1911 unsupported case

logeorge · August 22, 2021, 06:39 PM

I've had a copy of the Kuhnhausen manual on the 1911 for several years now, but haven't seriously read it until this week, as I haven't had a 1911 in an even longer time. In the part about head space and throating the chamber, he claims that excess head space will increase the amount of the case that is unsupported, and has to be added to the distance from the breech face to the top of the ramp. As I understand it, the barrel and slide are locked together at the moment of firing, the breech face is part of the slide and the case head is in contact with the breech face because of the pressure of the expanding gasses inside the case. In that situation, the amount of unsupported case is equal to the distance from the breech face to the top of the ramp inside the barrel. So, how can extra head space have any effect on the unsupported area of the case? Am I missing something, or is Kuhnhausen wrong? I hate to argue with a recognized authority on the subject, but I don't see how this can be. What you think?? L. O. G.

**Aguila Blanca** · August 22, 2021, 08:54 PM

In a 1911, the cartridge is supposed to be located when in battery (i.e. "headspaced") by the case mouth stopping against the shoulder at the forward end of the chamber. If the barrel is properly machined, this in turn limits how much of the case web is exposed in that bottom part of the chamber mouth that forms the entry into the chamber.

That's the barrel.

Now the barrel has to be fitted to the slide so that when the barrel is locked up in battery, there isn't an excessive gap between the case head and the breechface. If there IS an excessive gap, then upon firing the case can move backward in the chamber before being stopped by the breechface, thereby exposing too much of the case web at the chamber ramp.

ChasHam · August 23, 2021, 08:08 AM

Many years ago, I decided to polish the feed ramp of my trusty Series 70 Colt 1911.

Long story short--I got a little too aggressive with the Dremel's felt buffing wheel and while rounds fed smooth as silk, fired cases bulged down near the base.

Hello 1-800-Colt-- send me a new barrel :-(

Jim Watson · August 23, 2021, 08:36 AM

A local gunsmith said of guns like that, "not just throated, it had its tonsils removed."

logeorge · August 23, 2021, 09:17 AM

I understand how the head space is measured. but can't visualize how excess clearance at the front can effect the amount of unsupported case at the rear. Once the case is against the breech face, the unsupported area can't change, as I see it. I could be missing something. I'm certainly no expert on 1911s. L. O. G.

**Aguila Blanca** · August 23, 2021, 10:00 AM

Quote:

Originally Posted by logeorge

I understand how the head space is measured. but can't visualize how excess clearance at the front can effect the amount of unsupported case at the rear. Once the case is against the breech face, the unsupported area can't change, as I see it. I could be missing something. I'm certainly no expert on 1911s. L. O. G.

You are assuming that the case head is against the breech face AND that the case mouth is against the chamber shoulder, so the base of the case is mostly supported by the chamber. In a properly fitted 1911 this is the case (no pun intended).

But ... consider the possibility that the barrel is not properly fitted to the slide. We say that a .45 ACP headspaces on the case mouth, but the headspace is measured from the chamber shoulder (which is part of the barrel) to the breechface (which is part of the slide). Clearly, then, if the barrel is fitted to lock up a bit farther forward in the slide, the distance from the chamber shoulder to the breechface will increase. If the case head is in contact with the breechface when fired (or if the case moves back to make contact before the case has fully expanded), more of the case will be hanging out of the chamber and exposed to excessive expansion (or blowout).

logeorge · August 23, 2021, 12:23 PM

I must not have made myself clear in the post. I am not assuming that the case is in contact with the head spacing shoulder in the chamber. Quite the opposite. What I'm saying is that if the case is against the breech face at the moment of firing and the barrel and slide are locked together, then the amount of unsupported case is determined by the distance from the breech face to the front of the ramp in the barrel. The case can move no further to the rear and the space in front of the case will have no effect on how much of the case is not supported. If the case were to move forward out of contact with the breech face and could stay there in spite of the internal pressure, then the unsupported area would be reduced, not increased. If my assumptions are wrong, please explain. I'm just trying to get a handle on this. L. O. G.

