Tuner, I always enjoy reading your posts. After joining the CSF and reading one of your similar observations/lessons, I went back into the CSF "archives" and read what you have written. I can't think of a time when I didn't come away better for the reading of what you had to say.

Todays post serves to confirm what I have suspected a long time: You have forgotten more about 1911's than I believe that I could ever hope to learn! You make me think and I like that. I hope the light bulb going on over my head with this post didn't hurt your eyes too bad.

Thank you for your contributions and sharing your knowledge, logic, and opinions. Keep 'em coming.

 

Good stuff right there.

If tuner ever decides to host anymore 1911 workshops I highly recommend attending one, I think it took my brain a week to process everything I learned.

 

Still thinking through the first part about heavier springs in smaller guns...thought provoking for sure.

Before the energy question comes up, take a look at energy vs momentum as the destructive force.

Compare the 5.56/M193 cartridge to the original .45-70 "Cavalry" load.

55 grains at 3250 fps vs 405 grains at 1300 fps. There is little difference in the respective muzzle energies. Yet, the .45-70 slug will drive through a bull Elk lengthwise, while the .22-caliber pill probably won't get past the heavy chest muscles. Momentum.

Although the .45-70 actually has an 18% energy advantage in this example...interesting point.

What are your thoughts on this example where momentum is equal:

55 grain 5.56 @ 3250 fps vs 185 grain .45acp @ 1000 fps. The .45 has slightly more momentum but I think most would suspect the 5.56 is far more destructive.

 

Another way to look at it is stored energy factors, the fired round emits the energy and the ability to store energy(resistance) is less in the Commander slide thus the remaining energy is stored in the heavier spring. The standard slide will be slightly more reliable in function of the two because the ability to store energy varies at a higher scale as the energy is increased to the spring.

 

What are your thoughts on this example where momentum is equal:

Even at equal momentums, the 55-grain bullet won't penetrate as far in a given medium.
The faster it's moving, the harder a given outside force fights it. The less massive it is at any velocity, the faster it decelerates when it encounters a given outside force. Newton's law of inertia and conservation of momentum in action. High mass resists deceleration more efficiently than low mass, all else assumed to be equal.

Look at ballistic tables for the clue. The faster it hits the air, the faster it slows down...the greater percentage of its initial velocity it loses.

Also...

.308 caliber. A 150 grain bullet at 2800 fps mv vs a 165-grain bullet at 2600 fps mv. Assuming equal ballistic coefficients, or very close...like the Nosler Ballistic Tip design, and assuming that both are fired at the same instant:

At 100 yards, the 150 is kickin' the 165's butt. At 200 yards, the gap is closing. At 300 yards, the velocities are within about 50 fps of each other. At 450, they're neck and neck. At 500 yards, the 165 passes the 150. At 600 yards, the 165 is way out front.

 

Hence the reason heavier bullets are preferred for longer distance shooting.....they lose velocity slower allowing them to be more effective at longer ranges.

 

Even at equal momentums, the 55-grain bullet won't penetrate as far in a given medium.
The faster it's moving, the harder a given outside force fights it. The less massive it is at any velocity, the faster it decelerates when it encounters a given outside force. Newton's law of inertia and conservation of momentum in action. High mass resists deceleration more efficiently than low mass, all else assumed to be equal.

Look at ballistic tables for the clue. The faster it hits the air, the faster it slows down...the greater percentage of its initial velocity it loses.

Also...

.308 caliber. A 150 grain bullet at 2800 fps mv vs a 165-grain bullet at 2600 fps mv. Assuming equal ballistic coefficients, or very close...like the Nosler Ballistic Tip design, and assuming that both are fired at the same instant:

At 100 yards, the 150 is kickin' the 165's butt. At 200 yards, the gap is closing. At 300 yards, the velocities are within about 50 fps of each other. At 450, they're neck and neck. At 500 yards, the 165 passes the 150. At 600 yards, the 165 is way out front.

To wahoos point, I definitely understood that heavier bullets preserve velocity better and are preferable to a point for long range accuracy...and tuners comparison of 150 and 165 bullets makes sense to me.

I was more focused on the destructive power being a result of momentum comment...which is kind of separate from the slide/spring design issue even if it was alluded to in the original post. So I will save that for another thread.

 

Another way to look at it is stored energy factors, the fired round emits the energy and the ability to store energy(resistance) is less in the Commander slide thus the remaining energy is stored in the heavier spring. The standard slide will be slightly more reliable in function of the two because the ability to store energy varies at a higher scale as the energy is increased to the spring.

