Home Forums Hunting & Shooting Handguns Roles of Springs in the Recoil and Feeding of the 1911 Government

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

Nice analyst but I am not sure of this...

"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've always found the opposite...

Bob

Roger that, at least in my limited experience.
Bob

Good job Josh.

But,Side note.
The Calvary was the first ones to complain about the square bottom firing pin stop. While on horseback they were having problems cocking the slide.

Again, good job.

I think it's highly subjective, and depends a lot on the configuration of the 1911. Going with the softer recoil spring and squared fps makes a GI style 1911 "feel" like less recoil in my hands, but doing same in a modern 1911 with undercut trigger guard and btgs does not.

If the slide is slamming into the frame, it's going to feel worse, regardless. Going with lighter recoil without increasing the resistance at the hammer can do that. Having a reduced mainspring (as some do to improve the trigger) can make it worse.

But my experience is even more limited than y'all's - so I could just be out to lunch.

Josh is mostly correct, except that the "feel of recoil" is not only from force against the spring, but also from force of the slide impacting the frame at the rear limit of travel.

With a softer recoil spring, you get more impact against the frame. With a heavier spring, you get more resistance against the spring, but less against the frame. How this is perceived as recoil depends on the person IMO. A heavier spring also slams the slide closed harder, and some people perceive that as part of the recoil as well, even though it's in the opposite direction.

The force during the "Dwell Time" is the first momentum force transfer.

850 FPS using Titegroup feels hotter than 850 FPS using Unique.

By the way, the 1911 was designed using Unique. Both the 200gr and 230gr loads.

Josh,

You pretty much described JMB's tilting barrel design which encompasses almost every locked breech pistol ever made - Modern plastic included.

What separates the 1911 from most designs is controlled feed.

The lack of a hammer and hammer spring is a big factor in modern striker fired locked breech actions too. That changes the mechanics of the dwell time, and our ability as consumers to tune it.

Yeah, that's something I wonder about. I have one of the early Kahrs that has always left a slight swipe mark on the primers from day one, no matter what I use for a load and no matter how fresh the recoil spring is. Could have something to do with that great trigger, but there's apparently nothing I can do about it.....and probably, it's not a good idea to even try.

”Dwell” time is determined by the barrel cam, and the weight of the slide; but mostly the barrel cam. You cannot extend dwell time to any significant degree for the purposes of making the gun safe to open with the mainspring or the recoil spring. The effects of the recoil and mainspring are very significant in other areas, but the dwell time is based purely on how much time the barrel and slide are LOCKED together, and that timing is purely a function of the barrel cam design. Example: If you had a handgun that opened up pre-maturely and was blowing cases due to pressure being too high, changing the mainspring or recoil spring, within spring weights that are still practical, will not be sufficient to increase the dwell time long enough to make the gun safe. Locked breech handguns can safely fire most cartridges with no mainspring or recoil spring. Now “safely” comes with a big *. Safe in the sense that it won’t blow the case, but not necessarily “safe” from doing damage to the gun in other ways. Within the practical limits of where recoil and hammer springs operate (weight wise), they just don’t have a significant role in dwell time. But they do play a very small role, and the way they affect dwell is all for the better.

Your “takeaway” point was a technical one, but I gather the message in its entirety also touches on how springs can affect perceived recoil, and in that light, changes to the mainspring and firing pin stop can have an effect for some shooters.

This is a difference between actual physics and perceived recoil. My understanding of the physics is there is no change at all, the full recoil force is determined only by the overall weight of the firearm. But the PERCEIVED effect of recoil can vary tremendously on various things that spread the recoil out over time, or re-directs the force/direction of the recoil. I’m not going to get into a discussion of perceived recoil, because some perceive things differently than others. For me personally…generally speaking…I perceive less recoil when recoil spring weight is heavier (all else remaining the same)…but that’s just me; I’ve hear it both ways.
This is an issue that brings about Holy Wars when you get a dozen competitive shooters together…especially if they are all drinking.