**Aguila Blanca** · August 23, 2021, 01:52 PM

Quote:

Originally Posted by logeorge

What I'm saying is that if the case is against the breech face at the moment of firing and the barrel and slide are locked together, then the amount of unsupported case is determined by the distance from the breech face to the front of the ramp in the barrel. The case can move no further to the rear and the space in front of the case will have no effect on how much of the case is not supported.

But you are assuming that the barrel is correctly fitted to the slide. It can't happen but imagine what things would look like if the barrel were fitted such that the chamber is 1/4 of an inch too far forward in the slide when it's locked up. The barrel and chamber are all the correct dimensions, but the barrel sits 1/4 inch too far forward in the slide when in battery. Now put a cartridge in the chamber. If the case head is in contact with the breechface, there's an extra quarter of an inch of case wall hanging out of the chamber, unsupported.

Got it?

Now reduce that quarter inch to 0.10" or 0.05". A barrel being "fitted" to a slide .10" out of spec is unlikely. .05" might be possible. After all, the fit of the barrel to the slide is already subject to tolerances. It only takes a couple of thousandths beyond the worst-case in-spec dimension to be a problem.

HiBC · August 23, 2021, 03:43 PM

Given the "diversity" of 1911 components floating around,the 110 years of service,and the you tube diy kitchen table armorers...

I would not assume anything regarding 1911 dimensional conformance.

I have both volumes of Kuhnhausen. There are dimension drawings in the books. There are Datums,or landmarks that allow checking "pretty close" enough to determine any major discrepancy. Your calipers ought to be able to check about anything to .002. Generally, with a 1911 if your calipers can tell you the locking lug or underlug seem within .005 of Kunhausen's drawings ....its in the ballpark. Odds are,there is some noise in the measurement
(Hot tip,I use an adjustable parallel to measure breech face to rear face of the rear slide locking lug. Good number to have.)

Your question seems to be about headspace /head clearance in the context of unsupported chamber goose eggs/case failures. Am I right?

Do we pretty much agree at the timing of the pressure curve where case bulging would take place (near peak) the case head is firmly against the breech?(Regardless of headspace/head clearance)

Even extreme out of spec chamber depth would still fully support the case at the case mouth.

The "goose egg" area of non support is generally in the feed ramp area roughly 5 oclock to 7 oclock.
There is most of the chamber that is cylindrical geometry. Where it is cylindrical,the cartridge case is supported.

From the factory,there is a chamfer or bevel at the chamber mouth to facilitate feeding. There is a corner,or chine, at the transition of that chamfer,or throat,to the cylindrical geometry of the chamber.

As the barrel is made,that clean,distinct corner defines where full chamber support ends. Its got nothing to do with headspace.
The well meaning diy 1911 "mechanic" does not understand the 1911,but he has an unlicensed Dremel tool. He does not really like that clean,crisp line.
He's gonna make SHINY,cuz thats gooder. And he's going to "Smooth and blend" Thats where he ruins the barrel. That rounding,smoothing,blending is removing critical chamber support. That edge was where it belongs.

And misguided "polishing the feed ramp" is a good way to ruin the frame.

The headspace might be perfect with the throat and feed ramp ruined.

logeorge · August 23, 2021, 05:47 PM

That's what I'm saying. The "goose egg" will be the same whether the head space shoulder is too far forward or not. Extra space at the front of the case won't make the "goose egg" longer, the distance from the breech face to the "chine" is what determines how much of the case is unsupported at firing or in other words, how long the "goose egg" is. I'm not trying to get an argument started, I'm just trying to find out if I have the right take on the situation. I'm aware that over polishing the ramp in the barrel is a good way to ruin the barrel. L. O. G.

HiBC · August 23, 2021, 07:31 PM

Seems like we are on the same page.

Make a cutaway case.Then you can see how the design of the case head works with the chine location.

