Finally the Recoil Argument is Settled

[Deleted]

Proof positive that recoil begins at the instant of ignition. 
If you have a player that can slow down this video even more, it helps to make things more obvious.
What we see is the hammer drop, flash from the barrel cylinder gap, followed by flash from the rear of the chamber against the recoil shield AND the beginning of the pistol's backward motion.  THEN we see the bullet exit the muzzle, followed by the expanding gases behind it.

Your eyes have it.

[Walter]

Yep....moving backwards before the bullet exited, just like we said it should. Newton sleeps well tonight.
I like the illustration of the mechanical couple created by the bullet passing through the gel a few inches above where it's resting. That lever arm rotated the gel block clockwise. Watch all the crazy gyrations as the forces are being redirected through the gel to the base of the tree stump.
Cool video.
BaM's gonna be pissed.

[Deleted]

Jan 16, 2017 20:33:37 GMT -5 Walter said:

Yep....moving backwards before the bullet exited, just like we said it should. Newton sleeps well tonight.
I like the illustration of the mechanical couple created by the bullet passing through the gel a few inches above where it's resting. That lever arm rotated the gel block clockwise. Watch all the crazy gyrations as the forces are being redirected through the gel to the base of the tree stump.
Cool video.
BaM's gonna be pissed.

Yep, that's called hydrostatic shock.  Notice the huge temporary wound cavity the bullet causes.  You may see a very small hole in the skin since skin is flexible, but depending on what caliber and velocity of the bullet, internal damage to a body can be devastating.

BTW, have you ever seen jello fart before??
             

[bamorin]

notice that this isn't a closed system due to the system being open at the front of the cylinder. That open there is no different than the open at the end of the barrel. a closed system firearm recoils when it's no longer a closed system.
ie when the bullet exits the barrel.

which is why a slow round from a revolver shoots naturally higher than a fast round from same gun. the barrel is rising more due to recoil while bullet is still in barrel.

we've been over this.

[Deleted]

Gotta agree with ba.

[bamorin]

one other thing to note in this video.......which way does the jell block move in relation to bullet travel?
the direction of the bullet path, or back and to the left, back and to the left, back and to the left?

[Deleted]

Jan 17, 2017 7:59:40 GMT -5 bamorin said:

notice that this isn't a closed system due to the system being open at the front of the cylinder. That open there is no different than the open at the end of the barrel. a closed system firearm recoils when it's no longer a closed system.
ie when the bullet exits the barrel.

which is why a slow round from a revolver shoots naturally higher than a fast round from same gun. the barrel is rising more due to recoil while bullet is still in barrel.

we've been over this.

Wrong.   There is no such thing as a "closed system" in a firearm.  Even the firing pin hole on a single shot will leak gases, since no cartridge is going to perfectly seal the chamber.   This is why your spent brass has gunpowder burns on it, and the breechface does too.  Gas begins escaping as soon as it gets past the case mouth, in any direction that it can.  Recoil begins at the instant the primer flash ignites the gunpowder and the gas produced begins to expand.

 A slower bullet prints higher from ANY gun.   Apparently you have never shot 230 grain and 185 grain bullets in a 1911.  A lot of semiautos have elevation adjustable rear sights for a reason.

I slowed this down to 1/4x the normal speed of the video, and you can plainly see the slide begin to move back BEFORE the bullet exits the muzzle.
Argument over.

[Deleted]

Jan 17, 2017 9:01:59 GMT -5 @kelliers said:

Gotta agree with ba.

You are wrong, too.

[Deleted]

Jan 17, 2017 10:14:11 GMT -5 bamorin said:

one other thing to note in this video.......which way does the jell block move in relation to bullet travel?
the direction of the bullet path, or back and to the left, back and to the left, back and to the left?

What difference does that make?  The gelatin block moves in relation to the hydrostatic shock being applied to it by the bullet.    It expands, but doesn't STAY expanded.   Gel offers much less resistance than a solid block of wood, so that means nothing.

[bamorin]

[Walter]

Jan 17, 2017 10:53:02 GMT -5 @muttmk2 said:

Jan 17, 2017 10:14:11 GMT -5 bamorin said:

one other thing to note in this video.......which way does the jell block move in relation to bullet travel?
the direction of the bullet path, or back and to the left, back and to the left, back and to the left?

