Roles of Springs in Recoil and Feeding of the 1911 Government

[Josh Smith]

Hello,

I wrote the below for a member of another board. It became longer and more in-depth than I'd originally intended and I'm posting it on several boards because I realized it might help others when it comes to gunsmithing their 1911 pistols. When I searched for a similar online reference, I couldn't find one so I wrote one.

I'm not a 1911 expert. There are true 1911 artisans out there, and I don't belong to that society. Some do consider me an expert in the Mosin-Nagant, but I do not. I only study and report findings. A gun is a gun, but each has their own nuances which must be learned through intensive study, and a bolt action rifle is not a 1911. When I say "a gun is a gun" I only mean that they have the same basic parts, which may be extremely different.

They have bolts or slides which feed the rounds and keep them chambered for firing.

They all have hammers and firing pins (even if these are combined into single-piece units called "strikers".)

They all have sears, and all have disconnectors after a fashion, even if the "disconnector" is a manual separation of the sear and hammer mating surfaces.

All have springs, which are used to store energy for operation. In a manual pistol or bolt action rifle, this may only be the mainspring which drives the hammer. In a semi-auto, you may have three or more springs which all work together.

Discounting the sear spring for now, in the 1911 pre-series 80, there are three basic springs which work in relationship during firing:

1. The mainspring, which drives the hammer and retards the slide;

2. The recoil return spring, which does act against recoil but is really made to return the slide after recoil;

and

3. The firing pin spring, which returns the firing pin after ignition and prevents inertial firing.

Let us for a moment consider only the mainspring. Imagine a 1911 with no return spring nor firing pin spring. Imagine a round chambered and full magazine loaded into this hypothetical pistol.

When you squeeze the trigger, these events happen:

1. The hammer drops, striking the firing pin.

2. The round discharges.

3. The slide and barrel assembly recoil as one piece, against the hammer.

- This is important. This is the mainspring's role in managing recoil. The time the mainspring, through the hammer, can keep the barrel and slide locked together is called dwell time. Generally speaking, the more dwell time, the better. Early unlocking can cause a host of problems, from firing pin wipe to blowback of gasses during early unlocking.

- Hypothetically, on a Government, the hammer and mainspring should provide all the control needed to retard unlocking of the slide/barrel assembly. This is theoretical and I wouldn't try it.

- The original 1911 had a square-bottom firing pin stop. Because the military carried their pistols in Condition 3, and because some folks found it difficult to rack the slide with the hammer down in Condition 3 to ready their pistols, the 1911a1 was introduced as having a radiused FPS as one of its features. This allowed easier racking of the slide with the hammer down, but also hurt the dwell time. This wasn't important in a mass-produced fighting pistol, but most civilians ask more from their weapons and those who know change the stock radiused FPS to a square-bottom pre-a1 stop for better dwell time.

- Take away from this that the primary recoil and barrel/slide lockup timing control is the mainspring, NOT the "recoil" (slide return) spring.

Now, let's take up where we left off: The 1911 has recoiled against the force of the mainspring. The slide and barrel have successfully separated and now the slide is setting open after the extractor and ejector have worked their magic to discard the fired case.

There is another round just begging to be fed if something would only move the slide forward to do it!

Enter the recoil return spring.

1. Upon ignition, the recoil spring begins compressing, storing energy released from the round.

- The greater the amount of energy stored, the more force the recoil return spring will exert against the force of recoil. This means that the heavier the recoil return spring, the greater the feel of the recoil imparted to your hand.

2. At full slide rearward travel, resistance meets inertia, and the slide pauses momentarily.

- This is extremely important. If the slide doesn't pause long enough, it can actually overrun the next round up in the magazine! This is also why weak magazine springs cause malfunctions. Shorter 1911 pattern pistols like the Officer's have less inertia in their slides, which make them more dependent upon springs for the same power ammo, and make them more sensitive to changes in their working environments and tolerances than the 5" version of the same model.

3. After the pause, resistance overcomes inertia. The energy stored in the recoil return spring moves the slide forward, stripping the next round from the magazine and loading it into the pistol's chamber.

