Skeptical about px4 rotary barrel

[Vicissitude]

I'm no rocket scientist but I've taken college physics and based one my understanding of how handguns work recoil is caused by the slide spring bunching up and the slide hitting the end of its cycle. If this is true then how does a rotating barrel dissipate recoil if the barrel has nothing to do with rearward forces?

[nedro]

Mass.
Sheer Mass.
The MOI on a plastic gun is almost nil.
The MOI on an all steel revolver is substantial.
(MOI = Moment Of Inertia)

[Vicissitude]

I'm not sure how this applies to what I'm asking, what I think you Are saying is that kinetic energy is a function of mass so the higher the mass of the pistol the less rearward velocity(there's a fart joke in there somewhere) it will experience, which is why a full metal 1911 has less felt recoil than a block. Which makes sense.

[AK all day]

Recoil is the opposite and equal reaction of the bullet leaving the gun, which some of that energy is used to cycle the slide. I believe the theory is that due to the barrel moving on an axis and remaining perfectly horizontal, it has an effect on the amount of muzzle flip the gun has, not actually reducing the energy amount, but keeping the front of the gun down.

I myself feel this when comparing the gun side by side with others in the same weight catagory, in the effect that the gun shoots "smoother" than say, a Glock 19. But the effect is fairly insignificant IMO. Reliability wise, there is nothing wrong with a rotating barrel.

My $0.02

[Vicissitude]

Glock not block, **** autocorrect.

[aspenvalley]

How does the barrel have nothing to do with the rearward forces. It remains locked until the pressure drops in the barrel. The barrel and the slide are locked together while all the force is transfer to the slide. Once it starts to turn (tilt for that matter in a tilting barrel setup) the pressure has already dropped and the bullet has left the barrel.

[nedro]

I'm not sure how this applies to what I'm asking, what I think you Are saying is that kinetic energy is a function of mass so the higher the mass of the pistol the less rearward velocity(there's a fart joke in there somewhere) it will experience, which is why a full metal 1911 has less felt recoil than a block. Which makes sense.

Yes. It takes a larger force to move bigger objects from a stationary position.
I may not know exactly what you are asking, though.
Are you talking revolvers vs semi autos? If so, I think I have answered correctly.

EDIT:
Yep, I missed it. I was not answering your question.
Carry on.

[OCEquestrian]

Curious as I do not own one and have not fired one... does the rotary bolt in the PX4 rotate in the opposite direction as the twist of the rifling?

[aspenvalley]

Curious as I do not own one and have not fired one... does the rotary bolt in the PX4 rotate in the opposite direction as the twist of the rifling?

Not sure but the rifling is right hand twist, I don't have one so I have no idea which way the barrel twists...

[robert101]

I'm no physicist (my daughter is though) but the recoil has nothing to do with the rotating barrel. The recoil, as mentioned earlier, is due to the acceleration of the bullet. That force has to translate into the opposite direction. The force of the case is exerted on the breech face which is represented by a backward vector. The recoil feel maybe lessened by the weight of the gun. This is due to Newton's laws of physics - An object at rest tends to stay at rest.

[aspenvalley]

I'm no physicist (my daughter is though) but the recoil has nothing to do with the rotating barrel. The recoil, as mentioned earlier, is due to the acceleration of the bullet. That force has to translate into the opposite direction. The force of the case is exerted on the breech face which is represented by a backward vector. The recoil feel maybe lessened by the weight of the gun. This is due to Newton's laws of physics - An object at rest tends to stay at rest.

I think the idea-myth is that a rotating system takes more energy to operate than a tilting barrel. Also you have to possibility for a lower bore axis, as it does not need a link or a space to tilt down into. This would lead to less muzzle flip and less felt recoil.

If you want a softer shooting gun, in my opinion you have two options that really effect changes. Either less powerful round or a heavier gun (or both).

[OCEquestrian]

I think the idea-myth is that a rotating system takes more energy to operate than a tilting barrel. Also you have to possibility for a lower bore axis, as it does not need a link or a space to tilt down into. This would lead to less muzzle flip and less felt recoil.

If you want a softer shooting gun, in my opinion you have two options that really effect changes. Either less powerful round or a heavier gun (or both).

If the bullet twists one way creating torque in one direction and the barrel is twisting in the other immediately as the bullet leaves the barrel, wouldn't this result in more control-ability / less felt recoil?

[Gary13]

I don't know if it works, but my PX4 in .40 is softer shooting than the .40 Glocks that I have shot. Apples vs Oranges?

[aspenvalley]

[tankton]

The PX4 9mm I had was the lightest recoiling 9mm I've ever owned. The difference was subtle enough that I didn't notice it until the end of the day, when I picked up my Beretta 92fs and fired it. The recoil reduction is minor, and you will never be fooled into thinking its a 22.



My best guess as to how the recoil is reduced falls down to:

No vertical movement of any parts (except magazine stack). Even in a 92fs, the locking block (small as it is), is still slamming up and down. At the speeds the slide cycles at, that bit of mass starts proving some serious force. Even more so in a Browning tilting barrel.

I'd surmise there is some amount of counter-inertial force from forcing the bullet to rotate.Just like spinning a top takes some energy to get really fast, so does a bullet. While a 9mm isn't all that heavy or large, it still has some mass, some cross-sectional area, and some velocity. Enough that my bad math shows around 80,000 RPM (for a Glock 17 firing a bullet at 1100fps with a 1:9.84 twist rate). That being said, the contribution of this is likely minimal, but when added to the recoil force of the propellant, slide, etc, it might add up to be something (or be the straw that broke the proverbial camel's back). If the rotating barrel has been designed to ameliorate this twisting inertia, then it may somewhat balance out this twisting force. It really only needs to take the edge off of the twisting counter-force for the first 1-2" of travel, when pressure is highest).


So that's my hearsay. It may be wrong.

EDIT: more mental math. The rotational inertia thing is going to be very, very, very small. Less than 1/100th of a pound-inch.