What difference does that make?  The gelatin block moves in relation to the hydrostatic shock being applied to it by the bullet.    It expands, but doesn't STAY expanded.   Gel offers much less resistance than a solid block of wood, so that means nothing.

There are two things happening to the gel block. First, there is the axial force of the bullet pushing the block in the direction of the bullet travel as the bullet's force is transferred by the block. Second, because the bullet is a few inches above the base of the block, it causes a rotational force in the block, which is why it pivots on the rear corner. Had the block been shorter, the rotational force would likely have rolled the block because the rotational force would overcome the mechanical couple created by gravity or pushed it toward the direction of the bullet travel as the axial load overcomes the friction of the gel surface on the base..

[Deleted]

Jan 17, 2017 11:52:35 GMT -5 Walter said:

Jan 17, 2017 10:53:02 GMT -5 @muttmk2 said:

What difference does that make?  The gelatin block moves in relation to the hydrostatic shock being applied to it by the bullet.    It expands, but doesn't STAY expanded.   Gel offers much less resistance than a solid block of wood, so that means nothing.

There are two things happening to the gel block. First, there is the axial force of the bullet pushing the block in the direction of the bullet travel as the bullet's force is transferred by the block. Second, because the bullet is a few inches above the base of the block, it causes a rotational force in the block, which is why it pivots on the rear corner. Had the block been shorter, the rotational force would likely have rolled the block because the rotational force would overcome the mechanical couple created by gravity or pushed it toward the direction of the bullet travel as the axial load overcomes the friction of the gel surface on the base..

Either way, the bullet wins!

[Deleted]

Jan 17, 2017 11:05:17 GMT -5 bamorin said:

Thank you!!
If you freeze it at the 00:27 mark, you see the slide is moving backwards, the breech is unlocked and gases are escaping from the ejection port while the bullet is STILL in the barrel.  Now what causes the slide to travel rearward and unlock the breech?   RECOIL.

Recoil begins BEFORE the bullet leaves the barrel and your video proves it.

[bamorin]

at 25 i see the gas escaping around bullet, at 27 i see muzzle flash. bullet is out. what causes the slide to move back? the case pushing against the bolt face. the reason it can push against the bolt face is the pressure pulse has dropped below 12,000 PSI. why would it drop from 21,000 psi to 12,000 psi? Nothing plugging the barrel. Slide doesn't move until the brass pushes it. at 21,000 psi the brass case is "welded" to the chamber. It cant slide back....ya wanna know why?

[Deleted]

Jan 17, 2017 19:07:10 GMT -5 bamorin said:

at 25 i see the gas escaping around bullet, at 27 i see muzzle flash. bullet is out. what causes the slide to move back? the case pushing against the bolt face. the reason it can push against the bolt face is the pressure pulse has dropped below 12,000 PSI. why would it drop from 21,000 psi to 12,000 psi? Nothing plugging the barrel. Slide doesn't move until the brass pushes it. at 21,000 psi the brass case is "welded" to the chamber. It cant slide back....ya wanna know why?

I suggest you consult an optometrist.

I know what you WANT to see, but what you want to see just isn't there.

And you are wrong.  The slide and breech are locked together for a short distance to allow pressure to drop BEFORE they unlock, but they start moving backwards TOGETHER at the instant of ignition.  The pressure is high while the bullet is in the barrel AND the barrel and slide are already beginning to recoil,and after the bullet exits the muzzle and pressure drops to a safe level, the slide and breech CONTINUE their rearward motion.  The barrel stops rearward movement, but the slide continues, extracting and ejecting the empty case and then returning forward to chamber a fresh round.

The video you posted proves what I have said.  I don't know how to say it any more plainly.


EDIT:  We will settle this very simply.
When does recoil begin in a simple blowback semiauto design?  INSTANTLY.  There is nothing mechanical to retard the movement of the bolt so that "pressure can drop."
When the powder gases begin to expand as they burn, they exert force equally in all directions.  This is a simple law of physics and nothing can change that.  

I'm done.