All's well, right? Well, no. Remember inertia? Your firing pin is an inertial firing pin, meaning it cannot touch the round's primer and the hammer at the same time.

So, now that we have forward inertia, the inertial firing pin slams into the round's primer as soon as the slide and barrel lock and slam suddenly to a stop. Buuuuuuuurrrrrrrrrrrrrp! A firing pin in motion tends to stay in motion, and all that. The feds frown on runaway guns as fully auto.

Therefore, the firing pin must have a spring to arrest its forward inertia, as well. In addition, a strong firing pin spring keeps firing pin wipe from happening: The firing pin must not be in contact with the primer when the spent round is ejected.

So, upon firing a 1911, one squeeze of the trigger does this:

1. The hammer drops, hitting the firing pin.

2. The firing pin slams forward under inertia. Some of this energy is stored in the firing pin return spring to return the firing pin to rest after the job is done, so that the above listed problems don't manifest.

3. The round ignites, and recoil begins moving the slide and barrel assembly backwards. The recoil return spring begins storing energy from the ignited round.

4. The barrel and slide move backward together about 1/4", providing enough energy to overcome the inertia of the hammer and start it moving backward.

5. The barrel and slide unlock after a safe dwell time and the round is ejected.

6. The slide continues rearward, fully cocking the hammer.

7. The slide pauses momentarily at full rearward travel.

8. The slide begins forward under the stored power of the recoil return spring. Before the slide can get up much forward velocity, it is slowed again as it strips the next round from the magazine. This is very important.

9. Due to the engineered slowing of the slide, it comes forward to a soft stop.

- This is why it's OK to chamber a round from a magazine, but not to drop the slide on an empty chamber! A slide dropped on an empty chamber is not slowed and will batter the lugs and cause the sear to bounce. It strains the gun.

10. The pistol is now ready to fire again.

Hopefully you now understand why a radical departure from stock weight springs is not a good idea, generally speaking. Yes, some do this, but generally for gaming, where they're firing reduced loads and have matched the springs to those loads.

The reduction of the mainspring reduces the amount of dwell time. The mainspring is very important to recoil management in the pistol. Reducing its weight reduces the ability of the pistol to handle full-power loads.

Increasing the recoil return spring's weight allows the slide to slam forward faster and harder than designed. If you're using weak magazine springs, you may have problems feeding, though this isn't an issue on Government-sized pistols as much as it is on shorter, smaller models. If they ever start using aluminum slides, it will be a problem on Government-sized 1911s.

An increased recoil return spring will also make the slide return faster, potentially battering the lugs and possibly causing sear bounce, which damages the sear nose and could potentially fire the pistol if said pistol has iffy engagement of the hammer hooks to the sear nose, including but not limited to short hammer hooks or negative sear engagement.

Hopefully this has helped someone.

Regards,

Josh

[jaytothekizzay]

Nice read... thank you

Sent from my SM-G935V using Tapatalk

[redlightrich]

Thank you for a great read. I am curious, where does this information originate from? Did you read it, or have you been studying the 1911 for a while?

Thanks again

Rich

[Josh Smith]

Hello,

I've been at it for a while now. I had a little formal training and years of in-depth study for personal gratification. The Mosin lets me eat and the 1911 helps me relax when I'm done with the Mosin work for the day.

I've been kicking around the idea of transitioning into custom 1911 builds, but that depends on the political climate. Already, it's much more expensive to start than even 20 years ago.

Josh

[JohnKSa]

7. The slide pauses momentarily at full rearward travel.

Usually it bounces. You can actually get a little more slide forward velocity when firing the gun (due to the bounce) than you can when racking it.

The time the mainspring, through the hammer, can keep the barrel and slide locked together is called dwell time.
...
Hypothetically, on a Government, the hammer and mainspring should provide all the control needed to retard unlocking of the slide/barrel assembly.

What provides locking timing on pistols without hammers?