Headspace is no less important

**Aguila Blanca** · August 23, 2021, 09:36 PM

Quote:

Originally Posted by LOGEORGE

That's what I'm saying. The "goose egg" will be the same whether the head space shoulder is too far forward or not. Extra space at the front of the case won't make the "goose egg" longer, the distance from the breech face to the "chine" is what determines how much of the case is unsupported at firing or in other words, how long the "goose egg" is.

The part I highlighted is correct. What you are overlooking is that the "chine" (as you call it) is part of the barrel. If the barrel and chamber are machined within specified dimensions and tolerances, the distance from the shoulder of the chamber to the "chine" is a given.

If a barrel with an in-spec chamber is fitted to the slide incorrectly, with the barrel too far forward, then there is extra space between the "chine" and the breechface.

Of course, if an in-spec barrel is fitted correctly and then someone starts carving away at the chamber throat ramp, that's another way to create more unsupported case -- but that doesn't affect headspace.

HiBC · August 24, 2021, 06:02 AM

I think we have succeeded in communicating the ideas.
Of course,proper headspacing is an important factor in the function of a firearm.
I recall finding a William Blake line...Maybe in "Proverbs from Hell" that goes something like "All attempts at foolproofing are folly,for the genius of the fool is infinite"
The fool's infinite genius . Often paired with Murphy's law.
We could delve into the hog wallow of "Kitchen table Dilrod takes his SNARKOPARTS 1911 kit of unknown global discards (Like Momma Gumps Box of Chocolates) and proceeds to precision fit the barrel and slide lugs with the modern do-it-all tool,the 4 inch disc grinder. And a cape chisel he stole from Grandpa. Beat upon with the broken claw framing hammer."

I do not want to suggest its inconceivable Dilrod find a way to induce enough of a headspace issue to contribute to unsupported case head bulging .
Dilrod knows no bounds.

A separate issue is achieving case bulges by removing the supporting steel from the chamber itself,headspace unaffected, But Dilrod and his Dremel find a way.

Then there is the old reliable "Major Caliber or Bust " route...as Dilrod adds plus signs to his "P" s . +++p+++!! Bring on the Blue Dot!!

Not talking about headspace gauge ,thousandth or two precision headspace here, but battling,rattling 1911 headspace...
Drop-in GI surplus barrel headspace,isn't case bulging headspace.

Now,45 GAP ammo in a 45 ACP,or 45 ACP in a 460 Rowland, 9x19 in a 9x23,etc are "wrong ammo" situations that create significant head clearance
It does not necessarily follow that the cartridge case will be less supported at the case head,

Aguila's point that breech face to supporting chamber (chine) distance matters is correct

I think its likely that Glock holds very close production tolerances. I have a hunch the 40 S+W Glock pistols known for bulged cases were probably headspaced perfectly.

logeorge · August 24, 2021, 08:01 AM

What I'm saying is that if the barrel and slide are correctly fitted, then the amount of unsupported case is established by the distance from the breech face to the most forward point of the ramp in the barrel. A chamber that is cut too deeply will have no effect on the amount of unsupported case. Kuhnhausen says that it will. Maybe I misunderstood him. I'll go back an reread it. L. O. G.

**Unclenick** · August 24, 2021, 09:42 AM

I looked at Kuhnhausen on pages 55 and 56 where he is discussing this. You are correct that he states the problem in an unclear fashion. I am guessing that his way of putting it comes from "old school" gun work. When I first learned to build match 1911s we still used the old-school method of TIG welding a build-up of magazine spring steel (the late Bob Day's material of choice) onto the barrel extension (hood) and link lugs of a standard barrel for fitting the two. In that scenario, the built-up barrel extension adds to the headspace by forcing the barrel further forward than would occur with a shorter extension, and that increases the unsupported gap as well. So it isn't actually the headspace so much as how you arrived at it that counts.

For target-level softball loads, some extra unsupported space does not cause a dangerous degree of case bulging. In a hardball gun shooting full pressure ammo, though, headspace increased by adding to the barrel extension may, in some guns, cause vulnerability to case blowout, especially with cheap or thin brass. The numerous aftermarket match barrels that require fitting attempt to compensate for barrel extension fitting when they cut the chamber, but the best way to control headspace is to get a barrel made with a short chamber so you can finish ream after fitting the barrel extension to the particular gun in question. If you want a fully supported case, then you are going to have to cut the frame for an integral feed ramp barrel.

