Maverick223
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I disagree; IMO the .45ACP is noticeably louder and is unquestionably less snappy with two similar pistols (but as is typical, built on different frames).
Physics behind "Push" vs "Snap"
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The thing about slide velocity (for autoloading pistols) is that it's dependent only on recoil (momentum) and the mass of the slide itself. This would seem to imply that two loads of two different calibers that happen to have the same recoil impulse (based on bullet momentum) would cause the slide to move at the same velocity, and that the recoil would therefore feel the same in similar weapons (of similar mass). The physical reality is a bit more complex since the slide is coupled to the frame through the recoil spring, but unless somebody can show how this or other factors that have not yet been covered here could result in a noticeable difference in the recoil force curve, there theoretically should not be an inherently qualitative difference between the "push" of .45 ACP and the "snap" of .40 S&W--they should feel pretty much the same.
By the way, while I have to say that I've felt such a difference when shooting these two calibers back-to-back, as is common these days the .45 ACP pistol was significantly heavier, so that doesn't count--the pistols have to be of similar weight for the comparison to be fair.
Just for further mental gymnastics, think about identical handguns pointed at each other with the barrel tips touching. Assume that we are able to fire a bullet from one gun cleanly into the barrel of the other gun.
Is recoil the same or different for the 2 guns?
Is recoil the same or different for the 2 guns?
Maverick223
Member
Different. The second gun (the one "catching the bullet") doesn't have the additional recoil from the powder charge, nor is all of the energy transmitted (due to a small amount of loss).
Ohio Gun Guy
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Maverick223
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If the velocity and bullet weight is the same (which isn't typical) then the recoil should be as well (assuming the same amount of powder consumed); in other words, I don't believe the burn rate is important. The recoil due to powder mass is dwarfed by that of the projectile mass and therefore of little significance to begin with. I certainly can't tell a difference when a different powder is used to produce similar performance (though it is usually a similar powder weight to attain such performance). That said, I only handload for rifle cartridges, pistol may be a bit different.
Deanimator
Member
It's just a matter of time/pressure curve.
The more pressure over a shorter period of time, the sharper the recoil impulse.
The more pressure over a shorter period of time, the sharper the recoil impulse.
Deanimator
Member
I'm betting you mostly stick to powders of roughly the same speed, like 4895, 4064, etc. 4895 and 4350 definitely feel different in a .30-06. 4350 is a MUCH slower powder, slow enough to bend the op rod of a Garand.
Maverick223
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For the most part I do stick to powders with similar properties (especially in the higher recoil cartridges, like .375H&H and .45-70Govt., where you might be able to discern a smaller difference). I still doubt that there is a great deal of difference if you are able to achieve similar ballistics.
MacTech
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I'm wondering how much case volume has to do with this as well, I may just test a theory this weekend, I'll load up some .45 ACP cartridges with a maximum load of Unique or W231, and put that same powder volume in a .45 Colt case as well, try each round in my Ruger New Model Blackhawk .45 Convertible, that should minimize variables, the only difference between the two configs will be the insignificant weight difference between the .45 ACP and .45 Colt cylinders
My guess is that the Colt loads will have less felt recoil as there's more expansion room and that should keep the internal pressure low
same primers, powder and bullet (200 Gn LSWC), the only variable will be the size and volume of the cartridge case
My guess is that the Colt loads will have less felt recoil as there's more expansion room and that should keep the internal pressure low
same primers, powder and bullet (200 Gn LSWC), the only variable will be the size and volume of the cartridge case
I don't own an autoloader, but I have shot a few over the years. You're talking about comparing perceived recoil. Can't you change the felt recoil by simply changing the recoil spring, and thus changing the amount of time over which the recoil force is exerted?
MacTech - with the same components in a 45 ACP and a 45 Colt, the Colt will presumably have a much lower velocity. Less pressure, less velocity, less recoil.
MacTech - with the same components in a 45 ACP and a 45 Colt, the Colt will presumably have a much lower velocity. Less pressure, less velocity, less recoil.
BeerSleeper
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It depends on how you quantify recoil. In terms of energy, nearly the same. The differences would be do to the firing pistol also "feeling" the recoil of the burned powder ejecta, and the more gradual acceleration of the bullet. The firing pistol is recoiling from the acceleration of the bullet over the length of the barrel (say 4"). The "catching" pistol will "feel" essentially no recoil until the bullet hits the end of the barrel, in which moment it will essentially instantaneously absorb the full energy of the bullet in a much shorter period of time than the firing pistol (again, nearly instantaneously). If one could feel the recoil of each pistol, I imagine one would compare the firing pistol as more of a "push" type feel, and the catching one as more of a "snap" type feel.btg3 said:
Maverick223
Member
I agree, add enough additional powder to keep the velocity the same and the .45LC should have more recoil.
