When is recoil felt?

[JamesH]

All the autos seem to show the slide moving well before the bullet has left the barrel, and the recoil starting when the slide hits the travel stop.

[ronpistolero]

Hi,

This is getting very interesting.

Free Pistol, would you mind posting a pic of your comp up close? I do believe that comps may help increase accuracy because the gases, I understand, travel faster than the bullet and therefore may cause some deflection on the rear of the bullet that causes inaccuracies (albeit very small). The comp acts not only to deflect these gases away but also, depending on its direction, help reduce muzzle flip which finally helps in keeping the shooter's eye on the front sight.

I have read quite often about how accurized combat pistols, .45 and .38 semi-autos, can produce a "guaranteed below 2inch group at 50 yards". I am just wondering if a free pistol were designed with a blow back design to soften or delay felt recoil, with its fixed barrel against that of the semi-autos, if it would help improve scores. I have seen a couple of MG2s factory test groups and they were no more than 10mm c-t-c. I wonder if anyone can bench rest this gun, with its 6 inch barrel, at 50 meters and check how big its group would be.

Ron

[jipe]

If the case and slide are free to move, and for as long as this is the case, (and I take the point about gas pressure on the case adding to case-to-chamber friction), because momentum is conserved, the centre of gravity of the bullet - slide system (those masses moving in opposite directions, propelled by the same force) remains static. Perhaps counter-intuitive.

What you say would be true if the breech could move freely, but it cannot because you forget the breech spring that absorbs a big part of the energy, just like friction. This spring force is adjusted so that the breech become open only when the bullet leaves the barrel to avoid that high energy gaz escape thru the open breech. You can see this clearly on the high speed movies from the danish web site.

Secondly, the Steyr FP was a failure more due to the fact that it had a bad trigger mechanism and a awkward loading preceedure rather that the distance from the hand to the breech. I think it was also a bit "out there" for the market at which it was aimed.

Both are consequences of the low, forward position of the breech+barrel. It seems also (I never shot this pistol myself) that it is very little forgiving and that this is due to the big distance between hand and breech and sights heigh, both being other consequences of the very low barrel.

[Fred Mannis]

There is a write up at;

http://www.shootingwiki.org/index.php?t ... ing_Recoil

Interesting writeup. I was not aware that there is a .357mag autoloader on the market. Who makes the pistol shown in the illustration?

The 'good news' is that your body cannot react to the recoil by the time the projectile has left the barrel - your reflexes are not that fast. 'Flinch' is in your anticipation of a shot, not a result of the shot!

I have found that in sighting in a big bore pistol, like the 45ACP, there is a relationship between POI and the force applied to the pistol to reduce muzzle rise, especially with the lighter models where muzzle rise can be considerable. So controlled 'flinching' can be useful in delivering fast, accurate, followup shots with a light big bore pistol

[Shooting Kiwi]

Shooting Kiwi wrote:
If the case and slide are free to move, and for as long as this is the case, (and I take the point about gas pressure on the case adding to case-to-chamber friction), because momentum is conserved, the centre of gravity of the bullet - slide system (those masses moving in opposite directions, propelled by the same force) remains static. Perhaps counter-intuitive.

Jipe replied:
What you say would be true if the breech could move freely, but it cannot because you forget the breech spring that absorbs a big part of the energy, just like friction. This spring force is adjusted so that the breech become open only when the bullet leaves the barrel to avoid that high energy gaz escape thru the open breech. You can see this clearly on the high speed movies from the danish web site.

Yes, what I wrote was supposed unambiguously to indicate a theoretical situation. Excuse my tortuous language if this was not clear. In practice, as well as the recoil spring force, there is also the force required to cock the hammer, and friction, all of which resist the slide recoil. However, these forces are small, compared to the force from the propellant. It is the slide mass which is the major determinant of its acceleration.

Don't forget that the breech is only 'open' when the mouth of the spent case clears the breech, and this takes time because of the slide's slow movement, compared to that of the bullet.

David - what evidence do you have that the case starts to move out of the chamber only when the bullet has left the barrel? Barrel pressure drops so quickly when the cork pops out, that there simply ain't enough left to move the slide then. (In fact, the barrel pressure will transiently go below atmospheric after the muzzle blast.) If the case conveniently stuck in the chamber for a short time, there would be little need for delayed blow-back mechanisms: ammunition design could be arranged to retain the cartridge base and primer. I agree that the case to chamber friction can be increased by the case wall being forced against the chamber, but there can also be gas leakage between the case and chamber (to what extent in .22 I don't know), which is used effectively as a lubricant in machine guns, to ensure easy case extraction.