74A95 · August 24, 2021, 10:21 AM

Quote:

Originally Posted by logeorge

What I'm saying is that if the barrel and slide are correctly fitted, then the amount of unsupported case is established by the distance from the breech face to the most forward point of the ramp in the barrel. A chamber that is cut too deeply will have no effect on the amount of unsupported case.

You're thinking is correct.

Sarge · August 24, 2021, 10:53 AM

Quote:

Originally Posted by Jim Watson

A local gunsmith said of guns like that, "not just throated, it had its tonsils removed."

LMAO

logeorge · August 24, 2021, 11:58 AM

Unclenick &74A95: Thank you! I was beginning to think that I'm loosing my cognitive abilities due to my advanced age. By the way, Unclenick, I'm originally form Lima, Ohio, for what that's worth. L. O. G.

RickB · August 25, 2021, 10:38 AM

I did a little experiment with some of my guns, cutting a strip of newsprint to use as a shim, to see how many thicknesses would fit between the breechface and barrel hood, while still allowing lock-up.

Guns with fitted barrels allow only a couple of thicknesses, while one would allow the slide to move rearward very noticeably, 8-10 thicknesses of paper, which would allow that much additional headspace compared to the static chambered position of the cartridge at firing.

Any deepening of the barrel throat - moving it forward - would increase the amount of exposed brass, but that wouldn't change the headspace.

HiBC · August 25, 2021, 12:37 PM

Without arguing with anyone, I certainly have closely controlled the barrel hood to breech fit building 1911s.

But lets think about it. Isn't the fit that matters between the barrel locking lugs and the slide regarding headspace?

Do we want a tight fit with the hood to breech holding the locking lugs off contact?

Or do we want working clearance between the hood and breech allowing full contact between the slide and barrel locking lugs?

Asking for a friend.

logeorge · August 26, 2021, 01:40 PM

So, it seems that in fitting a barrel one would to need to have some slight clearance between the breech face and the end of the barrel hood to ensure the locking lugs on the barrel are not unseated from contact with the locking recesses in the slide. Seems fairly obvious, if you think about it, but something that could be overlooked by an inexperienced person. By the way, I'm not working on a 1911, just trying to clarify a point. Thanks to all who replied to my post. L. O. G.

logeorge · September 7, 2021, 04:23 PM

Thinking about this thread, I realized I had made an erroneous statement in my last post. Too long a barrel hood won't unseat the locking lugs , but will prevent them from engaging in the first place. It seems to me that there has to be a slight clearance between the back end of the barrel and the ledges in the slide, as well as the breech face and the end of the hood to allow the slide and barrel to lock together. It would need to be minimal, though, in order to prevent the locking surfaces from slamming together and peening the locking surfaces.

August 22, 2021, 06:39 PM	#1
logeorge Member Join Date: December 24, 2007 Location: Ardmore, AL Posts: 68	1911 unsupported case I've had a copy of the Kuhnhausen manual on the 1911 for several years now, but haven't seriously read it until this week, as I haven't had a 1911 in an even longer time. In the part about head space and throating the chamber, he claims that excess head space will increase the amount of the case that is unsupported, and has to be added to the distance from the breech face to the top of the ramp. As I understand it, the barrel and slide are locked together at the moment of firing, the breech face is part of the slide and the case head is in contact with the breech face because of the pressure of the expanding gasses inside the case. In that situation, the amount of unsupported case is equal to the distance from the breech face to the top of the ramp inside the barrel. So, how can extra head space have any effect on the unsupported area of the case? Am I missing something, or is Kuhnhausen wrong? I hate to argue with a recognized authority on the subject, but I don't see how this can be. What you think?? L. O. G.