[Aguila Blanca]

Originally Posted by Josh Smith

3. The firing pin spring, which returns the firing pin after ignition and prevents inertial firing.

The 1911 firing pin is an inertial firing pin. The firing pin spring does not prevent inertial firing. That's how a 1911 fires.

[RKG]

Any discussion of springs in a Gov't Model should include a fourth: the so-called "sear" spring (it actually acts upon multiple parts). I have encountered a number of pistols having problems because the sear spring wasn't installed correctly after a detail strip, or because it had lost its proper shape.

[Josh Smith]

Aguila,

Inertial firing from forward momentum imparted by the slide.

I thought that was clear from the context. Wasn't it?

Josh

[Josh Smith]

RKG,

I generally agree.

Because this is "Roles of Springs in the Recoil and Feeding of the 1911 Government," I felt like the lockwork could be left for another time, including only the hammer since it helps control recoil.

Josh

[Josh Smith]

John,

I assume, depending on design, that the recoil spring and lockup geometry provide the lockup timing.

I'd also assume that the striker cocks during slide close, which would help cushion the gun's locking lugs but also provide for a weaker ignition strike, compared to hammer guns.

This is drawn from schematics. I don't own a striker fired pistol.

Josh

[Jim Watson]

Not to be a nitpicker but since you are making authoritative statements, they ought to be right.

The firing pin stop was not quite square, the specification was a .078" radius, over 1/16". It was increased to 7/32" in January 1918, six years before the A1 suite of modifications.

7. The slide pauses momentarily at full rearward travel.

John mentioned this but I will expand. The slide rebounds rather smartly off the recoil spring guide flange which is supported by its abutment in the frame. The delay required for the next cartridge to come up to the top of the magazine is the time it takes the breechface of the slide to pass from the cartridge rim to its rearmost position, rebound and return under recoil spring force to strip the top cartridge. This is why shortened mutant designs are so sensitive to good magazine springs, to get the round up in the reduced travel time.

[WVsig]

Where is 1911tuner when you need him.

[WVsig]

If 1911tuner was still active I am sure he would have some thoughts on this post.

https://www.youtube.com/watch?v=Xyis5h9MvUU

[Aguila Blanca]

Originally Posted by Josh Smith

Inertial firing from forward momentum imparted by the slide.

I thought that was clear from the context. Wasn't it?

No, your statement was inherently incorrect, so it could not have been clear from the context. Inertial firing is inertial firing. The 1911 mode of operation is via an inertial firing pin, so obviously the firing pin spring does not prevent inertial firing. What you mean is that the spring helps prevent slam firing.

[Josh Smith]

Re: Tuner

I actually found him, and we've engaged in discussion.

Sure, you can fire the 1911 without the return spring. I just didn't advise it.

- Hypothetically, on a Government, the hammer and mainspring should provide all the control needed to retard unlocking of the slide/barrel assembly. This is theoretical and I wouldn't try it.

I don't know what condition your particular 1911 is in, and I'm not going to come close to recommending you try this.

Sure, it probably wouldn't hurt, and the vid (is that Tuner doing the shooting?) shows that in that particular 1911 is just fine.

I don't know that someone won't try this with a short link, though, that just happens to bust at the same time, then make an issue out of it whether it would have failed with a spring or not.

That's my whole "cover my ass" reasoning. I don't want someone to try it, have his gun bust, and then point and me and say, "But but but he SAID it was OK!"

Regards,

Josh

[Josh Smith]

Originally Posted by Aguila Blanca

No, your statement was inherently incorrect, so it could not have been clear from the context. Inertial firing is inertial firing. The 1911 mode of operation is via an inertial firing pin, so obviously the firing pin spring does not prevent inertial firing. What you mean is that the spring helps prevent slam firing.

Originally Posted by Josh Smith

All's well, right? Well, no. Remember inertia? Your firing pin is an inertial firing pin, meaning it cannot touch the round's primer and the hammer at the same time.

So, now that we have forward inertia, the inertial firing pin slams into the round's primer as soon as the slide and barrel lock and slam suddenly to a stop. Buuuuuuuurrrrrrrrrrrrrp! A firing pin in motion tends to stay in motion, and all that. The feds frown on runaway guns as fully auto.