This is helpful. So essentially we have two situations, using rough numbers and an overly simplified momentum calculation:

Standard slide 16 ozs standard spring 16 lbs = 16 x 16 or momentum of 256
Commander slide 14ozs, commander spring X lbs = 256/14 = 18 lbs spring to get same forward momentum to reliably extract and chamber the cartridge.

Am I following what you and Tuner are getting at?

 

Sorta. The main point was the slide to frame impact myth that the faster, lighter Commander slide needed a heavier spring in order to keep the impact from damaging the frame. It's a popular and widely-held belief, but it's not supported by the physics once we start taking it apart and looking at it from that standpoint.

Over more than 15 years of testing new springs in Colt Commanders and Combat Commanders, I've never had one to test at 18 pounds...nor a Government Model spring that tested ay 16. They generally ran to about 16.5 and 14.5 respectively. Don't know where the notion of 18 pounds as standard for Commanders and 16 for GMs started...but Colt didn't do it.

Aside from that...the heavier springs in Commanders was about returning the slide...not reducing impact...and it never has been.

 

We've had similar discussions on other forums. I agree with 1911Tuner's analysis (not that he needs my confirmation... as his explanations need no confirmation.)

Folks who use heavier springs, on principle, to "save" the frame are often, I think, risking greater damage to the frame when that heavier spring SLAMS the slide forward -- to be stopped by the slide stop -- and I've often warned to that possible outcome. (This is for springs used with hotter loads, because they think hotter loads demand it...)

I also have long felt that recoil buffers used in any handgun are a serious waste of money.

 

Folks who use heavier springs, on principle, to "save" the frame are often, I think, risking greater damage to the frame when that heavier spring SLAMS the slide forward.

Yep. They don't seem to understand that all that momentum is stopped by the lower lug feet hitting half the radius of the slidestop pin...which in turn transfers the impact to the slidestop crosspin holes in the frame. I've seen LW Commander frames crack vertically in the bottom of those holes from 20 and 22-pound springs.

. (This is for springs used with hotter loads, because they think hotter loads demand it...)

More times than I can remember, I've heard the advice to use heavier springs for +P ammo in order to contain the pressure, and I'm only mildly successful at convincing them that the spring doesn't have anything to do with that. I've literally had to fire a pistol without the spring in order to convince a few of'em...and even that didn't work a few times. Once, I was accused of having a "specially tuned pistol" just for that purpose.

 

This is helpful. So essentially we have two situations, using rough numbers and an overly simplified momentum calculation:

Standard slide 16 ozs standard spring 16 lbs = 16 x 16 or momentum of 256
Commander slide 14ozs, commander spring X lbs = 256/14 = 18 lbs spring to get same forward momentum to reliably extract and chamber the cartridge.

Am I following what you and Tuner are getting at?

You're spot on for the most part but the extraction is better for the standard due to more energy stored in the slide, the Commander's spring lessen's the energy available for extraction/ejection but the higher spring rate stores the energy to drive the lighter slide back to battery.

 

I was more focused on the destructive power being a result of momentum comment

Just saw this. No need to take it to another thread. It's related.

Keep in mind that low mass decelerates at a faster rate than a high mass whenever they encounter an equal outside force.

A light bullet moving at hyper velocity strikes with such force that it literally disintegrates. Witness a .220 Swift's performance on a groundhog at 100 yards.
This is partly due to bullet construction, but it's mostly due to the high impact velocities that cause the bullet to blow up. If that same bullet impacts at 600 yards, the results aren't nearly as dramatic, and the bullet penetrates deeper. Simplified...the harder the bullet hits an object, the harder the object hits back, as per Newton 3. Damage tends to be superficial. The 150 mph Ferarri will knock chunks off the bridge abutment, but doesn't disturb its structural integrity overmuch.

When high mass impacts, its momentum tends to drive it through the object because the object doesn't hit back as violently. The momentum is more efficiently conserved than with low mass, regardless of impact velocity. The loaded semi doesn't hit the abutment as violently, but it does more deep, structural damage due to its sheer mass and more efficiently conserved momentum.

The old-timers used to say that the heavier bullets "carried" better. Without realizing it, they were describing the more efficient conservation of momentum while encountering an outside force...the air.

Since the slide hitting the frame is literally and essentially a straight-line crash...the higher mass stands a better chance of doing deep, structural damage to the impact abutments than the lower mass...and since the lower mass Commander slide can have no more momentum than the bullet...and because the short barrel imparts less velocity and momentum to the bullet...the faster, lighter Commander slide carries less damage potential than the 5-inch slide...even with equal spring rates.

