Strength of slide return spring in a 1911

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......There is nothing theoretical about the principle of conservation of momentum and all of the forces acting on the slide and bullet are taken into account by conservation of momentum......


I'm still struggling to understand all the bits and pieces, and I fully accept the "conservation of momentum", but if all that momentum was going into the slide, somebody couldn't resist all that energy just by wrapping their fingers around the slide. ...if I understand what all of you are saying, that "momentum" is going into the shooter's hands. Hold the slide as shown in that video, and the slide doesn't move at all.

It looks more and more like just enough energy is going into the slide, to allow it to eject the spent case, and cock the hammer for the next shot, and even that energy is going into the shooter's hands.



A question for you guys - if you suspended the gun from the ceiling with a string, and had something attached to the gun, that pulled the trigger to fire the gun, would the slide move at all, and if so, how much? I think the bullet would go flying out the front, the gun would swing backwards to the rear, and the slide would only move slightly, resisting the mass of the gun having to accelerate towards the rear.

...........then again, it's 2:30am, and maybe this will look different to me in the morning!
 
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Originally Posted by JohnKSa View Post
......There is nothing theoretical about the principle of conservation of momentum and all of the forces acting on the slide and bullet are taken into account by conservation of momentum

I'm not arguing or denying the principles of the conservation of mementum...but momentum has to be established before it can be conserved...and if motion is impeded before full velocity is reached, full momentum is never established.

If you jump from an airplane at 10,000 feet, and open a parachute before reaching terminal velocity, you'll never reach terminal velocity, and thus never establish the momentum that comes with terminal velocity. Yes? No?

If the slide assembly...the gun...encounters an outside force that the bullet isn't also subject to before it reaches full velocity, its momentum will not be equal to the bullet's because it will never reach its full theoretical velocity.

Once the bullet has cleared the muzzle, it encounters the air...an outside force...and it immediately starts to lose velocity and momentum. Why would the slide not be subject to the same physical laws? There are three outside forces impeding its acceleration the instant that it starts to move. The recoil spring. The hammer's mass. The mainspring.

But once again, we've strayed so far from the original questions that the OP has probably lost interest...so I'll stop responding.

if you suspended the gun from the ceiling with a string, and had something attached to the gun, that pulled the trigger to fire the gun, would the slide move at all,

Depends on the recoil/action spring. If the slide isn't oversprung, it will likely make the full trip or nearly so. Correctly sprung, the slide should cycle when cradled loosely in the hand on top of the thumb and forefinger, with the wrist bent and held as limply as possible. If it doesn't...it's oversprung.

Then, the slide should strip a round and chamber it reliably. If it doesn't...you have other issues in play. If the gun is functioning properly, it should feed and go to battery by pushing on the rear of the slide with the tip of one finger.
 
Let's do a hypothetical to illustrate the difference between muzzle velocity and rate of acceleration. I love hypotheticals because the only limit is the imagination.

We have two .44 Magnum revolvers. One has a 2-inch barrel, and the other a 10-inch barrel. For the sake of argument, let's assume that they both weigh exactly the same.

Both will be fired with identical 240-grain bullets.

The cartridge for the 2-inch gun is loaded with a powder that will produce exactly1200 fps.

The 10-inch gun will be loaded with a powder that will also produce exactly 1200 fps.

Let's assume that bullet acceleration is linear in both.

Muzzle velocity is the same, so momentum is the same with both rounds.

But...

The rate of acceleration in the 10-inch barrel is 120 fps per inch.

The rate of acceleration in the 2-inch barrel is 600fps per inch.

Which revolver will be more unpleasant to fire?

And this is why recoil isn't determined solely by muzzle velocity.
 
Unfortunately, there's a fly in the equal-velocity/long-vs-short barrel argument.

1. The first problem is that a cartridge to achieve 1,200fps out of a 10" barrel is an
entirely different animal than req'd one that will hit that 1,200 out of a 2" snubnose
-- literally apples vs watermelons

2. Any 357 cartridge fired in a short barrel will undergo the same initial acceleration
as one fired in the long barrel. Acceleration will cease earlier in the short barrel
(and therefore net work done/recoil generated is actually less in the short gun).