August 22, 2021, 08:54 PM	#2
Aguila Blanca Staff Join Date: September 25, 2008 Location: CONUS Posts: 18,460	In a 1911, the cartridge is supposed to be located when in battery (i.e. "headspaced") by the case mouth stopping against the shoulder at the forward end of the chamber. If the barrel is properly machined, this in turn limits how much of the case web is exposed in that bottom part of the chamber mouth that forms the entry into the chamber. That's the barrel. Now the barrel has to be fitted to the slide so that when the barrel is locked up in battery, there isn't an excessive gap between the case head and the breechface. If there IS an excessive gap, then upon firing the case can move backward in the chamber before being stopped by the breechface, thereby exposing too much of the case web at the chamber ramp. __________________ NRA Life Member / Certified Instructor NRA Chief RSO / CMP RSO 1911 Certified Armorer Jeepaholic

August 23, 2021, 12:23 PM	#7
logeorge Member Join Date: December 24, 2007 Location: Ardmore, AL Posts: 68	1911 unsupported case I must not have made myself clear in the post. I am not assuming that the case is in contact with the head spacing shoulder in the chamber. Quite the opposite. What I'm saying is that if the case is against the breech face at the moment of firing and the barrel and slide are locked together, then the amount of unsupported case is determined by the distance from the breech face to the front of the ramp in the barrel. The case can move no further to the rear and the space in front of the case will have no effect on how much of the case is not supported. If the case were to move forward out of contact with the breech face and could stay there in spite of the internal pressure, then the unsupported area would be reduced, not increased. If my assumptions are wrong, please explain. I'm just trying to get a handle on this. L. O. G.

August 23, 2021, 03:43 PM	#9
HiBC Senior Member Join Date: November 13, 2006 Posts: 8,283	Given the "diversity" of 1911 components floating around,the 110 years of service,and the you tube diy kitchen table armorers... I would not assume anything regarding 1911 dimensional conformance. I have both volumes of Kuhnhausen. There are dimension drawings in the books. There are Datums,or landmarks that allow checking "pretty close" enough to determine any major discrepancy. Your calipers ought to be able to check about anything to .002. Generally, with a 1911 if your calipers can tell you the locking lug or underlug seem within .005 of Kunhausen's drawings ....its in the ballpark. Odds are,there is some noise in the measurement (Hot tip,I use an adjustable parallel to measure breech face to rear face of the rear slide locking lug. Good number to have.) Your question seems to be about headspace /head clearance in the context of unsupported chamber goose eggs/case failures. Am I right? Do we pretty much agree at the timing of the pressure curve where case bulging would take place (near peak) the case head is firmly against the breech?(Regardless of headspace/head clearance) Even extreme out of spec chamber depth would still fully support the case at the case mouth. The "goose egg" area of non support is generally in the feed ramp area roughly 5 oclock to 7 oclock. There is most of the chamber that is cylindrical geometry. Where it is cylindrical,the cartridge case is supported. From the factory,there is a chamfer or bevel at the chamber mouth to facilitate feeding. There is a corner,or chine, at the transition of that chamfer,or throat,to the cylindrical geometry of the chamber. As the barrel is made,that clean,distinct corner defines where full chamber support ends. Its got nothing to do with headspace. The well meaning diy 1911 "mechanic" does not understand the 1911,but he has an unlicensed Dremel tool. He does not really like that clean,crisp line. He's gonna make SHINY,cuz thats gooder. And he's going to "Smooth and blend" Thats where he ruins the barrel. That rounding,smoothing,blending is removing critical chamber support. That edge was where it belongs. And misguided "polishing the feed ramp" is a good way to ruin the frame. The headspace might be perfect with the throat and feed ramp ruined. Last edited by HiBC; August 24, 2021 at 04:04 AM.

August 23, 2021, 05:47 PM	#10
logeorge Member Join Date: December 24, 2007 Location: Ardmore, AL Posts: 68	1911 unsupported case That's what I'm saying. The "goose egg" will be the same whether the head space shoulder is too far forward or not. Extra space at the front of the case won't make the "goose egg" longer, the distance from the breech face to the "chine" is what determines how much of the case is unsupported at firing or in other words, how long the "goose egg" is. I'm not trying to get an argument started, I'm just trying to find out if I have the right take on the situation. I'm aware that over polishing the ramp in the barrel is a good way to ruin the barrel. L. O. G.