Therefore, the firing pin must have a spring to arrest its forward inertia, as well. In addition, a strong firing pin spring keeps firing pin wipe from happening: The firing pin must not be in contact with the primer when the spent round is ejected.

I described slamfire...

Josh

[44 AMP]

I would give you a "B".

"A" for effort and intent, but only a "C" for technical accuracy, and for use of language to clearly convey ideas.

The proper function of a semi automatic pistol is a complicated balancing act of many factors. Focusing on the role of the springs alone gives a misleading impression when describing the function of the pistol.

Several statements were not entirely accurate, but I was unable to tell if that was because of an actual misunderstanding of the concept, or the writing not giving me a clear idea of what your understanding of the concept actually is.

I'd be happy to explain my reasoning point by point, in either public or private, if anyone wishes to hear it.

[T. O'Heir]

"...which are used to store energy for operation..." Most springs in a 1911/1911A1 are there to return the part to whence it came after firing. Not provide function by string energy. The main spring is an exception. It provides 'power' to the hammer by being compressed when the hammer is back. There isn't enough power in the main spring to stop the slide doing anything. The main spring isn't connected to the slide.
The return spring is called that for a reason. It returns the slide to its closed position.

[Walt Sherrill]

Originally Posted by Josh Smith

Let us for a moment consider only the mainspring. Imagine a 1911 with no return spring nor firing pin spring. Imagine a round chambered and full magazine loaded into this hypothetical pistol.

When you squeeze the trigger, these events happen:

1. The hammer drops, striking the firing pin.

A question and some thoughts/observations:

If the mainspring is removed, is there enough force driving the hammer to ignite the primer? (The force of the hammer has to overcome the firing pin spring, and move the firing pin with enough force to bridge the gap between its resting position and primer.) I'm not sure you can get there from here...

Originally Posted by Josh Smith

- The greater the amount of energy stored, the more force the recoil return spring will exert against the force of recoil. This means that the heavier the recoil return spring, the greater the feel of the recoil imparted to your hand.

I think felt recoil isn't so easily explained. The amount of recoil being handled is based on the round, and a heavier recoil spring slows things down a bit, and stores a bit more of it to be used to close the slide. The force transfer is delayed going in, as it's stored, and a bit more is returned as the slide shuts.

In all such cases, the amount of force stored isn't really that great. As 1911Tuner has shown (here and on YouTube), running a 1911 without a recoil spring doesn't really cause damage, and most shooters don't really notice THAT MUCH difference in the recoil experience -- certainly far less than they expected. Without the spring, the gun doesn't cycle; it also doesn't self destruct. Controlling recoil is a small part of the recoil springs duty -- which is why JMB called it a return spring, I guess.

I've not seen any tests using proper measuring methods or devices to actually track the force going to the grip as around is fired when different weight springs are used, or to measure the effect of the slide slamming forward with slightly more or less force, depending on spring weight. (It can be measured, and I've seen it done in other tests, but not with recoil spring variations.)

A light recoil spring would let a bit more of the recoil force pass to the shooter (as less is stored in the spring), and the slide would cycle a bit more quickly; a heavier spring would slow the slide down a bit as it moves to the rear, storing a bit more of that force, and using it when the slide slams forward (with a bit more force.) I suspect the DURATION of the recoil experience would be the biggest felt difference. A sharp snap vs. a longer push might be experienced with some springs.

I know that some professional shooters go to lighter recoil springs and buffers to let the slide cycle more quickly, but doing so also lets them control muzzle rise. Felt recoil is seldom mentioned.

[Josh Smith]

Correct.

The recoil return spring does not control recoil to any great extent.

I stated that clearly. It returns the slide from its recoil position.

- Take away from this that the primary recoil and barrel/slide lockup timing control is the mainspring, NOT the "recoil" (slide return) spring.

I think I see where the confusion is coming in.

I'm stating the dwell time as a function of time, not distance. The more effort it takes to cock the hammer against the mainspring, the longer the dwell time.