3. BUT... a short-barreled 357 will most times weigh near only half that of a
long barreled revolver, AND the rocket/jet effect of burning powder exiting the
muzzle is significantly greater.

MV is preserved within both systems, as is total energy (much to the unpleasant
pain for the snubbyshooter) ;)

~~~~~~~~~~ BREAK BREAK ~~~~~~~~~

As to free recoil vs anchored recoil of a "hanging-in-space" gun...

A 1911 comes in two parts: slide (for grins say 2-lbs), and a frame that weighs
half that for a total of a 3-lb "system"

Do the energy equation* for the frame held stationary and the recoil
of a 230gr hardball will start that 2-lb slide moving rearward at 14 ft/sec.
Limpwrist the frame (and presume the spring/hammer/linkage will keep things
together at the start) and the recoil will start the whole gun back at
only 9 ft/sec.

Is there any reason not to understand why limpwristing causes stovepipe jams ?

But finally we come to the fact that a spring whose only job is to return the slide to
battery really only needs to be (literally) a couple of lbs -- maybe not even that.
Why then does the gun manufacturer install a 16-18lb spring at all?
 
Much has been said in this tread about the impedance of the slide that is offered by the hammer, hammer spring, friction offered by the slide rails, and the recoil spring. I understand all that.

My understanding of the functioning of the 1911 pistol, is that upon discharge the slide and the barrel do not unlock from the locking lugs immediately, but rather only after the bullet leaves the muzzle.

Does this not play a significant role in the M1V1 Vs M2V2 equation as regards the rearward velocity of the slide during the initial firing phase, such that the initial momentum of the bullet as it transits the barrel gets transferred to the whole body of the pistol and only the velocity of the mass ejecta as it leaves the barrel acts on the slide after it unlocks from the locking lugs?

If my understanding is in error, please educate me?
 
1911tuner,

uh, acceleration units are in feet per second per second, not feet per second per inch. also, momentum is mass times delta velocity (the difference in the velocities measured at point A (bullet in barrel before firing) and measured at point B (bullet at muzzle)). so, since velocity at point A is always zero, we can calculate momentum using bullet weight times muzzle velocity.

if bullet weight and muzzle velocity is the same in both guns in your scenario, then the momentums will be the same in both guns (at the muzzle).

murf
 
upon discharge the slide and the barrel do not unlock from the locking lugs
immediately, but rather only after the bullet leaves the muzzle. Does this
not play a significant role in the M1V1 Vs M2V2 equation as regards the
rearward velocity of the slide ?
You are correct that the barrel/slide do not unlock immediately, and in fact the barrel/slide stay together
for more that 20-thousandths movement until the link angle changes enough for the frame-anchor pin
to drag everything down. Until that point, the slide and barrel mass are moving as a single unit.

But then the frame stops the relatively light barrel (transferring its mv into the shooter's hand), leaving
the much heavier slide to go it's merry way.
 
1. The first problem is that a cartridge to achieve 1,200fps out of a 10" barrel is an
entirely different animal than req'd one that will hit that 1,200 out of a 2" snubnose
-- literally apples vs watermelons

2. Any 357 cartridge fired in a short barrel will undergo the same initial acceleration
as one fired in the long barrel. Acceleration will cease earlier in the short barrel

Any 357 cartridge fired in a short barrel will undergo the same initial acceleration
as one fired in the long barrel. Acceleration will cease earlier in the short barrel


Yes. That's why I said that it's a hypothetical...and that we're assuming that acceleration is linear.

And I mentioned that a fast powder would be used for the short barrel and a slow powder for the longer one. You haven't read it carefully.

uh, acceleration units are in feet per second per second, not feet per second per inch.

That's why I qualified it with "RATE" of acceleration. Remember that this is a hypothetical...for illustrative purposes. If the bullet achieves 1200 fps in the short barrel, ya gotta kick it harder and accelerate it faster than in the longer barrel. Think of a sharp punch as opposed to a push. The end result is the same, but the way it's achieved is different.

if bullet weight and muzzle velocity is the same in both guns in your scenario, then the momentums will be the same in both guns (at the muzzle).

I said that the momentums are equal. Nobody's arguing that. The rate of acceleration is not...because the force requirements to achieve those rates in different barrel lengths are different. The whole point is that recoil isn't momentum. It's acceleration...and muzzle velocity is only part of the picture.

