Hey Tuner, xray of 1911 firing

Status
Not open for further replies.
Lets see if I've got this down yet.

The force (high pressure gases), contained from going sideways by the chamber, pushes the bullet forward and the breechblock rearward. The bullet moving forward tries to drag (friction) the barrel with it. The rearward movement of the slide and the forward movement of the barrel keep the barrel lugs locked against the slides grooves (lugs?) with the front of the barrel lugs engaged with the rear of the slides grooves. When the bullet has exited the barrel there is no more forward force (drag) acting upon the barrel so the force holding the lugs locked is lessened greatly and it is now easy for the link to pull it down out of engagement.

Any comments, corrections ?

Don't worry, let er rip, I left my feelings in the truck. Enlighten me. :uhoh:
 
Last edited:
At the point shown in the radiograph, you'd see the barrel lugs forward against the slide lugs regardless, since the slide and barrel have already started their recoil cycle, and the slide is coming back. I don't think the "forward force"/friction of the bullet in the barrel is anywhere NEAR as strong as has been suggested previously, otherwise you'd feel a significant decrease in recoil if you shot the exact same load in a revolver as in a semi-auto (provided the total weights of the guns are the same). The only real factors that matter in this equation are the weight and velocity of the bullet on one side, versus the weight and velocity of the recoiling parts of the pistol on the other.
 
Any comments, corrections ?
Click to expand...

Walkalong...You've got it!

I don't think the "forward force"/friction of the bullet in the barrel is anywhere NEAR as strong as has been suggested previously,
Click to expand...

SDC...If you'd ever seen locking lugs with stair-step deformations...barrel and slide...you'd understand how high the forces are....but you're correct in that
in this picture...the forces have dropped considerably.

The front/rear forces are at their highest at the time of peak chamber pressure...which occurs at about the first half-inch of bullet movement.
This is where the majority of the recoil impulse occurs...and the majority of the bullet's final velocity, too. Beyond that point...any recoil impulse that comes is almost insignifigant by comparison.

Think of it like this: (Simplified)

A 5-inch barrel has 4.1 inches of rifling. If the muzzle velocity is 850 fps...and assuming that the 35 fps per inch...gained or lost...rule of thumb is accurate...then 4X35=140...how does the remaining 710 fps occur?

Recalculate it, using one-half inch for the peak...leaving 3.6 inches to accelerate the bullet to the final velocity. Then 3.6X35=126 fps...which means that the first half-inch of barrel will produce 724 fps.

It woild also be useful to understand the method which was once used to equalize the locking lugs...that is...get all of them bearing against their opposing lug faces in the horizontal plane. They were fitted to leave the thrid lug...the forwardmost lug...kissing about .002 inch of air, and fired with proof-level ammunition 2-3 times in order to deform the first and second lugs, and bring the third one into engagement.

Even with the softer barrel steels of the day...that takes a lot of force in just 3 rounds.
 
"I don't think the "forward force"/friction of the bullet in the barrel is anywhere NEAR as strong as has been suggested previously..."

Try and push a bullet through by hand.
 
I've pounded through a few squibs, but if that "pulling friction" WAS as strong as some seem to believe, then why isn't it apparent in a firearm that doesn't work in the same way as a semi-auto? If it actually contributed in any sort of way to the lock-up of a 1911, then you should be able to feel a definite difference in the recoil between a 1911 and a revolver of the same weight, no?
As for the "stair-step" deformations, that sounds just as likely to be a result of improper lock-up in the first place, with ignition occuring when there's less than full lock-up of the lugs.
 
But you're claiming that "(The first half-inch of bullet travel) is where the majority of the recoil impulse occurs...", ie. BEFORE the bullet even LEAVES the pistol. How can you even claim that this is possible? Unless the bullet leaves the pistol, you have no recoil to operate the pistol (and a squib demonstrates exactly that). I've seen a fair number of revolvers that have suffered flame cutting and topstrap erosion, but this is a different mechanism at work; if a 1911 is set up with anywhere NEAR proper tolerances, those recoil forces would also have to crush part of the barrel hood in order to crush the lugs on the barrel. If you ever have a junker frame, slide, and barrel to play with, I invite you to try an experiment I once saw with a Hi-Power; grind the locking lugs completely off the barrel, reassemble it, and see how the pistol functions as a straight blowback (in a rest, please). It's definitely hard on the pistol (which is why you want to do it with some scrap parts), but it still functions.
 