Look, if you want to make this complicated, remember that the bullet-to-barrel friction causes the gun to be dragged forwards with the bullet, if the case and breech are free to recoil!

Anyway, whatever the physics, the lack of movement of blow-back pistols, until the slide slams back against the frame, is elegantly shown in the videos.

[Dogchaser]

There is a write up at;

http://www.shootingwiki.org/index.php?t ... ing_Recoil

Interesting writeup. I was not aware that there is a .357mag autoloader on the market. Who makes the pistol shown in the illustration?

The 'good news' is that your body cannot react to the recoil by the time the projectile has left the barrel - your reflexes are not that fast. 'Flinch' is in your anticipation of a shot, not a result of the shot!

I have found that in sighting in a big bore pistol, like the 45ACP, there is a relationship between POI and the force applied to the pistol to reduce muzzle rise, especially with the lighter models where muzzle rise can be considerable. So controlled 'flinching' can be useful in delivering fast, accurate, followup shots with a light big bore pistol

Looks like a Desert Eagle 357 from the second pic.

Coonan also made a few different models.

[solomon grundy]

great thread.

Here's high speed video of a cut-away 1911..

http://www.trippresearch.com/media/move ... teway.html

[ausdiver99]

Interesting where this thread has gone!

Now, the reason why I asked the question!

My old Pardini K60 doesn't have a compensator. This contrasts the current practice. My dilemma is "is it worth fiddling around getting one made seeing as FWB, Morini et al have them!" Or is it a waste of time as the pellet long gone before the reaction to the compensator can assist reduce the recoil in an effective manner?

[Shooting Kiwi]

The answer lies above.

Perhaps the question should be 'How well is the compensator matched to the gun and the pellet?' Sorry, I don't know the answer...

[Muffo]

Interesting where this thread has gone!

Now, the reason why I asked the question!

My old Pardini K60 doesn't have a compensator. This contrasts the current practice. My dilemma is "is it worth fiddling around getting one made" or has the pellet long gone before the reaction to the compensator can assist reduce the recoil in an effective manner?

In Air pistol I dont think it really matters, but it does help with calling a shot. I shoot a model 2 FWB and my mother also has the same gun. mine is much better to shoot with the muzzle break on. It doesnt seem to do anything to help the accurace but reduces the varience in feet per second between shot. My mothers model 2 is actually more accurate as it will cut nearly one whole with even really cheap pellets and with good pellets will put even 1000 through a whole that no one could tell was any more than one whole. this may have been because it was a test gun that FWB brought over as a prototype. So i dont see inproving on the accuracy but it is way better to shoot with the muzzle break

[ronpistolero]

In 1991, I had a couple of comps machined for my FWB C20. The reason being I liked the way another FWB felt with its original muzzle break. I tried that of Nygord's but the weight probably (and its power adjustment) was really pushing the nose of the gun down below the orig aiming area. I figured I could do better by using T6 aluminum which weighed in at about 10 grams, and the exit hole made with a clearance so small that the nose of the pellet would go through but not the skirt. I liked the velocity set at 554fps with the yellow RWS, if my memory served me right, and it did produce quite a recoil for an air pistol,which I knew it didn't have any effect on the POI. It just felt better--no movement--after each shot fired. :-)

Regards,

Ron

[superstring]

In Air pistol I dont think it really matters, but it does help with calling a shot. I shoot a model 2 FWB and my mother also has the same gun. mine is much better to shoot with the muzzle break on. It doesnt seem to do anything to help the accurace but reduces the varience in feet per second between shot. My mothers model 2 is actually more accurate as it will cut nearly one whole with even really cheap pellets and with good pellets will put even 1000 through a whole that no one could tell was any more than one whole. this may have been because it was a test gun that FWB brought over as a prototype. So i dont see inproving on the accuracy but it is way better to shoot with the muzzle break

Are you saying your mom can put a string of 1000 shots through the same hole!!?? Mon Dieu!! :)

[Zico]

Once, at the range, when I was practising with my .22, some guy arrived with his S&W 29 in .44 mag. After firing a couple of cylinderfulls he came over, starting to brag about his .44s ability to "knock down anything". And his own ability to "hit anything within a one hundred yards". (He wasn´t).

I pretended I was quite impressed by his shooting with his awesome .44 mag, and he offered me to test fire that "awesome piece". I was allowed to load the cylinderfull of cartridges. With intention I loaded a spent case among the live rounds...
Just as I raised my arm to fire, I told "the bragger" the gun felt too heavy for me, and I would not hurt my hand firing his awesome gun.
He then proudly grabbed the revolver, and started firing. He god a few "bangs", with plenty of recoil, that is for sure.
But, then "surprisingly", he got just a "click". But, even more surprising, that "click" was accompanied by considerably "recoil" (!)
He looked at me, a bit embassased, well aware that I had witnessed his awesome flinching and jerking of the trigger...