(and therefore net work done/recoil generated is actually less in the short gun).

If you believe that, I suggest loading a 158-grain bullet to 1200 fps in a 2.5-inch Model 19 with Bullseye, and the same bullet to the same velocity in a 6-inch Model 19 with 2400. Doable, if right on the peg pressure-wise. And don't be misled by muzzle blast. Go by the sting in your hand.
 
I called Les Baer Custom to ask their advice. Les got on the phone himself. I told him the three loads I expect to shoot in my Premiere II are:
  • 230gr FMJ Winchester White Box
  • 230gr FMJ with 5.2gr Unique
  • 185gr Speer bullets with the lightest load for Unique powder (eventually)

Les said I should only use the stock 18# spring for everything. The only time I might want to change to a weaker spring is if a lighter load doesn't allow the gun to cycle properly.

He also said that ejecting the cases about 18 feet is normal. ....and to ignore all the nonsense on the internet.



I'm still interested in this discussion, as it provides a better understanding of what is going on, but I plan to re-install the 18# spring and leave it there.
 
if a lighter load doesn't allow the gun to cycle properly.....
The Bottom Line (literally). :neener:

Shoot it, and let us know. ;) :D :D




BTW: QL (calibrated against Lyman predicted velocities), predicts that 230FMJ/Unique/5.2 load goes out a 5" muzzle at 670fps/230ft-lbs.
I'd most interested to know how that compares to the 12# spring indicated by the chart in Post 45
 
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Hi, Mike. It's me. Interesting thread. Now that everyone may be somewhat confused as to what to do here, I can offer two bits of advice. One, you have made no mention of "cutting coils" on any springs....GOOD! that is a bad idea, if one needs a lighter spring, buy one!

The other point is simple. Tuner is quite right about the function of the recoil spring. Forget about "spring weights" and all of that. Simply put in a spring that has enough power to reliably feed rounds out of the magazine. That's it! It is no more complicated than that!

Glad to hear the Webley is chugging along, albeit a bit loosely.

Good shooting.
 
if one needs a lighter spring, buy one!

The availability of varied spring ratings makes that both convenient and possible...but back in the dead days before they were readily available, recoil springs were trimmed regularly in order to get the slide to cycle with light or "target" loads. Colt Gold Cups and their predecessors were delivered with two springs. One for hardball and one for "softball" ammunition. The softball springs were identical to the hardball springs in every way except the number of active coils. The hardball spring had 32.5 and the "softball" spring had 28.

Since I haven't seen a NIB Gold Cup in over 25 years, I don't know if they still do that. Somebody else may be able to offer something.

As a point of interest...in those dear, dead days...I had access to a lot of new Colt Government Models and Commanders and I had occasion to test the springs in new, unfired pistols. When all the hoorah about frame damage started in the early 80s, I tested the several springs. I never found a Government Model with a 16 pound spring, and I never found a Commander with an 18-pound spring. They averaged right around 14.5 and 16.5 respectively...and the last ones that I tested about 12 years ago were the same.

And, when Springfield introduced the GI Mil Spec, I tested the springs in those, too...the ones with the dab of yellow paint on the closed end. They averaged 14 pounds.

So, it doesn't seem that Colt and Springfield are very concerned with frame damage from slide impact, either.

One of my little tricks for Commanders with standard recoil systems is to cut a 32-turn Wolff 16-pound Government Model spring to 24.5 coils. I've been doing that for over 30 years. Works like a charm and they cut the cost by about half that of Commander specific springs.

Incidentally, the reason that springs are described in "pounds" is because it's easy for everybody to understand and remember. It's the spring's rate...or the amount of resistance per inch of compression that actually means something...but if they were described that way on the package, confusion would reign. So...they give us pounds at full compression, which is actually compressed to a specified length which escapes me at the moment...which tells you how much thought I give to "recoil" springs. I stick as closely as I can to Browning's original specs, and Wolff's 14-pound spring is as close as I can get.
 
Simply put in a spring that has enough power
to reliably feed rounds out of the magazine.
A simple 10#(and less) spring will do that for full-up GI hardball and better.
So again, why do gunmakers insist on installing 16-18# springs ?
(`tis a puzzlement)
 
So again, why do gunmakers insist on installing 16-18# springs ?
(`tis a puzzlement)

