it all out...(Give a man a fish, etc.) The 1911 pistol is a recoil-operated, locked-breech design that operates on the basis of "Controlled...Feed." If the pistol loses positive control of the cartridge, even briefly...the chance of a malfunction greatly increases. Visualize the slide stripping a round from the magazine. As the round starts to slide up the breechface...just before extractor pickup...it begins its breakover to horizontal. What would occur...at that point...if the breechface were set at dead vertical? Then imagine what would occur if the angle was say...80 degrees. Think about it carefully...Therein lies the answer. Finally...though RPD may feel that it's insignifigant...consider that machining the breechface at 90 degrees would be faster, easier and cheaper on a production line, not even considering having to employ QA personnel to gauge the specs on X number of slides per day...with naturally a percentage of rejected parts. If that angle COULD have been eliminated, it WOULD have been eliminated...since the bottom line in any mass-production exercise is profit. The less precise it can be made, the cheaper it can be made...and the faster the contract or production quota can be met. The angle is critical. Link to comment Share on other sites More sharing options...
Loves2Shoot Posted July 16, 2006 Share Posted July 16, 2006 Thanks! Link to comment Share on other sites More sharing options...
Vlad Posted July 16, 2006 Share Posted July 16, 2006 I have a question ... If the breach face is at 90, all other things being equal, will the firearm function? Will any parts wear out sooner, and will that wear create a problem for the gun before other parts fail of natural wear? Link to comment Share on other sites More sharing options...
Radical Precision Designs Posted July 16, 2006 Share Posted July 16, 2006 John Travis- It is almost 6:30 PM here. Shortly I will quit work for the day. It is time for a beer. In case you'd want to know, I like Becks Dark beer on Sunday eves ... Link to comment Share on other sites More sharing options...
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