[JohnVF]

Is it true that a heavier bullet (180gr FMJ .40SW) has less recoil than a lighter bullet (165gr FMJ .40SW) fired from a 5" barrel? I would like to know which one would be better for competition.

Thanks.

[Dave R]

I think it would be the other way around. Heavier bullet=more recoil.

[dk-corriveau]

It would depend largely, but not entirely, on the momentum (mass*velocity)of each bullet as it left the gun. Not knowing the exit velocities for these I can't say one way or the other.

[Standing Wolf]

If two bullets are moving at the exact same speed, the heavier will generally produce more felt recoil.

That's a mighty big "if" at the start of the preceding sentence, since in most rounds, the lighter bullet tends to step out faster than the heavier. For competitive purposes, it's definitely worth your while to do two things: 1.) load your own, and 2.) experiment with various bullet weights, powders, and charges until you find the best combination of accuracy and recoil. Load development generally takes awhile; if you're at all serious about competing in any shooting discipline, however, the effort pays off handsomely.

[XLMiguel]

Well, basic physics (velocity = force X mass)) would suggest that getting two projectiles of different mass to the same velocity, the heavier one would require more force (energy) than the lighter one, and since for every action, there is and equal and opposite reaciton, then obviously, the heavier projectile would yeild more recoil (opposite reaction), all other things being equal (i.e. fired fromthe same gun).

Intuitively obvious to the meanest intelligence, eh?

[Starter52]

The other posts are correct. At the same velocity, the heavier bullet will have more recoil than the lighter bullet.

I'm sure this is correct; but Isaac Newton is really the guy to talk to :D

[zahc]

Well, basic physics (velocity = force X mass)

Care to derive that for me?:)

[RyanM]

Greater momentum means greater final recoil velocity. Velocities from a 4" barrel are something like 165 gr at 1150 fps or 180 gr at 1015 fps. In that case, the 165 gr bullet actually has more momentum. At 1107 fps, the 165 gr bullet would have the same momentum.

Final recoil velocity is not the only mechanism to recoil, though. There's also recoil acceleration, which is based on the bullet's acceleration. As a general rule, the faster the muzzle velocity, the greater the acceleration on both the gun and the bullet, so faster rounds have a snappier recoil.

I'd say go with 180 grain bullets if using full power loads. Less recoil velocity, less recoil acceleration, and greater terminal effect.

[HSMITH]

True recoil force doesn't really matter. FELT recoil is what we know and try to quantify. Generally heavier bullets feel softer than light bullets, overall recoil may or may not actually be higher than light bullets but it is generally spread over a longer period of time making it feel softer. Recoil velocity is the reason that they feel different.

Feel is all that really and truely matters in recoil comparisons. Most handloaders that experiment know this to be true. I can load several variations with the exact same bullet at the exact same speed and percieve drastically different recoil levels. True recoil force numbers are very very close, but the feel is definately different.

[JohnMc]

Given the same gun, the recoil is the reaction for the sum total of the momenta of the bullet, the burnt and still burning powder flying out the end, and the expanding gases.
Depending on the cartridge, a larger bullet may force the use of less powder or slower burning powders, etc, so sometimes a larger bullet can have less recoil in a given cartridge platform.

[Hypnogator]

Given the same gun, the recoil is the reaction for the sum total of the momenta of the bullet, the burnt and still burning powder flying out the end, and the expanding gases.
Expanding on John's answer, a bullet accelerated to a given velocity by a large charge of slow-burning powder will produce more recoil than an identical bullet accelerated to the same velocity by a light charge of fast-burning powder. Don't know if the difference would be perceivable by the shooter, though.

[JohnVF]

Thank you all......:)

I think I would go for the heavier bullet...... I noticed this in my .45 1911 using 200gr FMJ and a 230gr FMJ. The 230 felt softer than the 200. I'm just not familiar w/ .40, my first time to own one.

[blackrazor]

Recoil energy ("felt recoil") is proportional to the square of the velocity of the bullet times the sqaure of the mass of the bullet+powder. It is also inversely proportional to the mass of the gun.

[1911Tuner]

Recoil simplified:

Recoil occurs because the bullet is in the barrel and because it moves. Once the bullet exits, recoil is over, and the only movement of the gun after that point is all momentum. Therefore, the slower, heavier bullet will effect the recoil for a longer period of time, and...conversely...the lighter, faster bullet for a shorter time. The light, fast bullet's effect is more of a quick, sharp slap, while the slower, heavier bullet provides more of a push that's spread out over a longer distance and time period. The light screamer hurts more, while the slow heavyweight will move the shooter farther.

A perfect illustration came to me when I had the opportunity to fire a
Westley Richards double rifle in .600 Nitro caliber within a day of firing a .460 Weatherby. The sporter-weight .460 hurt my shoulder, but didn't force me to step backward. The much heavier .600 rifle nearly put me on the ground, and only by taking 2 steps back did I manage to stay up...and I was braced with my right foot well behind the left. Note that I'm no Sumo wrestler, but I'm not exactly a lightweight either at 6'2" and 200 pounds.

Not being convinced, I shot the .600 twice...mainly because I didn't want to shoot it three times.:p If that Westley Richards had been the same weight as the Weatherby, I'd have hit the ground like Jess Williard did when Dempsey caught him with that first left hook.

[solareclipse]

The .40 never feels right at first. Then you get used to it.. I would say it is more of a bullet issue than weight.

[bogie]

Keep in mind that .45 shooters looking to make major with 155 grain bullets load 'em HOT. And they claim that the additional powder actually _helps_ their muzzle breaks.

[Drewtam]

I'm new to firearms but consider myself well versed in physics, so please if I make a stupid firearm statement, be considerate in correcting me.

First some basic equations you should all know:

force = mass x acceleration
velocity = acceleration x time (unless you know calc, then its different):cool:
momentum = mass x velocity

NOW THE IMPORTANT ONE:

Impulse:
Impulse is the change in momentum, or in the firearm case the transfer of momentum from the fire to the arm. :p

http://www.regentsprep.org/Regents/physics/phys01/impulse/default.htm
Imagine the car to be the rifle or handgun and the force to be your shoulder or arms.


http://id.mind.net/~zona/mstm/physics/mechanics/momentum/introductoryProblems/momentumSummary2.html
http://hyperphysics.phy-astr.gsu.edu/hbase/impcal.html
(calculator)

Impulse is going to be the measure of recoil. But impulse is not what you 'feel', force is what you feel. So for the same impulse, lowering the force and increasing the time it acts will decrease the feel. So a system like a pad increases the time that the rifle recoils, but lowers the force acting on the rifle and you because it is soft. Or a system where the recoil of the weapon is controlled by hydraulics and dampers will allow the gun to "slow down" (read force) over a longer time.

Is it clear as mud now?
Drew