How much less is a matter of doing the math, but I suspect that there won't be enough difference to argue over...and that's the whole point. The notion that the faster Commander slide "needs" more spring to keep from beating the frame into a paperweight is not only wrong...it's absurd.

BECAUSE....

The slide's momentum can be no greater than the bullet's.

If the 5-inch gun can withstand tens of thousands of rounds with a 14 or 16-pound spring...so can the Commander or the Officer's Model. In fact, I've run Commanders and Combat Commanders with 16 pound springs for years...and many thousands of rounds...and there hasn't been a single problem.

 

Yep. They don't seem to understand that all that momentum is stopped by the lower lug feet hitting half the radius of the slidestop pin...which in turn transfers the impact to the slidestop crosspin holes in the frame. I've seen LW Commander frames crack vertically in the bottom of those holes from 20 and 22-pound springs.

Have seen lots of this...most frequently in 10mm 1911s...especially if the lower lug feet were sloppily fit. Have even seen holes stretch as opposed to cracking. Early sign is the link pin falling out. So what is the solution in a standard sized 10mm if the recoil spring shouldn't be used for higher power loads in the same sized weapon?

Just saw this. No need to take it to another thread. It's related.

Keep in mind that low mass decelerates at a faster rate than a high mass whenever they encounter an equal outside force.

A light bullet moving at hyper velocity strikes with such force that it literally disintegrates. Witness a .220 Swift's performance on a groundhog at 100 yards.
This is partly due to bullet construction, but it's mostly due to the high impact velocities that cause the bullet to blow up. If that same bullet impacts at 600 yards, the results aren't nearly as dramatic, and the bullet penetrates deeper. Simplified...the harder the bullet hits an object, the harder the object hits back, as per Newton 3. Damage tends to be superficial. The 150 mph Ferarri will knock chunks off the bridge abutment, but doesn't disturb its structural integrity overmuch.

When high mass impacts, its momentum tends to drive it through the object because the object doesn't hit back as violently. The momentum is more efficiently conserved than with low mass, regardless of impact velocity. The loaded semi doesn't hit the abutment as violently, but it does more deep, structural damage due to its sheer mass and more efficiently conserved momentum.

The old-timers used to say that the heavier bullets "carried" better. Without realizing it, they were describing the more efficient conservation of momentum while encountering an outside force...the air.

All of that makes sense and have read it in other places...so no dispute.

In the case of the .45 vs 5.56 though...what I am trying to quantify is given they have the same momentum...I still can't think of a situation where I would choose the .45 over the 5.56 if I were after destructive force. Even a higher momentum pistol round like the 10mm...beyond the science...I don't perceive it to be more destructive than a 5.56 over either weapon's effective range. Obviously the rifle round has much higher energy.

 

Early sign is the link pin falling out.

Link pin falling out is usually due to the barrel being stopped by the link instead of properly on the VIS..With the gun in battery, the link pin and its hole aren't under any stress unless some hack has long-linked the barrel to "increase the lockup." The other possibility is just a pin too small for a correct interference fit with the hole.

Slidestop pin hole elongation is one I've seen in steel frames. Aluminum alloy frames tend to crack.

With too much recoil spring, the lower lug feet become deformed. The early sign is the rear of the slide starts to sit further forward relative to the rear of the frame.

The solution is one that Ned Christiansen came up with. A top wrench who specializes in the Big Ten...he used a very small radius on the firing pin stop...a 25-pound mainspring...and an 18-pound Wolff recoil spring in a 5-inch pistol.

Although far too much is made of slide to frame impact damage, it's still something that has to be considered. The gun was designed around the .45 cartridge and the stresses imposed by it...not the 10mm. Modern steels are much better, but not that much.

With that in mind, he ran a series of tests and figured out that the reason Colt's team went with 22 pounds was to try and keep those impact forces more in line with hardball-level ammo. So, he started looking for other ways of reducing it. The firing pin stop radius and the added mainspring resistance was the only viable place to look because it has a delaying effect on the slide before it builds up a full head of steam...during the time that the greatest amount of force is being applied. It's also rumored that he prefers to use a full mass hammer to add a little more.

He installed a shock buff and fired the gun 500 times with full power ammo to establish a baseline. Then he made one change at a time, and compared the damage done to his baseline. When the buff's appearance closely matched the original...he stopped...and he actually said that there was a bit less damage to the buff with his system.