Good points, but there’s even more going on. The delay for picking up the next round can be to inertia, or it can be to the distance of the stroke of the slide. The Officers ACP is a great example (glad you brought it up). Not only does it have less inertia from having less mass, but the distance the breech face is traveling past the magazine is radically shortened. And the headaches come more from that stroke length than it does from inertia. Like you said, the return trip is coming REAL QUICK on the Officers ACP vs. the Government model. But to make matters worse, not only is the return trip happening very soon, but the breech face is already nearly at the cartridge rim when that return trip starts, making the timing of advancing the next round in the magazine extremely critical. Often when you have an Officers ACP that was working, but then starts to fail to pick up the next round (what many incorrectly label “short stroking”), is actually a worn magazine spring. The slide and recoil spring are still doing their jobs, but the magazine spring has taken a little bit of a “set” and now the magazine isn’t advancing the next round into place in time for the slide’s return trip. A government model can often go it’s entire lifespan with the original springs the gun came with, but you’ll never get away with that on an Officer’s ACP or most any other sub-compact auto pistol .

Just wondering where you got that? I have always read that it was Bullseye. Not that it really matters much, just a curiosity.

I want to say I read about the use of Bullseye in "Handguns of the World: Military Revolvers and Self-loaders from 1870 to 1945" by Edward C. Ezell. That's a classic and very well done book, but no one's perfect. Just wondering where you read that it was Unique?

It could be either one really. Both were invented just before the turn of the 20th century. I think Bullseye was more common, but Unique made a HUGE impact on the handgun & shotgun powder scene because it really was "unique" in its versatility (kinda still is).

Most pistols made today have "controlled feed". There are a few that are "push feeders" as we most commonly use that term. Some of the Walthers and Astra's are push feed (Walther's PP, PPK. Astra 300,400,600,3000, etc...IIRC); with a little tab extension at the bottom of the breech face (which never seemed like a good idea to me, but hey, I'm no engineer).

We're more aware of the controlled feed of the 1911 because the 1911's extractor design is such that it needs to be "tuned" correctly to facilitate proper feeding. Later style extractors such as the ubiquitous external extractor typically either drop in with the correct contact, or you simply file a little tab to achieve proper contact.

But the overwhelming majority of centerfire auto pistols have "controlled round feed".

Hammer spring, striker spring - potAto, potato. Sure, designs differ in the degree the striker is cocked by the slide. Even in a 1911 the main spring is poor choice for tuning.

Simply not correct.

Turn your non-1911 upside-down and slowly chamber a round.

A very old book I have on the Hercules Powder Company (Hercules,Inc) Bullseye was marketed mostly by DuPont which was one of the companies that joined to form Hercules. Bullseye was used in .38 S&W, .380 ACP ,.32 ACP ,exported for 9mm Parabellum (secretly)and others.

AA#5 is the clean modern day versatility king now.IMO

This is going to get long, drawn out, and sufficiently boring to put most anyone to sleep.

Let’s start by mentioning the fact that there are a LOT of 1911’s that won’t pass your upside down test, yet still function just fine. Sure they’re supposed to pass that test BY DESIGN, but they don’t. And the same can be said for a gazillion other pistols. CRF isn’t a make or break issue, even in the 1911.

Agnostic of cartridge, most designers when they design their auto pistol, will state that it should have positive tension on the case rim sufficient to hold the cartridge to the breech face. So most auto pistols, as designed, are supposed to be controlled round feed. But on most pistols it’s just not critical, and since it takes more hand fitting to make the pistol 100% CRF, the manufacturers don’t sweat it.


When it’s important and when it’s not.

On a pistol chambered for a longer straight walled cartridge, extractor tension is more important than it is on shorter straight walled cartridges…and just not necessary on short tapered cartridges.

With just a few exceptions, most all semi-auto pistols are designed such that during feeding the case rim slides under the extractor when the rim releases from the magazine. Tension to actually HOLD it there in place really isn’t all that important during the feeding. When it is important is during extraction.

One of the more common issues I encounter as a gunsmith is a pistol that fails to eject the last round out of most every magazine. And that issue is almost always related to no case tension on the case rim from the extractor. But you RARELY if ever, see that issue with 9mm. And while you do encounter it with .40’s, you get it much less with a .40 than you do with a .45 ACP. What’s happening is the fired case is leaving the chamber area, and when it gets far enough out that it’s no longer being supported by the chamber, the heavy side, which is the back end with the rim, succumbs to gravity and falls down onto the magazine because the extractor isn’t holding the cartridge to the breech face during extraction. And the reason it only happens on the last round is because when the magazine has another round to feed, the empty case is prevented from falling completely away from the extractor by the next round in the magazine. The next round keeps the extracting round up enough that it will be in-line with the ejector, and gets properly kicked out of the gun.