Probably for the same reasons that the original spring was 14.5 pounds...nominally. To make sure that the slide will return to battery even when the gun is dirty, dry, and/or neglected. Not everybody takes meticulous care of their guns.
 
Back in the dark days of the last century - 1960's 70's that is... :uhoh:

The US Army's Springfield Arsenal (and later Rock Island Arsenal) turned out match grade versions of the well known 1911A1 .45 Pistol. These were met for Bullseye Competition at 25 and 50 yards, and were designed to function with either 185 grain mid-range ammunition or 230 grain USGI hardball.

Slight modifications were made to the barrel throat and magazine lips, but the recoil springs were unaltered and came from Service Pistol inventories.

And the guns functioned fine with either load. :cool:
 
Thanks for all the info, guys! I'm learning a lot.[emoji106]
 
Probably for the same reasons that the original spring was 14.5 pounds...nominally. To make sure that the slide will return to battery even when the gun is dirty, dry, and/or neglected. Not everybody takes meticulous care of their guns.

I was thinking about this earlier. several years ago I was shooting with a buddy. He handed me his 1911 carry gun. when I shot it, it seemed really odd at first. I shot it again, the slide was taking about 1-2 seconds to fully close, it was like slow motion. I showed him, we laughed. I pulled the dipstick from my truck and oiled it, it ran fine. No idea how long since it had been cleaned. It was very dry though.

This discussion has been very interesting, thank you to all the well informed participants that shared their knowledge. I've always liked the 1911 type pistols, but I think I appreciate them a bit more after reading this. Seeing that one would function with no spring was quite interesting.

I'm thinking the main point of the spring weight for general use is being sure the gun closes when dirty/cold etc. I had a 1968 made Colt National Match (Gold Cup). It wouldnt always fully close. I installed an 18 lb spring, and it worked reliably. I think it was just a bit tight. I never tried any other springs after that, just shot it with standard level loads.
 
I await Mike's trials with his 230gr/Unique/5.2gr loads. ;) :D


That I can already tell you. The gun worked perfectly with the original 18# spring and Winchester White Box 230gr FMJ. When I started shooting my reloads, 5.2gr Unique, there was no difference in function - but a nice decrease in recoil.

People at my club suggested I use a lighter spring with the lighter loads, and Brenda at Les Baer told me I could use a 15# spring, which is now in the gun. As far as I can tell, there is no difference whatever, other than it seeming to be easier to rack the slide now.

Cases were always landing about 18 feet away, with any of the above combinations. That matches what 1911tuner suggested, that this depends on the gun, not the spring.

Les Baer wasn't interested in what I was suggesting - for the loads I told him I was using, he said to use the 18# stock spring, and to always use it unless/until the gun won't cycle properly, and only then to go to a lighter spring. I will be re-installing the stock (18#) spring next time I take the gun apart.



All of this makes sense to me now, from what 1911tuner posted about the purpose of the spring. If the gun is cycling properly, and ejecting the cases properly, my previous thoughts about why I should change to a lighter spring no longer apply.


I have several boxes of 185gr Speer bullets, which I plan to eventually be using. When I get time, I'll load up some of them, and try with the 18# spring still in the gun.
 
Hey! If it works, it works. ;)
(But as you can see from the chart, it did not work with that pistol) :confused::mad:
 
I meant this video, which shows how the slide doesn't have to move at all, if held back with a finger.
When you hold the slide closed, the slide doesn't reciprocate with respect to the frame, but it does move in recoil with the gun and the shooter's hand. The momentum initially goes into the slide and barrel since they are locked together. They will, as a result, initially have the same velocity until something impedes one or the other.
... full momentum is never established.
This is a statement that demonstrates a fundamental lack of understanding of the science behind this topic.

"Full momentum" is determined by the momentum of the bullet at the instant it exits the barrel. However much that momentum is, that is the "full momentum". Saying it can't be established doesn't make any sense.
If the slide assembly...the gun...encounters an outside force that the bullet isn't also subject to before it reaches full velocity, its momentum will not be equal to the bullet's because it will never reach its full theoretical velocity.
The slide and bullet's momentum WILL be equal at the point of bullet exit. That's what conservation of momentum is--that's how it works.