While the recoil impulse (total energy) may be the same, there is obviously a difference between the duration of the impulses.
We detect that as a push vs. a blow (as in sharp strike).
It shows up in odd places, and different ways.
Impact loading is a very different thing depending on the strength (area) of the impluse and how quickly it is delivered.
If you pushed gently on an object for 10 minutes you might barely damage it.
Deliver the same impulse using a hammer and you may have a different outcome.
We detect that as a push vs. a blow (as in sharp strike).
It shows up in odd places, and different ways.
Impact loading is a very different thing depending on the strength (area) of the impluse and how quickly it is delivered.
If you pushed gently on an object for 10 minutes you might barely damage it.
Deliver the same impulse using a hammer and you may have a different outcome.
Among all the variables involved the greatest variable is perhaps perception, and what one expects to experience. You can load dissimilar cartridges with identical powder loads and the same weight bullets to eliminate as many variables as possible but still feel push vs snap based upon expectations. So to eliminate this the test would need to be a blind one, where the shooter doesn't know which caliber he is shooting. If there is still a definite difference, then I'd expect it to be a difference in volume on the cartridge producing different pressures, and/or the respective volumes of the barrels producing differing rates of gasses filling the void.
I still maintain that the sound of the discharge can greatly influence a person's perception of recoil. Take for instance that the flinch is a (p)reaction based solely upon expectation, and is as much a result of noise as it is of recoil.
I still maintain that the sound of the discharge can greatly influence a person's perception of recoil. Take for instance that the flinch is a (p)reaction based solely upon expectation, and is as much a result of noise as it is of recoil.
Deanimator
Member
You're still not allowing for the amount of time in which a given pressure is generated.
There's a big difference between Unique and Bullseye. The former is far more likely to give you a push than a smack.
Combustion velocity makes a BIG difference, both in explosives and propellants. It's the difference between blasting agent and PETN. People don't cut rails with blasting agent and they don't move earth with detonating cord.
Maverick223
Member
I'm still not entirely convinced that there is a significant difference, but like I mentioned earlier I don't handload for pistol cartridges, yet (I plan to start loading 9mmPara. and/or .45ACP when I purchase a pistol caliber carbine), so I may be incorrect.
I keep hearing people discount the mass and velocity (pressure) of the gasses coming out of the end of the gun. If you ever shoot a suppressed weapon with and without the suppressor on, using the same ammo, you will notice a significant reduction in recoil that is not a subjective expectation (suppressor work mainly by retarding the gases released from the muzzle). Even a +p 45ACP operates at a lower pressure than the 40S&W.
BeerSleeper
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That is likely due more to the weight of the suppressor hanging off the end of the barrel. It adds mass to the gun. Also, that mass is added further out from the guns center of mass, thereby increasing moment of intertia, which reduces recoil induced muzzle flip.
in a typical 9mm loading, the bullet has a mass of 124 grains, while the powder charge is in the 6-7 grain range. In this case, the mass of the gasses account for 5% of the total projectile. Not substantial, but also not insignificant.
in a typical 9mm loading, the bullet has a mass of 124 grains, while the powder charge is in the 6-7 grain range. In this case, the mass of the gasses account for 5% of the total projectile. Not substantial, but also not insignificant.
Maverick223
Member
No, a sound moderator often affords greater recoil reduction than a good brake up to .338LM (whereas larger cartridges have proven to work best with a brake). This is not due to added weight (because the reduction is far greater than that what can be attributed to the weight alone), but rather due to redirecting gases back to the shooter (much like a muzzle brake, though obviously in a slightly different manner resulting in sound reduction rather than an increase in perceived noise).
SSN Vet
Member
one word answer.... Impulse
Unfortunately, adjectives fall short when attempting to communicate very specific physics concepts and mathematics is required.....
Impulse is the integral of a force with respect to time.
A small force applied for a long time can produce the same momentum change as a large force applied briefly. But you will observe a different sensation.
What's really amazing is that our physical senses can distinguish between similar events that vary on the scale of miliseconds.
Unfortunately, adjectives fall short when attempting to communicate very specific physics concepts and mathematics is required.....
Impulse is the integral of a force with respect to time.
A small force applied for a long time can produce the same momentum change as a large force applied briefly. But you will observe a different sensation.
What's really amazing is that our physical senses can distinguish between similar events that vary on the scale of miliseconds.
o Unforgiven o
Member
No, there is such thing as "inherently more accurate", it all comes down to consistency.
So if rifle XX had 1 inch of muzzle rise and rifle YY had 5 inches of muzzle rise, assuming perfect consistency by the shooter and all other variables equal they would both be just as accurate.
Of course, what I just said is not in fact accuracy but precision which warrants another thread all to itself.
(I only jest, there are enough of those threads already)
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