BEFORE the bullet even LEAVES the pistol. How can you even claim that this is possible? Unless the bullet leaves the pistol, you have no recoil to operate the pistol (and a squib
Click to expand...

Wow! I don't know how to start...or where...but I'll give it a shot so you can understand this.

If you understand anything about Newtonian physics, you'll know that the recoil...essentially the reaction side of the action/reaction equation...begins at the exact same instant that bullet movement starts, and the gun is in recoil well before the bullet exits the muzzle.

Just in case you got this idea from reading and believing Kunhausen's "Balanced Thrust Vector" sheep dip...it can't happen. If the gun doesn't recoil before the bullet exits...it won't recoil.


Read that again and let it sink in...and believe it.

If the bullet is gone BEFORE the gun kicks...the gun WON'T kick. That's why hollywood pretend autoloading guns require blank firing devices in order to cycle.

What little recoil effect produced by the residual pressures after burning 5 or 6 grains of pistol powder probably wouldn't knock a fly off your hand.

In order for the ballistic event to produce recoil, the bullet has to be in the barrel, and it has to move. If the bullet is missing, half of the action/reaction pair isn't present. If there's no action, there can be no reaction.

if a 1911 is set up with anywhere NEAR proper tolerances, those recoil forces would also have to crush part of the barrel hood in order to crush the lugs on the barrel.
Click to expand...

If you understood how the pistol functions, you would see that the slide is moving away from the barrel hood...so there can be no crushing.
The hood isn't a forth lug.

If you ever have a junker frame, slide, and barrel to play with, I invite you to try an experiment...
Click to expand...

IF?? After over 43 years of wrenchin' on 1911 pistols, I've probably got more junk slides and barrels out in the shop than you've ever seen...and I've experimented with it in ways that would give John Browning a case of the hives.

Go study it a while longer and report back. ;)
 
A "consequence" of the recoil occurring before the bullet leaves the barrel probably accounts for the different POI people have shooting the same gun/same ammo...I'd bet!

How you grip, strong/weak, one/two handed, etc.
 
"If you understand anything about Newtonian physics, you'll know that the recoil...essentially the reaction side of the action/reaction equation...begins at the exact same instant that bullet movement starts, and the gun is in recoil well before the bullet exits the muzzle."

No, only PART of the pistol is in recoil; the slide and barrel (locked together) on one side of the equation, with the bullet (travelling much faster, because it's so much lighter) on the other. It's not until the force of the slide and barrel is transferred to the frame (by which time the bullet is LONG down-range) that the shooter even FEELS any recoil. It's simply the mass of the slide and barrel together that balance that equation out against the mass of the bullet (the first slow, the second fast), and it's what delays the opening of the breech until after pressures have dropped.

"If you understood how the pistol functions, you would see that the slide is moving away from the barrel hood...so there can be no crushing.
The hood isn't a forth lug."

Can you explain to me how "the slide is moving away from the barrel hood" when the slide and barrel (chamber, hood, lugs, and all) are LOCKED TOGETHER by the same lugs that you claim are being "crushed"? It isn't until after the link pulls the barrel down out of alignment with those lugs that the barrel has (or should, if it has proper tolerances) any motion independent of the slide.
 
Good Morning. I am going to jump in here with a little

example that might help put this in perspective. If you

watch a wave on the beach long enough you will

understand what everyone is trying to say. The wave

starts by rolling up the beach which is the momemtum and

as the wave reaches the top of its cycle it will reach a

relaxed state or conservative momentum and as the wave

rolls back down the beach it will gain speed because of

the resistence to the beach or being of less resistence.

When the wave hits another wave as it comes in, What

happens? , The wave hits more resistence and slows down,

thus causing another moment of conservative momemtum

which then releases that momemtum against the incoming

wave. As this happens both waves push away from each

other in opposite directions, that is recoil.
 
A "consequence" of the recoil occurring before the bullet leaves the barrel probably accounts for the different POI people have shooting the same gun/same ammo...I'd bet!
Click to expand...

Yessir. You've got it!

SDC...
Can you explain to me how "the slide is moving away from the barrel hood" when the slide and barrel (chamber, hood, lugs, and all) are LOCKED TOGETHER by
Click to expand...