Josh

[Josh Smith]

Originally Posted by "T O'Heir"

"...which are used to store energy for operation..." Most springs in a 1911/1911A1 are there to return the part to whence it came after firing. Not provide function by string energy.

The recoil return spring stores energy during the recoil phase to power

1. Loading
2. Lockup

during the loading phase.

If it didn't store this energy, then it would not return the slide. I'm not sure where the confusion is.

The main spring is an exception. It provides 'power' to the hammer by being compressed when the hammer is back. There isn't enough power in the main spring to stop the slide doing anything.

Sure there is. Any load reduces velocity.

Measure the velocity of a car on a straightaway with a certain throttle position.

If you put a 2000lb load on that same car, give it the same throttle position under the same conditions, it will take longer to reach top speed and the top speed will be slower than without the load.

The main spring isn't connected to the slide.

Of course it is. Via the hammer, via the strut via the cap. Just like the recoil return spring isn't connected directly to the slide, but rather through its cap, through the barrel bushing.

The return spring is called that for a reason. It returns the slide to its closed position.

Of course.

Josh

[James K]

Sorry, but the original information is, at best incomplete and is partly flat out wrong, as are some of the comments. I won't even attempt to discuss each error, but some experience and knowledge, such as a high school level physics course, would be needed. A quick look at some "coffee table book" pictures won't cut it. For example, the OP seems to not really understand a locked breech, why it is needed and why not all "auto" pistols use it, something that would seem necessary to even begin to understand the functioning of such pistols.

Jim

[Josh Smith]

Sorry, but the original information is, at best incomplete and is partly flat out wrong, as are some of the comments. I won't even attempt to discuss each error, but some experience and knowledge, such as a high school level physics course, would be needed. A quick look at some "coffee table book" pictures won't cut it. For example, the OP seems to not really understand a locked breech, why it is needed and why not all "auto" pistols use it, something that would seem necessary to even begin to understand the functioning of such pistols.

Please do.

How am I demonstrating a lack of understand of the locked breech? Or physics, for that matter? Please elaborate.

Josh

[Walt Sherrill]

Originally Posted by Josh Smith

-Take away from this that the primary recoil and barrel/slide lockup timing control is the mainspring, NOT the "recoil" (slide return) spring.

The mainspring is compressed by the hammer, which is cocked by slide movement after a round is fired. The mainspring remains compressed until the trigger is pulled with the next shot.

Lockup, however, occurs as the slide chambers the next round -- which happens WHILE the hammer is locked back and the mainspring remains compressed. A heavier mainspring won't make the gun lockup any differently than a light one, nor will a heavier or lighter recoil spring. If the rounds used are sufficiently powerful to properly cycle the gun, things will still work. It works because of the stored force in the recoil spring!

A DAO version of a 1911, if you (for some strange reason) wanted one, would still cycle and lockup, but the mainspring would still play basically the same role it plays in a SA 1911: powering the hammer!

Timing is the term used in these discussions, but the key relationships are physical ones -- how the various parts fit together and interact. The SPEED with which they interact are generally unimportant, as they can cycle faster than we can pull the trigger. Those physical relationships are NOT controlled by springs. The recoil spring (using stored recoil force) powers the parts -- but the slide powered by recoil charges the mainspring.

[44 AMP]

How am I demonstrating a lack of understand of the locked breech? Or physics, for that matter? Please elaborate.

Since you asked...

lets start with this point,

Sure there is. Any load reduces velocity.

I was having a difficult time understanding why you felt the mainspring held the slide closed, until you said this. Your example of the car, taking longer under a heavier load is what a car does, but doesn't quite apply the same way to the slide of a pistol, in any practical manner.

The function of the mainspring is to power the hammer, and the force required by the slide to overcome the at rest tension of the spring, and then compress it is a constant, and something vastly overcompensated for by the energy of the slide during recoil.

I'm stating the dwell time as a function of time, not distance. The more effort it takes to cock the hammer against the mainspring, the longer the dwell time.

