.40 loaded to same as .45 acp = same power?

[Pumpkin]

If the 40 S&W is “Short and Week” what is the 9mm?
Shorter and for the Weekend?

[44 AMP]

The 9mm is for war!
Parabellum!!

or, at least in the opinion of Georg Luger and many other Europeans...

[JMag1]

Originally Posted by 44 AMP

The 9mm is for war!
Parabellum!!

or, at least in the opinion of Georg Luger and many other Europeans...

But, what for when one wants to win one, or two?

[Aguila Blanca]

Originally Posted by JMag1

But, what for when one wants to win one, or two?

Well, :duh:

.45 ACP, of course. In an M1911A1 -- it was good enough for John Wayne to win WW2 single-handed.

[rc]

200 grain bullets are not recommended for the 40 because of the taper inside the case. You may get rounds that can't chamber and you may be more likely to spike pressures due to limited case capacity. I would just load the 180s in 40 to the same speeds as 180s in a 45 if you want to match power. 40s operate at a much higher pressure as well. Something like 17000psi vs 33000psi.

[Pumpkin]

And why push it, what is a 200gr .40 cal going to do that a 180 won’t do, especially considering the extra velocity.

[74A95]

Some people don't seem to understand the point of the question.

[Pumpkin]

Oh I think we understand, Is it Six or Half a Dozen?

[Shadow9mm]

Give the same bullet weight and velocity they would have the sane energy. Recoil might be slightly different due to the increased bearing surface of the 40cal bullet. And due to the oncreased sectional density the 40cal would penetrate better.

[74A95]

Originally Posted by Shadow9mm

Recoil might be slightly different due to the increased bearing surface of the 40cal bullet.

Does this mean the 40 would have more or less recoil than the 45?

And how does bearing surface contribute to recoil?

[Shadow9mm]

Originally Posted by 74A95

Does this mean the 40 would have more or less recoil than the 45?

And how does bearing surface contribute to recoil?

In theory, as i understand it, my thought process is this. increased bearing surface would mean increased friction, both in starting and while traveling down the barrel. Increased friction means you need a harder push, more energy, to get the bullet to the same velocity. More energy means more recoil. Would it be noticeable to the average shooter? Somehow i doubt it. But as i understand it, yes there would be more recoil.

However i made an oversight in assumingthe bearing surface area on the 40cal would be larger. While the 40 cal would most likely have a longer bearing surface, the over all area of the bearing surface could be the same or less than the 45 based on the reduced diameter of the 40cal bullet.

[HighValleyRanch]

Yes, I was going to bring that up, that the bearing surface would not necessarily be larger because although maybe a longer surface as to the bullet length, the circumference of the larger .45 would make the bearing surfaces pretty close in size.
Not a math wizard, so I didn't take the time to calculate this.

[74A95]

I found an article that compared recoil of same weight bullets (200 grain) in the 40 and 45. When using the same gunpowder, which is critical for a same-to-same comparison, it shows the 40 produced less recoil than the 45. The reason is the 40 requires less powder to push the 200 grain bullet to the same speed.

https://www.1911addicts.com/threads/...tridges.25116/

It's in post #2, click on "see more". Look for Table 5 and the figure just above it.

"The 200-grain bullets in .40 S&W produced 5.3% less movement than the same weight in the .45 ACP (pictured below)."

"Why does the same weight bullet produce different amounts of recoil in different calibers? Once again, a major player is the amount of gunpowder required to reach the same velocity. In this case, the larger caliber required more gunpowder to reach the same velocity."


Also, a similar comparison was made between 38 Super and 45 Auto with the same weight bullets. The smaller diameter 38 Super required less of the same powder and therefore produced less recoil than the 45. Look for the "160 grain Accurate #7 No Compensator" figure.

https://www.shootingtimes.com/editor...sated-38/99515

[HighValleyRanch]

excellent, thanks for doing that research.
Wonder what powder they were using in post 2 for the 200 grain tests of the .45 and .40
That seemed like quite a difference in the amount of powder needed for each to push the same weight bullet.
But there you go. Smaller pistol, same recoil essentially, same power factor, and less powder in the .40 to .45 comparison.

[74A95]

In post #1 they say handloads were done with Ramshot Silhouette.

"Handloads
The limitation of comparing factory ammunition (unknown gunpowder) can be solved by using the same gunpowder in handloads. Ramshot Silhouette gunpowder was loaded with the same bullet weights as the factory ammunition (Table 3). Three different charge weights were loaded for each bullet to allow analysis for a specified velocity with linear regression. For this analysis, the Ransom Rest movement was calculated for the same velocities produced by the factory ammunition."