I'll try...

The ballistic event is nothing more than a miniature explosion between the base of the bullet and the breechblock...transferred, of course, through the case rim.

The bullet...being an uber-tight fit in the barrel...yanks the barrel hard forward when it hits the rifling. At the same instant, the opposing force noted in Newton's 3rd...action/reaction forces always travel in pairs...is slamming the slide in the opposite direction...trying to shear the locking lugs and separate the slide and barrel. If the lugs weren't present, the barrel and slide would be separated...just like a straight blowback...but because they're locked together BY the lugs...they move as a unit. The barrel is actually part of the slide for a brief period, as it is pushed rearward. The slide pulls the barrel backward with it...as a unit...until it reaches the linkdown point...roughly .100 inch in an ordnance-spec pistol. At some fraction of an inch BEFORE the linkdown point is reached...the bullet exits. Pressure drops...and the breech can safely open. The barrel drops, and the slide continues rearward on the momentum that it aquired during that first .100 inch of travel...when it was being driven by the forces contained therein.

Got it?

Once more...

The forces acting on the barrel and slide are literally trying to rip the lugs off the barrel, and separate the two parts. Go look at a cutaway drawing...look closely at the lugs and how they relate...open your mind...and study it. It'll jump off the page atcha.

Cheers!



Lock your hands in front of your chest and pull in opposite directions.

Barrel lug deformation is always on the front face. Slide lug deformation is always on the rear face.

Study Newton-1 and 3...Look at the barrel and slide lugs...and it'll come to ya.
 
"If the lugs weren't present, the barrel and slide would be separated...just like a straight blowback...but because they're locked together BY the lugs...they move as a unit."

And this is what I was trying to demonstrate with my earlier "grind the lugs off of a barrel and try it" example; I've seen it work with a Hi-Power, and don't see any reason why it wouldn't work exactly the same with a 1911. If you tried it and it functions (as it does with a Hi-Power), it would convince you that this "bullet pulling the barrel forward as a part of the locking mechanism" is a figment of your imagination. The slide alone has so much more mass than a bullet that it's IMPOSSIBLE for the slide to open before the bullet has left the barrel.
As for the barrel/slide lug deformation, this is EXACTLY what you'd expect to see as soft or loose-tolerance parts wear, since it is those surfaces that grind against each other during the locking/unlocking process, correct?
 
Tuner,

If I understand all this, a bullet should actually accelerate the instant it clears the barrel due to drop in friction with the barrel. Then after some relatively short distance start to slow down due to air friction and lack of propulsion. on the side of recoil, I've heard that when the A-10 Warthogs fire their 30mm Gatlings, that the recoil slows then down a noticeable amount. Good thread; interesting and thought provoking. Thanks to all.
 
I may well be very wrong on this but I don't think the bullet can speed up after leaving the barrel simply because there is nothing pushing it anymore. The pressure has dropped to almost nothing by the time the bullet gets out of the barrel.

SDC, why do you think the barrel and slide actually lock together? Simply because its a neat thing for them to do?
I have never measured it but I am sure that it takes more pressure to push the bullet out the barrel than it does to push the slide back. So I would think under the right circumstances that the slide COULD open before the bullet left the barrel if the lugs were not present.

Again I may be wrong on all fronts.
 
"SDC, why do you think the barrel and slide actually lock together?"
Because that's what they were designed to do by Browning; however, DESIGNING something to work in a certain way doesn't mean that that something actually WORKS that way; as exhibit one, I give you the Blish "lock" in the 21/28 Thompson. As I've told Tuner, there's an easy way to check this out, and I've seen it done with the Browning Hi-Power; simply take the lugs off a barrel (turning the pistol into a straight blowback), and fire it that way. As long as the bullet can travel down the 5" of barrel in a shorter time than the much heavier slide and barrel can recoil over a distance of approx. 1/2", then the system will work, locked breech or not.
 
Because that's what they were designed to do by Browning; however, DESIGNING something to work in a certain way doesn't mean that that something actually WORKS that way
Click to expand...

I was not around when Mr. Browning was doing his thing but I would think his design works exactly the way he wants it to.

When firing a centerfire round in a blowback design as you describe, what kind of flash/blow out do you have out the ejection port?
 