August 23, 2021, 08:08 AM	#3
ChasHam Senior Member Join Date: August 27, 2018 Location: Deep South Posts: 130	Many years ago, I decided to polish the feed ramp of my trusty Series 70 Colt 1911. Long story short--I got a little too aggressive with the Dremel's felt buffing wheel and while rounds fed smooth as silk, fired cases bulged down near the base. Hello 1-800-Colt-- send me a new barrel :-(

August 23, 2021, 08:36 AM	#4
Jim Watson Senior Member Join Date: October 25, 2001 Location: Alabama Posts: 18,539	A local gunsmith said of guns like that, "not just throated, it had its tonsils removed."

August 23, 2021, 09:17 AM	#5
logeorge Member Join Date: December 24, 2007 Location: Ardmore, AL Posts: 68	I understand how the head space is measured. but can't visualize how excess clearance at the front can effect the amount of unsupported case at the rear. Once the case is against the breech face, the unsupported area can't change, as I see it. I could be missing something. I'm certainly no expert on 1911s. L. O. G.

August 23, 2021, 07:31 PM	#11
HiBC Senior Member Join Date: November 13, 2006 Posts: 8,283	Seems like we are on the same page. Make a cutaway case.Then you can see how the design of the case head works with the chine location. Headspace is no less important Last edited by HiBC; August 23, 2021 at 07:36 PM.

August 24, 2021, 06:02 AM	#13
HiBC Senior Member Join Date: November 13, 2006 Posts: 8,283	I think we have succeeded in communicating the ideas. Of course,proper headspacing is an important factor in the function of a firearm. I recall finding a William Blake line...Maybe in "Proverbs from Hell" that goes something like "All attempts at foolproofing are folly,for the genius of the fool is infinite" The fool's infinite genius . Often paired with Murphy's law. We could delve into the hog wallow of "Kitchen table Dilrod takes his SNARKOPARTS 1911 kit of unknown global discards (Like Momma Gumps Box of Chocolates) and proceeds to precision fit the barrel and slide lugs with the modern do-it-all tool,the 4 inch disc grinder. And a cape chisel he stole from Grandpa. Beat upon with the broken claw framing hammer." I do not want to suggest its inconceivable Dilrod find a way to induce enough of a headspace issue to contribute to unsupported case head bulging . Dilrod knows no bounds. A separate issue is achieving case bulges by removing the supporting steel from the chamber itself,headspace unaffected, But Dilrod and his Dremel find a way. Then there is the old reliable "Major Caliber or Bust " route...as Dilrod adds plus signs to his "P" s . +++p+++!! Bring on the Blue Dot!! Not talking about headspace gauge ,thousandth or two precision headspace here, but battling,rattling 1911 headspace... Drop-in GI surplus barrel headspace,isn't case bulging headspace. Now,45 GAP ammo in a 45 ACP,or 45 ACP in a 460 Rowland, 9x19 in a 9x23,etc are "wrong ammo" situations that create significant head clearance It does not necessarily follow that the cartridge case will be less supported at the case head, Aguila's point that breech face to supporting chamber (chine) distance matters is correct I think its likely that Glock holds very close production tolerances. I have a hunch the 40 S+W Glock pistols known for bulged cases were probably headspaced perfectly.

August 24, 2021, 08:01 AM	#14
logeorge Member Join Date: December 24, 2007 Location: Ardmore, AL Posts: 68	1911 unsupported case What I'm saying is that if the barrel and slide are correctly fitted, then the amount of unsupported case is established by the distance from the breech face to the most forward point of the ramp in the barrel. A chamber that is cut too deeply will have no effect on the amount of unsupported case. Kuhnhausen says that it will. Maybe I misunderstood him. I'll go back an reread it. L. O. G.