He'd solved the potential for frame abutment damage without the problems associated with overspringing the gun 50% and the gun is a lot more user-friendly to boot.

That firing pin stop radius isn't anything new. Back in the day before EGW started offering them with a square bottom, and I couldn't any of the pre-1918 originals in gun show vendors junk parts boxes...I went to the trouble to make my own...which actually worked better because I could put an even smaller radius on'em than the original 5/64ths that Browning used.

Bless George Smith's heart. He sure saved me a lotta work with his 12-dollar stop, and he made it oversized to boot, so we can fit it closely to the extractor and keep it dead vertical and stable in the channel.

 

In the case of the .45 vs 5.56 though...what I am trying to quantify is given they have the same momentum...I still can't think of a situation where I would choose the .45 over the 5.56 if I were after destructive force.

Ya might wanna rethink that. If you could feasibly bring the momentum of the 55-grain pill to equal the momentum of the heavy slug...and if you're 15 feet from a thoroughly pissed-off Black Rhino that's got you on screen...do you really wanna be standin' there with an AR15 between you and all that hurt?

At such impact velocities, you're still faced with the destructive forces imposed on the bullet. Just can't get around Newton 3, I'm afraid.

There are some very good reasons that the African professional hunters and guides prefer large, heavy bullets at moderate velocities. A guide will tell you that he doesn't care if you want to take after a Cape Buffalo with a slingshot if that's your preference...but he'll be carrying a heavy rifle and tough, solid bullets thankyouverymuch.

 

Ya might wanna rethink that. If you could feasibly bring the momentum of the 55-grain pill to equal the momentum of the heavy slug...and if you're 15 feet from a thoroughly pissed-off Black Rhino that's got you on screen...do you really wanna be standin' there with an AR15 between you and all that hurt?

At such impact velocities, you're still faced with the destructive forces imposed on the bullet. Just can't get around Newton 3, I'm afraid.

There are some very good reasons that the African professional hunters and guides prefer large, heavy bullets at moderate velocities. A guide will tell you that he doesn't care if you want to take after a Cape Buffalo with a slingshot if that's your preference...but he'll be carrying a heavy rifle and tough, solid bullets thankyouverymuch.

Barnes years ago made 120 grain .224 bullets that had the sectional density to easily outperform any .30 caliber 120 bullet; increase S/D, increase momentum.

 

Barnes years ago made 120 grain .224 bullets that had the sectional density to easily outperform any .30 caliber 120 bullet; increase S/D, increase momentum.

Well...Not exactly, Duster. If the mass and impact velocity are equal, there's equal momentum. No gettin' around that. Longer bullets penetrate deeper for two reasons. One is obvious. Less frontal area means less resistance in a given medium. Less frontal area means a slower rate of deceleration in the air, distances to the target assumed to be equal.

Higher impact velocity means more momentum at the instant of impact by virtue of Mass X Velocity. But at equal velocities...both bullets carry equal momentum.

The other is that there's more mass used in driving the bullet...more weight at the rear that keeps pushing as the nose starts to decelerate. The momentum is focused on a smaller area.

Two nails. One is wide, short, and blunt. One is long, skinny, and pointy. Assuming equal force from the hammer...which nail will penetrate deeper into the board?

Nothing means everything. Everything means something.

 

Ya might wanna rethink that. If you could feasibly bring the momentum of the 55-grain pill to equal the momentum of the heavy slug...and if you're 15 feet from a thoroughly pissed-off Black Rhino that's got you on screen...do you really wanna be standin' there with an AR15 between you and all that hurt?

At such impact velocities, you're still faced with the destructive forces imposed on the bullet. Just can't get around Newton 3, I'm afraid.

There are some very good reasons that the African professional hunters and guides prefer large, heavy bullets at moderate velocities. A guide will tell you that he doesn't care if you want to take after a Cape Buffalo with a slingshot if that's your preference...but he'll be carrying a heavy rifle and tough, solid bullets thankyouverymuch.

I think more of human animals and self defense when contemplating 5.56 and .45. Cape Buffalo's are beyond the scope of my analysis

 

Understood, Colt. You're still missing the point.

I never suggested that you go hunt Cape Buffalo with an AR15. The analogy was to explain the difference between high-speed/low mass and low-speed/high mass. It's never about just one thing. Nothing means everything. Everything means something.

But...

Even so, if you could drive a 60-grain .22 bullet to equal the momentum of the heavy bullet, you still can't get around Newton 3. The harder the bullet hits the target, the harder the target hits the bullet. It's not unilateral.

