wsimpso1 Posted June 27, 2006 Share Posted June 27, 2006 My much modified and shot old Colt M1911 has the breach face of the slide looking terrible. Where the rear face of the barrel hood hits it, there is a clear indent with a slightly raised burr above and below. Just above the firing pin hole there is a crescent moon wear mark. Locking lugs in the barrel and slide look perfect, with no rounded ends or battering. It has rarely had trouble feeding lead bullets, and when it does, the case rim is stopped in the recess on the breach face. Jacketed bullets work fine, but I wonder for how much longer. A new Scheumann barrel and other parts are sitting ready, but I am wondering if the slide really justifies the fuss. It looks like it will take 0.005 to 0.015" worth of dressing to clean up the face. While the new barrel hood and underlug are oversized, I wonder if they can be made to fit correctly after that much material is removed and it also seems that the extractor will then be too far forward relative to the barrel and loaded round. Is this really an issue? If the slide really is better replaced, whose would you use? Or retire the whole pistol and build from new parts, properly fitted rails and barrel, etc. Comments, advice, and opinions are welcomed here. Billski Link to comment Share on other sites More sharing options...
Guy Neill Posted June 27, 2006 Share Posted June 27, 2006 (edited) If the gun is malfunctioning because of the breech face wear, then it needs to be fixed. If the barrel is otherwise fine (not shot out) I would contact a gunsmith about repairing the breech face and go from there. Guy Edited June 27, 2006 by Guy Neill Link to comment Share on other sites More sharing options...
reneet Posted June 27, 2006 Share Posted June 27, 2006 New firing pin bushing Link to comment Share on other sites More sharing options...
benny hill Posted June 27, 2006 Share Posted June 27, 2006 Take a small file & CAREFULLY take down the face untill the marks are gone & polish it, about .005 should do. Then install new barrel . Link to comment Share on other sites More sharing options...
wsimpso1 Posted June 27, 2006 Author Share Posted June 27, 2006 Thanks for the advice. The crescent moon wear mark is about the radius of the 45 ACP cases that it has fed so many thousands of and appears to be above where a firing pin bushing would go, but below where a chambered case sits, both locked and unlocked. I shall set about the task of measuring the face relative to something nearby, dress out the surface, and then measure again to determine how much had to come off. If that looks small enough (I HOPE that it is less than it looks like it is), then I will fit the new barrel. If it looks big, you folks will hear some more about this... Thanks again! Billski Link to comment Share on other sites More sharing options...
John Travis Posted July 6, 2006 Share Posted July 6, 2006 (edited) Hi guys. I might be able to offer some insight here. If the pistol is an old 1911...as in pre-A1...it's one that didn't have the hardened steel recoil insert in the breechface. The problem of peening around the firing pin port was discovered by Colt in 1935. The insert was authorized and adopted in 1936 beginning with serial number 710001. All WW2 contract slides and spares, and commercial models were fitted with the inserts, and continued until post-war production, when the slides were hardened throughout, beginning sometime in late 1946 or early 1947. Many damaged slides were retro-fitted with the inserts, but the slides were still dead soft, except the WW2 contract pistols which were spot hardened in key areas. Your slide can be repaired, but it's still soft, and firing should be limited. Simply dressing the damage to true up the face will affect headspace. Edited July 6, 2006 by John Travis Link to comment Share on other sites More sharing options...
benny hill Posted July 7, 2006 Share Posted July 7, 2006 It will not affect headspace on a newly fitted barrel as he intends to fit up. Link to comment Share on other sites More sharing options...
wsimpso1 Posted July 7, 2006 Author Share Posted July 7, 2006 I was not aware that early M1911's had soft slides. My pistol is a Series 70, made by Colt in 1979, so it is hard. Using a metal straightedge, the wear is really pretty small, only a few thousandths, so I will dress it out and fit the new barrel, then finish the chamber and set headspace with my chamber reamer. I recognize that doing so results in the extraction groove sitting deeper relative to the extractor. Considering that many .45's actually headspace on the extractor, this one will have a better chance of actually headspacing on the case rim, but apparently that is just not a problem. Thanks again for your thoughts! Billski Link to comment Share on other sites More sharing options...
