.40 production

[ATLDave]

Yep.  Momentum is what knocks things over, but not all collisions are elastic.  In fact, outside of a HS physics class, no collisions are perfectly elastic.  And splattering lead (along with generating heat and making the steel vibrate/ring) are all places the energy can get spent other than pushing the steel back/down.  

[IHAVEGAS]

Show me the test data  . 

You can theorize that 9mm has the higher kinetic energy (energy = 0.5 x velocity x velocity) or that slower heavier bullets transfer energy better to steel or that bullet shape effects friction/deformation and that effects energy transfer or that steel poppers behave the same as wooden bowling pins or that bullet hardness determines  richochet versus energy transfer, or all of the above and more. 

When somebody does some real tests then we will know. 

[sbo76]

On 08/08/2016 at 9:19 AM, aandabooks said:

I'm picking up a G35 and plan to use it both as a backup gun for my son's G34 and my XDm in Production. It will also serve as a backup to my 2011 in Limited.

I'm going to look at building some .40 minor loads using 200gr bullets moving at no more than 675 FPS. I figure if a 147gr making minor is considered soft shooting then a 200gr making the same PF is going to feel even softer with the same weight gun to shoot it out of.

jakemaul, technically .357sig is the smallest caliber to make major in Limited. The debate there would be velocity over bullet weights. .357sig is cheaper to load than .40 though.

By rule .40 is the smallest caliber for Ltd, Ltd 10, ss to make major pf.

 

[sbo76]

57 minutes ago, IHAVEGAS said:

Show me the test data  . 

You can theorize that 9mm has the higher kinetic energy (energy = 0.5 x velocity x velocity) or that slower heavier bullets transfer energy better to steel or that bullet shape effects friction/deformation and that effects energy transfer or that steel poppers behave the same as wooden bowling pins or that bullet hardness determines  richochet versus energy transfer, or all of the above and more. 

When somebody does some real tests then we will know. 

I don't have any lab testing but my 160g slow bullets knock down steel much more effectively than my 124 fast bullets both making pf of 130 (+-2).

[IHAVEGAS]

51 minutes ago, sbo76 said:

I don't have any lab testing but my 160g slow bullets knock down steel much more effectively than my 124 fast bullets both making pf of 130 (+-2).

If you ever got bored, it would be an interesting thing to test with a pepper popper and a shot timer.

Paint popper so hits can be verified. 

Shooter 1 - aim a careful shot at center of popper.

Shooter 2 - fire a time marker shot when you see the popper hit the ground.

Review the time between shots. 

Not a perfect test, someone may have a better idea, but if there is a worthwhile difference then it should be obvious. 

Your perception may well be correct, but sometimes when things are measured surprises are found and it would be interesting to know the real time in seconds difference either way. 

 

[ATLDave]

The slow motion video feature built into modern phones or action cams should be sufficient for comparing the speed/time of falling poppers.  No need to try to time a second shot or guess.  Just shoot it, film it, review the film in a program (like Shot Coach) with a time indicator/scale.  This is an eminently testable issue.  

[IHAVEGAS]

27 minutes ago, ATLDave said:

The slow motion video feature built into modern phones or action cams should be sufficient for comparing the speed/time of falling poppers.  No need to try to time a second shot or guess.  Just shoot it, film it, review the film in a program (like Shot Coach) with a time indicator/scale.  This is an eminently testable issue.  

That works.

Other thought that came to mind was elevation. If bullet x transfers energy better it should drop the popper with a hit farther below the center of the calibration zone. 

[IronArcher]

At the same power factor, the slower/heavier bullet will normally have more KE and momentum.



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[ATLDave]

On 11/5/2016 at 5:54 PM, IronArcher said:

At the same power factor, the slower/heavier bullet will normally have more KE and momentum.

 

That's objectively, indisputably wrong.  "F" in physics class wrong.  

[IHAVEGAS]

On 11/5/2016 at 4:54 PM, IronArcher said:

At the same power factor, the slower/heavier bullet will normally have more KE and momentum.



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Kinetic Energy = 1/2 * Mass * Velocity Squared

Momentum = Mass * Velocity = Power Factor = Constant regardless of bullet weight if power factor is the same

So, kinetic energy favors the lighter and faster bullet.

If we want to go all nerdy on it. 

How effectively the energy is transferred is the interesting part. 

[davsco]

36 minutes ago, IHAVEGAS said:

Kinetic Energy = 1/2 * Mass * Velocity Squared

Momentum = Mass * Velocity = Power Factor = Constant regardless of bullet weight if power factor is the same

So, kinetic energy favors the lighter and faster bullet.

yep the velocity is squared and the mass is halved in the kinetic energy equation.

the time for poppers to fall seems like a neat experiment, hope someone does that, or maybe someone already has.

however, the reaction we want on poppers (quicker, more vicious fall) is generally the opposite reaction we want in our gun (ie we want less and not more recoil on the gun).

[GrumpyOne]

2 minutes ago, davsco said:

yep the velocity is squared and the mass is halved in the kinetic energy equation.

the time for poppers to fall seems like a neat experiment, hope someone does that, or maybe someone already has.

however, the reaction we want on poppers (quicker, more vicious fall) is generally the opposite reaction we want in our gun (ie we want less and not more recoil on the gun).

How do you get a "quicker, more vicious fall" on a forward falling popper?

[IHAVEGAS]

1 hour ago, GrumpyOne said:

How do you get a "quicker, more vicious fall" on a forward falling popper?

Forward falling poppers are stupid. 

[motosapiens]

14 minutes ago, IHAVEGAS said:

Forward falling poppers are stupid. 

unless you have parts of your range where rounds skipping over the berm are a problem.

[IronArcher]

On 11/7/2016 at 8:47 AM, ATLDave said:

That's objectively, indisputably wrong.  "F" in physics class wrong.  

Actually, you are correct, I mis stated what I meant.

With the same power load (not factor), the heavier bullet will be slower, but will theoretically have more KE and momentum.

[ATLDave]

I don't know what "same power load" means.  I know what power factor is.  It's a momentum calculation.  PF IS momentum.  

I know what kinetic energy is.  For two objects with the same momentum, the lighter, faster one will ALWAYS have higher kinetic energy.  Because math.

I don't know what "power load" is, though.  

[Onepocket]

After listening to all the physics majors on here I have come to the simple conclusion that 9mm runs more reliable than .40.  

[IHAVEGAS]

2 hours ago, ATLDave said:

I don't know what "power load" is, 

I think it has something to do with why I had to quit eating cheese sandwiches . 

[ATLDave]

[IronArcher]

I don't know what "same power load" means.  I know what power factor is.  It's a momentum calculation.  PF IS momentum.  

I know what kinetic energy is.  For two objects with the same momentum, the lighter, faster one will ALWAYS have higher kinetic energy.  Because math.

I don't know what "power load" is, though.  

The heavier bullet object, with the same amount of force pushing it, will "absorb" more energy.
For the topic at hand, it will also retain a larger amount of that energy downrange.


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[Slow250]

On 11/11/2016 at 4:29 PM, Onepocket said:

After listening to all the physics majors on here I have come to the simple conclusion that 9mm runs more reliable than .40.  

Probably depends on the platform. 

[hitman]

Think he meant velocity not power load.

To get back on track.

I suspect cost is the primary.

I shot 40 minor in production and while the bigger hole was nice at times it felt like the slide was slower (even with a lighter spring).

Time was a little better with my 9 vs 40.

[FWSixgunner]

I think it has something to do with why I had to quit eating cheese sandwiches . 

So, your username isn't just hot air?