Once the bullet has cleared the muzzle, it encounters the air...an outside force...and it immediately starts to lose velocity and momentum. Why would the slide not be subject to the same physical laws?
It IS! However, that happens AFTER the two are no longer in contact. While they ARE in contact, conservation of momentum applies. Once they are no longer in contact, the momentums can and will diverge.
Which revolver will be more unpleasant to fire?
Felt recoil is not the same thing as momentum.

You are certainly correct that the acceleration rate will affect felt recoil, but that doesn't mean that conservation of momentum as it applies to recoil doesn't work. If you want to know what the slide velocity will be, all you need to know is the mass and velocity of the bullet at the point it exits the bore (and the mass of the slide plus barrel). If you're trying to determine "felt recoil" then that's a completely different (and more complicated) problem.
The whole point is that recoil isn't momentum.
Recoil IS momentum. Felt recoil is another thing entirely although momentum will still play a role.
 
The slide and bullet's momentum WILL be equal at the point of bullet exit. That's what conservation of momentum is--that's how it works.

Momentum will be conserved unless an outside force...and you know the rest.

It IS! However, that happens AFTER the two are no longer in contact. While they ARE in contact, conservation of momentum applies. Once they are no longer in contact, the momentums can and will diverge.

You're still trying to ignore the outside forces that the slide encounters the instant it starts to move...forces that the bullet is not also subject to. And once the slide has lost speed and momentum to those outside forces, it can never get them back, and they can't "diverge" unless a NEW FORCE appears....and a new force isn't available.

Equal momentum is only possible in the absence of outside force, or in the presence of equal outside force. Thus, it's theoretical in a real gun firing real ammunition.

Go back to the rifle mounted in a steel block analogy, John. If the rifle never moves, it never develops ANY momentum...so how can the momentums be equal? Even a rifle fired from your shoulder doesn't develop equal momentum because you are the outside force that keeps it from happening.

In order to develop equal momentum, the rifle would have to be fired while levitated in the air, with nothing resisting its acceleration.

Felt recoil is not the same thing as momentum.

Recoil isn't momentum at all, but I've said that all along. You keep trying to bring momentum into the argument.

Recoil is acceleration, and it occurs so quickly that it's over before our brains realize it's begun. The only clue that it ever happened is the sting in our hands and shoulders from the impulse. What we recognize as recoil is momentum...movement after the acceleration...the action and reaction...has ended. But that's not recoil. Recoil is only in play as long as the bullet is still in the barrel and being accelerated.

Let's revisit acceleration and see how it applies.

Another hypothetical that we can all understand.

A car from my past...a 1969 428 Cobra Jet Mustang...could accelerate from 0-100 in a quarter mile pretty much on demand. It was an exciting ride for the day, and I made that trip several times.

Accelerate the same car from 0-100 in a half mile, and the end result was exactly the same. i.e The car was still moving 100 mph, but the ride wasn't nearly as exhilarating.

BUT! If, during a dash toward 100 mph in a quarter mile, I stabbed the brake pedal for a half second the instant that I hit the gas pedal...the car wouldn't have reached the 100 mph mark...because an OUTSIDE FORCE would have interfered with its acceleration and ultimately its speed and momentum.
 
MikeMyers said:
I've lost track. Which chart are you referring to?
(...and who created the chart?)
See Chart in Post 45.

It was created from actual field data/multiple tests at multiple range sessions done from July through September 2011 on the Gov't 1911 shown beside it in the picture.*

The gun was tested over several magazine's worth of each of the loads shown, and the springs replaced (going sequentially lower) until the slide would fully function/pick up the next round, and correctly lock back on the empty magazine each and every time.

Were it just one load, or two, I'd call it anecdotal. But it was four loads that included two different powders, two different weight bullets, and four different springs -- and produced a sequence having a spring-vs-energy correlation factor of .974 (1.0 being statistically perfect).

as to who...

C'est moi! C'est moi!
I'm forced to admit
'Tis I, I humbly reply
That mortal who
These marvels can do
C'est moi, c'est moi, 'tis I...
:D






* I keep a hard-bound lab notebook on each weapon. `Easier to prevent getting screwed up in handloading over the years. ;)
.
 
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