Yeah, the Browning without locking lugs and the Hi-Point will
fire standard 9mm Parabellum as straight blowback.
Just don't ask me to fire 9mm with an "M38" headstamp or
any other +P+ or submachinegun 9mm ammo in a blowback
only handgun. Cluck-a-cluck-a, I is chicken.
The locking lugs may only be a safety feature, but safety is
a nice feature to have, given the variety of ammo out there.
 
"When firing a centerfire round in a blowback design as you describe, what kind of flash/blow out do you have out the ejection port?"

I saw it done with C1 (Sterling) smg ammo, and it produced a fairly bright muzzle flash and some "slightly pregnant"-looking brass, but nothing really out of the ordinary at the breech end.
 
If you tried it and it functions (as it does with a Hi-Power), it would convince you that this "bullet pulling the barrel forward as a part of the locking mechanism" is a figment of your imagination.
Click to expand...

*sigh*

If you would simply take the time to look at the X-Ray photograph, you could see the figment of my imagination at work...and if you doubt that a bullet that is being swaged into a barrel with lands that are .006 inch smaller than its diameter doesn't hold that barrel forward...then you just haven't thought about it hard enough.

If those opposing forces will stretch the topstrap of a modern revolver, they'll surely deform those relatively small radial lugs in the 1911 pistol. I'd suggest that you try one that Brickeyee suggested. Push a bullet through a barrel from chamber to muzzle if you doubt that it happens.

You are correct on one point though...kinda.

The slide alone has so much more mass than a bullet that it's IMPOSSIBLE for the slide to open before the bullet has left the barrel.
Click to expand...

The link can't draw the barrel out of engagement with the slide because of the slide's mass? No. It can't do it because...before the bullet exits...the lugs are horizontally engaged under pressure. Barrel being held forward and slide being shoved backward. That's what achieves the locked part of the locked breech. Before the gun fires, it's not actually locked. It's just held in battery by the force of the recoil spring, and...in a tightly fitted gun...a sort of wedging action. But locked up ? No.

I know that you think you understand this thing...and you seem to be pretty close...but you're still short on a few points. The part about recoil not starting until the bullet exits was the biggest clue. As we say here in the south: "That dog won't hunt."

And...If there's anything that I've learned over the course of my life...it's that, once a man's mind is locked onto an idea or a woman...no matter how bad or how wrong...there just ain't much way to shake him loose from either one of'em.

I'd suggest that you go and study on it long and hard. I'll give you my E-mail address if you'd like, so that if you have any questions, you can write to me without having to resurrect what is likely to be a dead thread.

Luck!

PcMakr...No. The bullet cant' accelerate after it exits. There is no force acting on it other than its momentum...which gravity and friction are fighting.

presspuller...He's correct. The barrel and slide are locked together by the lugs...and pressure.

Blowback designs delay the breech opening...the separation of barrel and breechblock...by slide/bolt mass and/or spring strength. The locked breech/recoil operated weapon functions under the exact same mechanics...but uses a different mechanism to delay the breech opening. Namely...by tying the barrel and slide together, the barrels mass is added to the slide's. In the case of the 1911...that equals about 40% the slide's mass. The LB/RO design is much more forgiving of spring strength.
 
"*sigh*

If you would simply take the time to look at the X-Ray photograph, you could see the figment of my imagination at work...and if you doubt that a bullet that is being swaged into a barrel with lands that are .006 inch smaller than its diameter doesn't hold that barrel forward...then you just haven't thought about it hard enough."

Looking at that radiograph, I don't see the BARREL pulling the SLIDE FORWARD, I see the SLIDE pulling the BARREL REARWARD (and the position of the slide on the frame supports that); if these "barrel pulling forward" forces are as strong as you say they are, what happens to them when an identical cartridge is fired in a firearm that doesn't HAVE a slide or barrel to recoil? They can't magically disappear, so they have to be so small as to be immeasurable when we're firing those guns.

"The link can't draw the barrel out of engagement with the slide because of the slide's mass?"
No, the link doesn't have anything to do with it, because it doesn't come into play until after the bullet has already exited the barrel. If you imagine a straight blowback, while the bullet is travelling down the bore, you essentially have a bullet on one side of an explosion in a tube, and the slide on the other side of that explosion. Because the slide is so much heaver (at least 30 times, in the case of a 1911 GM), it only travels a short distance before the bullet exits that tube, and the pressure drops to ambient (and this would happen regardless of any locking or delaying mechanism to affect that slide).

