David M wrote:We know that the momentums are the same but I think the key to the felt bit of
this is the powder charge.
To launch a lighter projectile faster in the same barrel length we need to accelerate
a lot faster and thus a lot more powder.
Typically you may need up to a grain more of the same powder.
Recoil is the reaction of both the projectile and the powder weight, and somewhere in all
this must come muzzle blast as the projectile exists the barrel.
Also if we change the powder burn rate we change both peak pressures and acceleration
rates as well as charge weight.
I think the key would be acceleration, not the powder weight. Although muzzle blast might make it seem different.
I guess 'someone' needs to run the tests to give us the results similar to a temperature/humidity comfort factor.
To me it depends what your shooting. If your shooting a comp gun than the 130 gr 38 super with a presure almost twice that of the 45 works the best. It keeps muzzle flip down and the recoil is more stright back. Stock gun a lot of people were going with a 40, it is easier to make major power factor than the 38 and less torque than the 45. In the long run it doesn't realy matter in the hands of someone who knows how to shoot. Kind of like the fancy golf club.
Felt recoil is actually a very personal experience, no matter what the math might suggest. I'm mostly a rifle shooter and always have been, but I did do a fair bit of pistol shooting when it was legal over here. I never shot IPSC so did not ever worry about making Major PF. I used to shoot Service Pistol with an RAF issue Browning Hi Power. I never liked the way that the 9mm with service issue ammo felt in the hand. I found that the impulse seemed to sting the palms of the hand for some reason. I never shot much .45ACP, and when I did it was in a 1917 vintage Military issue pistol that was as loose as anything. I did notice a lot more torque pulling the pistol round, although the thing seemed to be wobbling around for ages compared to a 9mm. Handgun wise I most shot my 6" S&W 586 usually in Police Pistol 1 courses of fire, but also the occasional ISSF Centerfire match. Either way I used to mostly use a really light .38spl match handload. This was a 148 gr HBWC at around 850 fps. This gave almost no felt recoil at all, although I would still not want to get in the way of it. It was also really really accurate. Shooting wise I could pretty much hit the middle all the time, with the autos I would be lucky to keep the rounds on a full size Fig 11 target at 20m. Mind you a 586 also benefits from much better sights than either the issue Hi Power or the 1911.
It appears than the lighter bullet has to go faster, thus be accelerated harder with more
powder and with less barrel time than the heavy bullet.
This extra powder and higher velocity combine to give a higher recoil impulse than the
heavier bullet but over a reduced locktime.
Lighter bullets then have a "sharper, snappier" feel than the slower "push" of the heavier
bullet.
The least recoil will be the heaviest bullet with the type of powder that gives the velocity
with the smallest charge wt.
The most accurate and best feel.....well keep trying different loads.
The least recoil will be the heaviest bullet with the type of powder that gives the velocity
with the smallest charge wt.
I don't agree with this part, the powder charge is barely relevant compared with the bullet weight. A small charge would require a fast powder.
If a slow heavy bullet is best then I would think a slow powder would also reduce the 'snappiness' of the recoil.
The least recoil will be the heaviest bullet with the type of powder that gives the velocity
with the smallest charge wt.
I don't agree with this part, the powder charge is barely relevant compared with the bullet weight. A small charge would require a fast powder.
If a slow heavy bullet is best then I would think a slow powder would also reduce the 'snappiness' of the recoil.
My favourite 9mm load: 145gr projectile with ADI AP100 powder (heavy bullet, slow powder).
I said when I started this topic that it was not a simple topic.
When you look closely at high speed video of a shot being fired
you will see that most of the recoil movement happens in various
stages, mostly after the bullet has left the barrel.
The initial movement as the bullet exists, fairly slight.
A lot more movement as the gas impulse takes over, and then
with the auto a big movement as the slide hits the end of its travel.
I think that powder charge/speed of burn although only a small weight
compared to the bullet mass has a greater effect on recoil with its gas
impulse than we give it credit.
It occurred to me that in a simple blowback design such as most .22 pistols it could be more complicated.
In a an extreme case the bullet might not leave the barrel at all, but the slide would still be propelled backwards, strike the slidestop and create felt recoil.
I have a batch of .22 ammo which clearly gives more felt recoil, and a louder bang, but the velocity chronographs lower than other types.
I suspect the bullet diameter is slightly greater, causing more force on entering the rifling and more friction down the barrel.
This wouldn't apply to delayed blowback firearms or revolvers.