This is indeed a point of confusion. If I'm understanding you correctly, you are saying that without the resistance of cocking the hammer, the slide would move faster, and therefore, the mainspring "holds the slide closed" for a tiny amount of time.

OK, I get that. However, without covering the other things that ALSO "hold the slide closed" and by only looking at time as "dwell" and not time/distance, your statement implies that it is only the mainspring's resistance to compression that "holds the slide closed", which is, not the case.

Pardon the pun, but your explanation of the slide unlock sequence has a "missing LINK".

Yes, there is some resistance to rearward slide movement from the hammer at rest, the difference you can feel, simply cycling the slide with the hammer down, and again with the hammer cocked. It's not a lot of force, compared to the recoil energy of the slide.

IF you were to remove the mainspring's effect on "holding the slide closed", it would make NO DIFFERENCE AT ALL to the slide opening (unlocking from the barrel). The slide and barrel unlocking is a matter of DISTANCE, NOT spring resistance. When the barrel, running backward, locked with the slide, hits the end of the link's travel, the geometry of the angles of the parts yanks the rear of the barrel down, away from the slide, unlocking the two.

The point in TIME that this happens can be very slightly affected by changing the amount of spring tension needed to be overcome (and remember to include the resistance of the recoil spring, as it compresses and loads up), what you are calling "dwell", but the point in the movement of the slide and barrel that they unlock is always going to be the same.

Going to a heavier or lighter spring set is going to change the time by a tiny fraction of a second but does not, and cannot change the point of movement where unlocking occurs.

Another point, not clearly pointed out, is how springs "store" energy.

- The greater the amount of energy stored, the more force the recoil return spring will exert against the force of recoil. This means that the heavier the recoil return spring, the greater the feel of the recoil imparted to your hand.

yes, BUT, this only applies when comparing different springs, to each other, in their response to compression. Compress an 18lb spring with 300lbs force, and you have 18lbs potential energy stored. Compress a 25lb spring and you have 25lbs. ALL the excess is pass on as "felt" recoil. And the 300lb source doesn't notice the difference, either. The gun has many times the power to do either spring, so there is no practical difference, IF YOU STAY WITHIN DESIGN PARAMETERS.

Go far enough outside them, and things change. Go with a heavy enough spring and you don't need a locked breech. But you will need to accept other limitations.

7. The slide pauses momentarily at full rearward travel.

yes, because it hits the frame (recoil spring plug). How HARD it hits depends on different factors, but it does hit. Which is why the "shock buffer" pads some people use wear out and need to be replaced every so often. So, the slide is physically stopped from rearward movement, while the energy moving it is not, and continues reward, again, being felt as recoil. The "pause" is the time it takes for that energy to drop below the force stored in the recoil spring. When that happens, the spring moves the slide forward, again.

8. The slide begins forward under the stored power of the recoil return spring. Before the slide can get up much forward velocity, it is slowed again as it strips the next round from the magazine. This is very important.

9. Due to the engineered slowing of the slide, it comes forward to a soft stop.

- This is why it's OK to chamber a round from a magazine, but not to drop the slide on an empty chamber! A slide dropped on an empty chamber is not slowed and will batter the lugs and cause the sear to bounce. It strains the gun.

The "soft stop" you get when chambering a round is an additional reason to only load through the magazine, not the main reason, which is to avoid possible damage to the extractor. The 1911 extractor is, like the Mauser 98 extractor, not designed to snap over the rim of a chambered round. It is designed to have the rim fed up underneath it as the action closes. IN an EMERGENCY, they can be forced over the rim of a chambered round, but they might be damaged or completely break if this is done.

(modifications to the gun to allow the extractor to snap over the rim were not part of the original design, though they have become common since.)

As to the "hard stop" of letting the slide slam shut empty, this practice has been found to be detrimental to some highly tuned competition type guns. However, these guns all do vary from the GI specs, in several ways.

I've never found a GI spec 1911or A1 damaged due to any amount of letting the slide slam shut empty, and I used to inspect them for the Army. Simply put, the GI spec guns were built to take the abuse, and not fail, something a highly tuned customized gun usually isn't.