August 24, 2021, 09:42 AM	#15
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,061	I looked at Kuhnhausen on pages 55 and 56 where he is discussing this. You are correct that he states the problem in an unclear fashion. I am guessing that his way of putting it comes from "old school" gun work. When I first learned to build match 1911s we still used the old-school method of TIG welding a build-up of magazine spring steel (the late Bob Day's material of choice) onto the barrel extension (hood) and link lugs of a standard barrel for fitting the two. In that scenario, the built-up barrel extension adds to the headspace by forcing the barrel further forward than would occur with a shorter extension, and that increases the unsupported gap as well. So it isn't actually the headspace so much as how you arrived at it that counts. For target-level softball loads, some extra unsupported space does not cause a dangerous degree of case bulging. In a hardball gun shooting full pressure ammo, though, headspace increased by adding to the barrel extension may, in some guns, cause vulnerability to case blowout, especially with cheap or thin brass. The numerous aftermarket match barrels that require fitting attempt to compensate for barrel extension fitting when they cut the chamber, but the best way to control headspace is to get a barrel made with a short chamber so you can finish ream after fitting the barrel extension to the particular gun in question. If you want a fully supported case, then you are going to have to cut the frame for an integral feed ramp barrel. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

August 24, 2021, 11:58 AM	#18
logeorge Member Join Date: December 24, 2007 Location: Ardmore, AL Posts: 68	Unclenick &74A95: Thank you! I was beginning to think that I'm loosing my cognitive abilities due to my advanced age. By the way, Unclenick, I'm originally form Lima, Ohio, for what that's worth. L. O. G.

August 25, 2021, 10:38 AM	#19
RickB Senior Member Join Date: March 1, 2000 Location: Boise, ID Posts: 8,518	I did a little experiment with some of my guns, cutting a strip of newsprint to use as a shim, to see how many thicknesses would fit between the breechface and barrel hood, while still allowing lock-up. Guns with fitted barrels allow only a couple of thicknesses, while one would allow the slide to move rearward very noticeably, 8-10 thicknesses of paper, which would allow that much additional headspace compared to the static chambered position of the cartridge at firing. Any deepening of the barrel throat - moving it forward - would increase the amount of exposed brass, but that wouldn't change the headspace. __________________ Runs off at the mouth about anything 1911 related on this site and half the time is flat out wrong.

August 25, 2021, 12:37 PM	#20
HiBC Senior Member Join Date: November 13, 2006 Posts: 8,283	Without arguing with anyone, I certainly have closely controlled the barrel hood to breech fit building 1911s. But lets think about it. Isn't the fit that matters between the barrel locking lugs and the slide regarding headspace? Do we want a tight fit with the hood to breech holding the locking lugs off contact? Or do we want working clearance between the hood and breech allowing full contact between the slide and barrel locking lugs? Asking for a friend.

August 26, 2021, 01:40 PM	#21
logeorge Member Join Date: December 24, 2007 Location: Ardmore, AL Posts: 68	So, it seems that in fitting a barrel one would to need to have some slight clearance between the breech face and the end of the barrel hood to ensure the locking lugs on the barrel are not unseated from contact with the locking recesses in the slide. Seems fairly obvious, if you think about it, but something that could be overlooked by an inexperienced person. By the way, I'm not working on a 1911, just trying to clarify a point. Thanks to all who replied to my post. L. O. G. Last edited by logeorge; August 26, 2021 at 01:48 PM.

September 7, 2021, 04:23 PM	#22
logeorge Member Join Date: December 24, 2007 Location: Ardmore, AL Posts: 68	Thinking about this thread, I realized I had made an erroneous statement in my last post. Too long a barrel hood won't unseat the locking lugs , but will prevent them from engaging in the first place. It seems to me that there has to be a slight clearance between the back end of the barrel and the ledges in the slide, as well as the breech face and the end of the hood to allow the slide and barrel to lock together. It would need to be minimal, though, in order to prevent the locking surfaces from slamming together and peening the locking surfaces.