With a 9mm controlled round feed is completely unimportant on most pistols because of the tapered cartridge. Tapered rounds tend to hold tight against the breech face during extraction to the point to where most guns with sharply tapered cartridges don’t need an extractor to function 99% of the time (only when it gets dirty does the extractor start to do its work). So because the empty 9mm case is being held to the breech face by other forces, CRF from the extractor is just unimportant.

And then add in the later extractor designs. They way they’re designed and made is such that it takes less fitting and a less skilled assembler to end up with an extractor that falls into the “working range”. So many non-1911 .45’s, .38 Supers, and 10mm’s you’ll find that many of them will exhibit CRF. While most pistols chambered in the shorter cartridges like 9mm, .357 Sig, and .40 rarely exhibit CRF because it’s just not needed.

Still, as designed, agnostic of cartridge, most every pistol is designed to be CRF as a default. Once the cartridge is added in, then it may or may not remain so.

Agreed, from my POV.

Overall, a nice dissertation by the OP & lots of good comments by a lot of smart people.

I can only say that with regards to springs, is that I will adjust the combination of mainspring weight & recoil spring weight to attain my objectives of using the lightest combination that will reliability function the gun with a reasonable ammo range w/o battering the frame.......using a square bottom FP stop & give me the trigger pull that I want with a given sear/hammer setup without too light a sear spring.

I am not a fan of heavy recoil springs, period & unless shooting an ongoing & limited diet & heavy +P ammo they are simply not needed.

For 185/200 SWC's, 230 ball & most typical 230 SD HP's (HST's GD's, etc), a recoil spring of 16-17 lb. & a mainspring of 19-21 lb. almost never don't work.........assuming all else is as it should be. (16.5 was original spec, IIRC, for recoil springs & 23 is original spec for mainsprings)

As for "felt" recoil, I've always felt that it is (for me) far more of a function of the power factor of the ammo than any possible combination of springs in a given gun; secondarily, the weight of the gun......I can easily tell the difference in recoil (& muzzle rise) of a lightweight framed gun compared to a steel framed gun. Ditto for short slide guns.

I can easily feel the difference between a 230 gr bullet at 750 FPS vs one at 975; same for a 185 at 1,000 PFS, vs the 230 at 975.

JME; YMMV.

MM

I change recoil springs A LOT. I shoot almost every day (except weekends), usually a .45 semi-wadcutter gun and one or two accurized service pistols. Springs wear and will need replacing yearly if you shoot often. That also holds true for a .22 (like an M41 S&W).

On a wad gun with a heavy rib I've found a 10-12 lb spring works well. A ball gun functions with a 16 lb (GI) spring. My experience tells me you can get away with a 14 lb spring with no issues. It also depends on the hammer spring strength, which works OK on a target gun with less than 23 lbs. Think balance. Most hammer springs I use are somewhere between 18-20 lbs. Coupled with a lighter recoil spring I've had no issues.

I talked about this at length with a couple of AMU Armorers at Perry years ago; too much spring translates into hammer/sear damage because the slide slams home too hard. The Army tried 18.5 lb springs as well as shock buffers and went back to lighter springs and no buffers due to no discernible advantages with heavier springs. Too-light (or worn) springs cause malfunctions.

Your goal should be to have a nice pile of brass 6-8 feet from you. Not always possible with ball, but easily achievable with 185-200 grain SWC rounds at less than max velocity.
Bob

It's not potAto, potato, there is a very significant difference. You may not understand it, but it is there.

I also disagree with GunGeek's assertion that the hammer/mainspring does not significantly affect dwell time. Mechanically, the barrel link controls where the slide unlocks in it's travel, sure, but a stiffer mainspring and FBFPS do affect when the slide retracts to that point to unlock in the firing cycle. You can feel the difference when racking the slide, and can see the effect in the brass when comparing both ways with hot loads, like 10mm or 45 Super.