"The part about recoil not starting until the bullet exits was the biggest clue."
I probably should have explained what I mean by this; until the slide (with the barrel locked to it) starts to transfer its motion to the frame, from the shooter's perspective, there ISN'T any recoil. He's just holding a frame, and the little one-stroke internal combustion engine that's riding on the rails of that frame doesn't even begin to affect him until a long time (comparatively speaking) after the bullet has already left the barrel.
 
Yadda Yadda

Lord...Gimme strength. Brickey! I may turn this over to you. I'm wearin' out.

I understand that the link doesn't come into play until the bullet exits...unless the gun is badly out of time. We covered that. The link starts to draw the barrel down at the linkdown point...at .100 inch of rearward barrel travel...Remember?

Look...Here's your chance to prove me utterly and completely wrong.

Go get an unfired bullet. 185..200...230 grain. It doesn't matter. Take the barrel out of your pistol...drop the bullet into the chamber...and use a dowel rod to push the bulllet through the barrel and out the muzzle. Be sure and grip the barrel in your hand. No fair using a bench vise. If your theory is correct, it should be a piece of cake...even if you only use your thumb and finger to hold the barrel.

Come back and tell us what you learned.
 
He's just holding a frame, and the little one-stroke internal combustion engine that's riding on the rails of that frame doesn't even begin to affect him until a long time (comparatively speaking) after the bullet has already left the barrel.
Click to expand...

I think we can disregard that statement as utterly and completely wrong...but as noted...you really don't have a clue how this thing works.

If you imagine a straight blowback, while the bullet is travelling down the bore, you essentially have a bullet on one side of an explosion in a tube, and the slide on the other side of that explosion. Because the slide is so much heaver (at least 30 times, in the case of a 1911 GM), it only travels a short distance before the bullet exits that tube, and the pressure drops to ambient (and this would happen
Click to expand...

Almost. When the barrel is added to the slide, the mass is about 40 times greater.

Brickeyeeee!!!! Your turn! I gotta go deal with these dogs.
 
Look...Here's your chance to prove me utterly and completely wrong.

Go get an unfired bullet. 185..200...230 grain. It doesn't matter. Take the barrel out of your pistol...drop the bullet into the chamber...and use a dowel rod to push the bulllet through the barrel and out the muzzle. Be sure and grip the barrel in your hand. No fair using a bench vise. If your theory is correct, it should be a piece of cake...even if you only use your thumb and finger to hold the barrel.
Click to expand...

The trouble is, this experiment doesn't tell you ANYTHING about how the force it takes to drive a bullet down a barrel is supposed to affect the cycling of a 1911; while the bullet is in the bore, that barrel may as well be a tube that is permanently WELDED CLOSED at one end. Can you tell me what happens to these "barrel pulling forward" forces when fired in a revolver? If they amounted to anything, why wouldn't we see them to an even GREATER extent in something like a bolt-action rifle?
 
Quote:"He's just holding a frame, and the little one-stroke internal combustion engine that's riding on the rails of that frame doesn't even begin to affect him until a long time (comparatively speaking) after the bullet has already left the barrel."

I think we can disregard that statement as utterly and completely wrong...but as noted...you really don't have a clue how this thing works.
Click to expand...

How so? The force of the slide recoiling isn't transferred to the frame (and from there, to the shooter) until AFTER the slide compresses the recoil spring and or/reaches the end of its travel, all of which happens "a long time (comparatively speaking) after the bullet has already left the barrel."

I seem to recall once hearing something along the lines of: "once a man's mind is locked onto an idea or a woman...no matter how bad or how wrong...there just ain't much way to shake him loose from either one of'em."
:D
 
Status
Not open for further replies.

Similar threads

M
  • Locked
Hey 1911tuner heres the update on my 1911
Replies
3
Views
515
Phoenix_III
P
P
  • Locked
1911 clone in .380 shoots high and jams
Replies
5
Views
393
patentnonsense
P
K
  • Locked
Met 1911 Tuner
2 3 4
Replies
97
Views
4K
carpettbaggerr
C
T
  • Locked
low firingpin hit
Replies
8
Views
619
tac5mh8
T
M
  • Locked
Tuner: 1911 GI Safety Question
Replies
3
Views
651
Mossyrock
M
Back
Top