A light, low-mass bullet at the speed required may disintegrate before it reaches the vitals...even on a human being. It'd make a big, nasty-looking shallow wound, but if he's determined, he may not pay it much attention.

 

Well...Not exactly, Duster. If the mass and impact velocity are equal, there's equal momentum. No gettin' around that. Longer bullets penetrate deeper for two reasons. One is obvious. Less frontal area means less resistance in a given medium. Less frontal area means a slower rate of deceleration in the air, distances to the target assumed to be equal.

Higher impact velocity means more momentum at the instant of impact by virtue of Mass X Velocity. But at equal velocities...both bullets carry equal momentum.

The other is that there's more mass used in driving the bullet...more weight at the rear that keeps pushing as the nose starts to decelerate. The momentum is focused on a smaller area.

Two nails. One is wide, short, and blunt. One is long, skinny, and pointy. Assuming equal force from the hammer...which nail will penetrate deeper into the board?

Nothing means everything. Everything means something.

Given the same energy before contact to a large animal which of the above will penetrate and kill the animal. All other factors being equal where does momentum come to play?

 

All other factors being equal where does momentum come to play?

Penetration. Mass and momentum are the factors that determine how far the bullet travels in the medium as per Newton 1B/Conservation of Momentum. Momentum is the quality that keeps an object in motion when it encounters an outside force. Hence the M193/.45-70 Elk comparison.

Even with light/fast and heavy/slow equal momentums, and even if the light/fast bullet stays together...the penetration edge goes to the latter because the lower mass/faster bullet decelerates faster in a given medium. i.e The harder the bullet hits the target, the harder the target hits the bullet...as per Newton 3.

Newton 1B

"Objects in motion tend to remain in motion."

Newton 3:

"For every action, there must be an equal and opposite reaction."

 

Understood, Colt. You're still missing the point.

No, I am getting your point...it is clear and well reasoned.

 

Duster...Let's take it from a different perspective.

Two .38 caliber bullets, equal in every way except mass. One weighs a hundred grains and the other 200 grains.

At equal impact velocities, the 200-grain pill will theoretically penetrate twice as far. In reality, a little more than twice as far...because the low-mass doesn't conserve momentum as efficiently as high mass. (Known as ballistic coefficient)

Go double the impact velocity of the 100-grain bullet so it'll carry equal momentum. Theoretically, it should penetrate the same distance as the 200-grain slug...but in reality, it won't...because low mass decelerates faster in a given medium. Or, another way..."The harder the bullet hits the target (energy) the harder the target hits the bullet" and the faster the medium robs the bullet of momentum.

Take Nosler's excellent Ballistic Tip .30 caliber bullets. 150 and a 165-grains. Geometrically identical in every way except mass due to greater length. The 165 has a higher ballistic coefficient. It conserves momentum more efficiently, and at equal velocities, it will travel farther in the air....an outside force...in a straight line than the 150. Both will hit the ground at the same time, but the more massive 165 will be a little further down the road because it retains a greater percentage of its velocity because it conserves momentum more efficiently.

Clear as mud?

 

Duster...Let's take it from a different perspective.

Two .38 caliber bullets, equal in every way except mass. One weighs a hundred grains and the other 200 grains.

At equal impact velocities, the 200-grain pill will theoretically penetrate twice as far. In reality, a little more than twice as far...because the low-mass doesn't conserve momentum as efficiently as high mass. (Known as ballistic coefficient)

Go double the impact velocity of the 100-grain bullet so it'll carry equal momentum. Theoretically, it should penetrate the same distance as the 200-grain slug...but in reality, it won't...because low mass decelerates faster in a given medium. Or, another way..."The harder the bullet hits the target (energy) the harder the target hits the bullet" and the faster the medium robs the bullet of momentum.

Take Nosler's excellent Ballistic Tip .30 caliber bullets. 150 and a 165-grains. Geometrically identical in every way except mass due to greater length. The 165 has a higher ballistic coefficient. It conserves momentum more efficiently, and at equal velocities, it will travel farther in the air....an outside force...in a straight line than the 150. Both will hit the ground at the same time, but the more massive 165 will be a little further down the road because it retains a greater percentage of its velocity because it conserves momentum more efficiently.

Clear as mud?

No problem there but let's go back to what was stated about firing without a recoil spring and discuss the differences between a Standard and a Commander slide, would the slide velocity be the same when a common round is fired?