[44 AMP]

A whole 5.3%?? wow!

Doubt I could notice that without test equipment, doesn't sound like something I would seriously concern myself about, I think.

[JohnKSa]

Which is why the mass of the powder (while theoretically a factor in recoil) is usually ignored when calculating the recoil of pistol cartridges.

[Aguila Blanca]

Originally Posted by 44 AMP

A whole 5.3%?? wow!

Doubt I could notice that without test equipment, doesn't sound like something I would seriously concern myself about, I think.

I think that 5.3% is well within the range of experimental error. Consider that a Ransom Rest doesn't have any way of measuring movement, and the inserts that hold the gun are slightly soft. To measure movement requires setting up some sort of external Rube Goldberg apparatus to try to quantify how far up the gun flips in the Ransom rest. I doubt very much that three strings of five or seven shots each fired out of the same gun would register less than 5.3% difference.

[74A95]

Originally Posted by Aguila Blanca

I think that 5.3% is well within the range of experimental error. Consider that a Ransom Rest doesn't have any way of measuring movement, and the inserts that hold the gun are slightly soft. To measure movement requires setting up some sort of external Rube Goldberg apparatus to try to quantify how far up the gun flips in the Ransom rest. I doubt very much that three strings of five or seven shots each fired out of the same gun would register less than 5.3% difference.

Measuring movement with a RR looks pretty easy. Just measure how far the rocker arm/gun moves. A simple ruler works.

https://www.shootingtimes.com/editor...n-recoil/99442

I've lots of experience with a RR. The inserts hold the gun firmly in place, and it's not subject to moving back and forth when the gun fired then reset to the start position. The recoil always pushes the gun to the rear, and there is a special tab on the rocker arm to push the assembly back down to the start position, so there is no force applied to the gun to push the gun forward.

The article above shows some of the actual movement data, and it correlates extremely well with recorded velocity. It can distinguish between different gunpowders and different charge weight of the same gunpowder.

[74A95]

Originally Posted by JohnKSa

Which is why the mass of the powder (while theoretically a factor in recoil) is usually ignored when calculating the recoil of pistol cartridges.

According to who?

The difference in recoil between powders can be significant. In the article below they found a 20% difference in recoil between N320 and A#7. See table 1.

https://www.shootingtimes.com/editor...n-recoil/99442

[JohnKSa]

"Usually" isn't according to "someone", it's a statement about the ordinary.

If you think it's worthwhile , you can do a random survey of a significant number of references to handgun recoil and see how many of them talk about powder charge vs how many don't and see if my comment is correct or not.

[74A95]

.,,,

[MarkCO]

Originally Posted by JohnKSa

Which is why the mass of the powder (while theoretically a factor in recoil) is usually ignored when calculating the recoil of pistol cartridges.

It is only ignored by simpletons. Ballisticians, Engineers, and those who know, include the powder mass within the term "ejecta" which is the sum of the powder and bullet, wad (if used) in many formulas. Other times it is broken out as a separate variable. It is not "theoretically" a factor, it IS a factor. Just because non math types ignore it does not move it from an actual variable needed for accurate calculation to "theoretical". It was proven, thus, not theory, long before any of us were alive.

Power Factor is a grossly simplified version that is not even accurate. It is more for relative comparison and to aid in simple calcs for competition.

Even the simplified velocity formula includes it...

Vf = (Mb x Vb + Mc x Vc)/1000Mf

Vf is the firearm velocity and the other variables are Bullet Mass, Bullet Velocity, Mass of Charge, Velocity of charge respectively

[Jim Watson]

Coming up with a number for Vc is the trick.
I have seen various multiples of Vb and arbitrary numbers as high as 4500 fps.
Has a highly instrumented ballistics lab measured the "uncorked" gas jet to get a value?

Long ago I saw an item with a gun suspended on strings to form a ballistic pendulum, overall recoil was actually measured.

[Aguila Blanca]

Originally Posted by 74A95

Measuring movement with a RR looks pretty easy. Just measure how far the rocker arm/gun moves. A simple ruler works.

A simple ruler doesn't work, because a Ransom rest doesn't move in a linear direction -- it rotates. Sure, you can use a protractor of some sort mounted beside the Ransom rest, but that requires making a precise visual alignment with something that's not part of the actual Ransom rest. That's why I said that 5.3% is within the margin of error for however you are attempting to measure the movement.

I have had a Ransom rest for years. I feel absolutely certain that it's not possible to quantify the recoil movement to within 5% accuracy/precision.