That made my day.

I think his "recoil" started prior to the actual hammerfall...
(The late Elmer Keith wrote in his book "Hell, I was there": To shoot a .44 mag well doesn´t take muscles. It takes mind.")

[Muffo]

In Air pistol I dont think it really matters, but it does help with calling a shot. I shoot a model 2 FWB and my mother also has the same gun. mine is much better to shoot with the muzzle break on. It doesnt seem to do anything to help the accurace but reduces the varience in feet per second between shot. My mothers model 2 is actually more accurate as it will cut nearly one whole with even really cheap pellets and with good pellets will put even 1000 through a whole that no one could tell was any more than one whole. this may have been because it was a test gun that FWB brought over as a prototype. So i dont see inproving on the accuracy but it is way better to shoot with the muzzle break

Are you saying your mom can put a string of 1000 shots through the same hole!!?? Mon Dieu!! :)

yes i am! As can I. When the gun is clamped in a vice. what i am saying i cant see the advantage of a compensator v a muzzle break

[superstring]

Interesting where this thread has gone!

Now, the reason why I asked the question!

My old Pardini K60 doesn't have a compensator. This contrasts the current practice. My dilemma is "is it worth fiddling around getting one made seeing as FWB, Morini et al have them!" Or is it a waste of time as the pellet long gone before the reaction to the compensator can assist reduce the recoil in an effective manner?

I think the definitive answer to your question is to be found in the article referenced by JulianY


http://www.shootingwiki.org/index.php?t ... ing_Recoil

Very little if anything can be done to reduce primary recoil, doing so would reduce bullet velocity; however, we can control the effects. Because of the vectors from the mechanics of the body some of the energy dissipates not backwards rotationally and upwards. The use of perforated barrels can help reduce the “rise” so the attempt to maintain sight alignment until the bullet has left the barrel........

and

.......The most significant effect on the shooter of recoil is sight alignment. This is particularly the case for Rapid Fire Pistol and the 10-seconds series of Standard Pistol when the sights must be re-acquired for the next shot. Prior the Athens 20004 Olympic Games the use of perforated barrels and compensators and .22 short ammunition were permitted for Rapid Fire Pistol event. Contrary to popular belief; recoil control and the ability to re-acquire the sights for a second shot are the primary reason for the two handed shooting techniques used in "Combat" shooting disciplines.

Primary recoil begins the moment the bullet starts its' travel down the barrel. This is when accuracy will be effected and the only way to "compensate" is with sight adjustment. As Muffo noted, reducing secondary recoil with the use of a compensator may help the shooter's ability to call the shot (and make the gun a little "nicer" to shoot)...... but will have little or no effect on accuracy. As far as accuracy is concerned, the old mantra "sight alignment and trigger control" is what really matters!

[Muffo]

that s exactly what i mean being able to call a shot is vital to improvement. that is also one of the main things that makes an ap good in the first place. even a cheap rohm will still put all the shots through the middle but it isnt as good as the top guns as its shootability isnt as good.

[2650 Plus]

To deal wih the orriginal question at least two issues must be .considered. The first is whether a surprise shot has been delivered. This deals with the shooters reaction time. The second is when recoil really starts to occur. Based on the first issue , we have to consder the reaction time of the shooter, witch on a reasonably normal person is about .33 hundreths of a second. The secomd based on the opposite reaction to the movement oy the projectiol is immediate. There fore percieved recognption of recoil depends on the shooters reaction time and the other issue is governed by Nuetons law of relativity. this was a long discussion and very interestin to consider.But it really has very little to do with firing the perfect shot. Good shooting Bill Horton

[Richard H]

"Nuetons Law of relativity"????

Do you mean Newton's Three Laws of Motion or Einstein's Theory of Relativity?

[EdStevens]

The gripping effect on the chamber wall of a .22lr case is insignificant

I freely admit I don't know the answer, but I do question that. The lowly .22 LR is in fact a high pressure cartridge, exerting about 24,000 pounds per square inch. Now, I know it's not much surface area, but at those kinds of pressures I would think the gripping effect could well be very significant in keeping an action closed until the pressure drops?

[2650 Plus]

I really pulled a brain flatuation just as I was finishing my thought but I still got something out of the mistake. The lurker is still on the net and correcting. spelling and mis statements .You do well on the rules, but i can't find any of your posts that deal with shooting skills. Good lurking Bill Horton