John Travis Posted July 7, 2006 Share Posted July 7, 2006 (edited) Howdy wsimpso, Excessive headspace comes in two flavors. Headspacing on the extractor is not only incorrect, but also rare. It occurs mainly when the chamber is cut far too deep...but isn't a danger. The problem that results from excessive headspace in that direction is usually erratic ignition and/or misfires. An increase in headspace that results from removing material from the breechface causes the headspace to increase in the dangerous direction. That is...the case moves backward under pressure until it hits the slide and stops. As it backs out of the chamber, it loses head support. Rear headspace occurs due to barrel lug setback and/or wear or an out of spec condition between the breechface and the front of the barrel lugs relative to the rear faces of the slide lugs. In these condtions, the breech essentially opens a bit when the gun is fired and the slide is driven rearward, while the pressure and friction between bullet and barrel holds the barrel forward. Barrel and slide are driven in opposite directions until the lugs engage. Finally...that your pistol is a Series 70 is no guarantee that it's correctly hardened. The fix for your pistol is to machine out the damaged area and install a hardened steel insert. George Smith over at EGW can handle that for ya in fine fashion. Luck! Benny Hill wrote: >It will not affect headspace on a newly fitted barrel as he intends to fit up.< Yes it will. Anything that changes the dimension from the breechface to the rear faces of the slide lugs affects headspace, although, hard-fitting a barrel will take care of most of the negatives involved. Edited July 7, 2006 by John Travis Link to comment Share on other sites More sharing options...
John Travis Posted July 7, 2006 Share Posted July 7, 2006 Whenever I hear "Old Colt" this is what comes to mind. Circa 1919 and mechanically perfect, right down to the bore. In the background is a minty 1945 production Remington Rand. Now, let's see if this photobucket will post here. Mods...If I'm outta line, please delete the post with my belssings and apologies. Link to comment Share on other sites More sharing options...
EricW Posted July 7, 2006 Share Posted July 7, 2006 Benny, Are you taking notes...? Link to comment Share on other sites More sharing options...
Merlin Orr Posted July 7, 2006 Share Posted July 7, 2006 Benny,Are you taking notes...? Now, Now....... Link to comment Share on other sites More sharing options...
tightloop Posted July 7, 2006 Share Posted July 7, 2006 Eric That was tacky... Link to comment Share on other sites More sharing options...
EricW Posted July 7, 2006 Share Posted July 7, 2006 Hey! I'm just trying to make sure Benny gets his full value from his forum membership. I'm only here to help. Link to comment Share on other sites More sharing options...
Larry White Posted July 7, 2006 Share Posted July 7, 2006 Benny has an inquireing mind. I'm sure he would want to know.------Larry Link to comment Share on other sites More sharing options...
John Travis Posted July 8, 2006 Share Posted July 8, 2006 Aw, now...Don't give him a hard time. You'd be surprised at the experienced people who don't fully understand how the thing works...even a few gunsmiths. Jerry Kuhnhausen, for instance...used to think that recoil and slide movement rearward occurs after the bullet leaves the muzzle. Early printings described this as "Breaking the Balanced Thrust Vector." He has since eliminated it in more recent publications. Apparently, someone sat him down and explained it to him. To wit: If the bullet exits BEFORE the slide moves, the slide WON'T move. The balanced thrust vector exists...It just doesn't occur at the time and place that he described. Also...The term "Locks up like a vault" to describe the fit is incorrect and misleading. When the gun is static and in battery, it's not locked. It's held in battery by recoil spring tension and...if tightly fitted...friction. Wedged into battery, for lack of a better term...but it's not locked. The locked breech part comes when the gun is fired. Interesting, what? Link to comment Share on other sites More sharing options...
Merlin Orr Posted July 8, 2006 Share Posted July 8, 2006 Wow, John. Very interesting stuff for sure. I take it you are a gunsmith yourself....? Link to comment Share on other sites More sharing options...
John Travis Posted July 8, 2006 Share Posted July 8, 2006 Wow, John. Very interesting stuff for sure. I take it you are a gunsmith yourself....? Well...more of a mechanic. Armorer is the official term, I guess, but it all started in 1964. Link to comment Share on other sites More sharing options...
Merlin Orr Posted July 8, 2006 Share Posted July 8, 2006 Wow, John. Very interesting stuff for sure. I take it you are a gunsmith yourself....? Well...more of a mechanic. Armorer is the official term, I guess, but it all started in 1964. Interesting way of putting it.... Work for a agency, individual or what, if I might ask? Link to comment Share on other sites More sharing options...
John Travis Posted July 8, 2006 Share Posted July 8, 2006 Nope. Retired. Now I just tweak a pistol now and then for friends and such. Don't do custom work in the strict sense and mainly focus on makin' a problem child behave. Oh...While we're on the subject of misleading terms: "The link unlocks the barrel from the slide." Lock occurs when the gun is fired and contines until the bullet exits. At that point, the gun is unlocked. All the link does is get the barrel down and out of the slide's way. The link doesn't...actually can't...unlock the barrel from the slide while the bullet is in transit due to the vector that has the locking lugs engaged while barrel and slide are being slammed in opposite directions. If the link actually pulls the barrel down while it's under firing pressure, the link will either break within a few rounds, or it will stretch until the rear of the lower barrel lug hits the impact surface in the frame while the lugs are still part-way in the slide...and the locking lugs will crack, or shear within a few rounds. To illustrate: Stand in front of a door that opens toward you. Have a 12-year-old kid stand on the other side and push against the door hard...and try to turn the knob. Unless you have stong hands, you probably won't be able to move it without damaging the inner workings of the knob...if you can move it at all. The striker is the barrel lug. The striker plate is the slide lug. The knob is the barrel link. While the door is under force, the striker and striker plate are "locked", and they won't unlock until the kid lets off. (Don't tell your kids about this.) Link to comment Share on other sites More sharing options...
Merlin Orr Posted July 8, 2006 Share Posted July 8, 2006 Actually I guess I am just being nosey.... I should have/meant to ask if you were or had ever been a professional armorer or gunsmith, who you worked for and for how long. But, like I said, just being nosey trying to figure out what your qualifications are and how much credence to give your statements... When you mention how you told/clued in someone who is in the Hall of Fame like Jerry Kuhnhausen or make statements that point out your superior knowledge to a outstanding gunsmith such as Benny Hill it just surprises me that I have never heard of you or seen one of your guns in the field.... Forgive me, please Link to comment Share on other sites More sharing options...
benny hill Posted July 8, 2006 Share Posted July 8, 2006 John, you can remove material from the breach face & it won't affect headspaceing on a new barrel. You will cut the hood to a snug fit & then ream the chamber to a nice .005 headspace & presto a great fitted barrel. You then can make adjustments to the bottom lug or frame if needed for the proper quartant of the barrel. ALL good smiths do it this way. Link to comment Share on other sites More sharing options...
John Travis Posted July 8, 2006 Share Posted July 8, 2006 Benny, quite correct as long as you use a barrel with a semi-finished chamber, but not all gunsmith fit barrels have semi-finished chambers. Schuemann may be the only supplier unless you special order and ask for it. Merlin...The reason that you haven't seen my guns in the field is because I haven't really fielded any that would draw recognition. Like i said...most of my practive has been reliability tuning and rebuilding/restoring worn-out USGI and commercial pistols. They look pretty much like they did when I started. For the record, many knowledgeable people have wondered what Kuhnhausen was thinking when he published his Balanced Thrust Vector theory. He clearly stated that: "Once the bullet has cleared the muzzle, the balanced thrust vector is broken, freeing the slide to move rearward." Maybe not verbatim...but that pretty well sums it up...and it's incorrect. In order for recoil to occur...which is essentially what the slide does...the bullet has to be present. If there's no bullet, there's no recoil. No recoil, no slide movement. It would be like firing a blank. >If the bullet exits before the slide moves, the slide WON'T move.< I'll go find a link so that you can read it for yourself. Stand by... Link to comment Share on other sites More sharing options...
benny hill Posted July 8, 2006 Share Posted July 8, 2006 John, myself & all the smiths I know will not use a finished barrel as we have no control of the finished product. Any one useing a finished barrel is not a smith but a assembler of parts. Link to comment Share on other sites More sharing options...
John Travis Posted July 8, 2006 Share Posted July 8, 2006 (edited) Here's the exerpt from the text by Kuhnnhausen: How the 1911 Really Works" Courtesy of The American Rifleman. Will return to add the link so you can see the whole thing. ***************** Firing Phase B: Horizontal disengagement At the end of the firing phase, the bullet exits the muzzle and drops gas pressure inside the barrel. Bullet departure breaks the balanced thrust vector established when the bullet was in the barrel as in fig. 4A. In terms of the effect on the pistol, this action enables the top locking lugs to horizontally disengage (see National Match barrel note in next phase) and imparts a rearward force on the slide assembly equal to the inertia of the departing bullet. Then, because the slide assembly has a greater relative rest mass -plus the added benefit of the recoil spring- inertial energy is absorbed as the slide recoils to the rear. ***************** Benny...Don't mean to be argumentative, but once most of the gunsmith-fit barrels are fitted up, the chamber and headspace dimensions are generally within .003 inch of minimum specs. About the only finish reaming necessary is in straightening out any taper present, or cleaning up the leade...which doesn't entail deepening the chamber. In fact, most of the ones that I've done for equal lug engagement leave the chamber about .903-905 inch. And...he ain't gonna get the breechface true with a file anyway. Stand by for the link... Here's the link. Scroll down to the second one from the bottom. http://www.m1911.org/technic_forum.htm Edited July 8, 2006 by John Travis Link to comment Share on other sites More sharing options...
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