Question about recoil

[adair]

I understand that when shooting a .22 standard blowback pistol, the recoil is felt long after the bullet leaves the muzzle as momentum is conserved for some time by the slide moving backwards.

However, in a free pistol design (e.g. TOZ, Morini), is it true that recoil is experienced from the moment the cartridge is ignited? That is, while you might not "feel" the recoil until after the bullet leaves the muzzle, does the muzzle nonetheless rotate upwards to some extent prior to the bullet's exit?

But I guess since this movement is constant (assuming one uses the same ammunition) it has no effect on precision?

[NikNak]

As a novice FP shooter(I have the scores to prove it ...), I have found that recoil with my Toz really varies based upon proper hold, grip etc ... When done correctly, it just sits back into my hand on recoil, but with the improper grip, there is muzzle movement. Usually, when it feels good, the shot is good also.

When shooting NRA Bullseye(Expert class), I do not see, or feel the same thing. I actually shoot high velocity in my Bullseye 22 and it scores better than SV... less barrel time?

[Rover]

The answer to your question is "yes".

While the recoil may be constant, there is a change in the speed of the recoil depending on the "weight" caused by a varying grip.

[RandomShotz]

Recoil is the the gun's reaction to a mass accelerating forward, i.e., the bullet and to a much lesser extent, the hot gases behind it. It starts as soon as the bullet starts moving so the gun starts rotating up at the same time. The mass of the gun is much greater than that of the bullet so the acceleration is much less, but it is there. When the charge ignites, it exerts as much force on the casing held in place in the chamber as it does on the bullet. F=MA and there's no way around that.

If you need a demonstration, try this. Set a properly sighted-in (unloaded) gun on a flat surface upside down, that is, on it's sights. This places the sights in a horizontal plane. Now look at the angle the barrel makes with the surface - it is pointed up. This is very noticeable with high power guns, but I think you will be able to see it with a .22. This means that in the normal firing position, the barrel is pointing well below the point of aim when it it sighted on target and will rotate up before the bullet leaves the muzzle. This is why consistency of hold is so critical for accurate handgunning - a little more or less pressure from your pinky will have a noticeable effect down range.

Roger

[Shooting Kiwi]

You're right, adair, however the recoil impulse from a free pistol, revolver, etc., whilst not varying (significantly) from shot to shot may result in different movements of the gun if the recoil impulse is reacted differently by, for instance, different grip strength. I suppose that's one reason why free pistol is so difficult.

If you look at http://karlslundesport.dk/ and click on the site map, then select 'Functionstest', you will find fascinating slow-motion videos of blow-back pistols firing. There is no perceptible movement of the pistol until the slide slams against its stop. Not all shooters appreciate this ...

[Richard H]

Recoil is Newton's Third Law of Motion, so theoretically as a force is applied to the projectile an equal and opposite force (which we call recoil) is also generated. In reality the "felt recoil" requires our nervous system to register it, which adds some delay, but recoil is there the exact same time as the projectile starts its acceleration in every firearm.

If you want to know the actual force of the recoil see Newton's Secon Law of Motion.

[adair]

Thanks for the informative responses (and the videos, Shooting Kiwi). I shoot FP and now better appreciate why a consistent grip is so important.

However, considering recoil is a factor in shot precision, why aren't free pistols with lower barrels (e.g. Steyr FP) more popular since presumably the recoil should raise the muzzle less? Alternatively, would it be helpful to have some sort of blowback design in a free pistol considering it would delay muzzle flip until after the bullet leaves the gun, thereby eliminating muzzle flip as a shot variable?

Last, for a TOZ free pistol, is it then true that having a compensator that reduces muzzle flip will help reduce errors caused by, for example, slight changes in grip pressure?

[Gwhite]

It might be possible to build a "recoiless" free pistol. Sort of like the old FWB 65 air pistols. The barrel & some of the action is released on firing, so that it can slide back on rails under recoil. The shooter doesn't feel the recoil until after the pellet left the bore, at which point the sliding mass hits a stop. This was important in the FWB 65, because the "recoil" was dominated by the motion of an internal spring powered piston with a fair amount of mass.

For a free pistol, the amount of mass required in the sliding barrel/action and the length of recoil rail might be an issue, but it could work in theory. Back of the envelope calculation: You have 2.6 grams (40 grains) of bullet traveling ~ 30 cm. If you allowed the action & barrel to slide 1 cm, you only need 30 times the bullet mass for the sliding assembly to ensure that the bullet leaves before the sliding assembly hits the stop & transmits the recoil to the frame & grip. That says it's very do-able. You would have issues with wear on the rails, but with the rear sights mounted on the sliding barrel assembly, it shouldn't be a big deal.

Especially with an electronic trigger, it would be relatively easy to "float" the moving assembly from the trigger, although sliding contacts might give some reliability issues. An optical link would be perfect.

Fun idea. Anyone want to make a prototype?

[BenEnglishTX]

However, considering recoil is a factor in shot precision, why aren't free pistols with lower barrels (e.g. Steyr FP) more popular since presumably the recoil should raise the muzzle less?

I'm not a competitor, just an amateur who likes playing with a couple of free pistols I own, and I find this question quite interesting.

Along the same lines (reducing the sources of instability before the bullet leaves the barrel), I've often wondered why free pistols have such long barrels. As the pistol silhouette shooters taught the rifle shooters, all else being equal, shorter barrels are more accurate than longer ones. (In those games, barrel rigidity is a good thing and the shorter a barrel is, the better the diameter-to-length ratio, i.e. shorter barrels, even of the same diameter, are functionally thicker and more rigid.)

So why aren't free pistols built with short barrels? If you need a longer sight radius, the high-power rifle shooters have plenty of "bloop tubes" to sell that put the front sight way out past the muzzle.

I feel sure this has been thought of, experimented with, and discarded in the past. It seems that everything that can be done to a free pistol already has at some point in the past and the current standard configuration is probably what works best. But I am curious if anyone has tried it.

[BEA]

Shorter might be better in some instances, but there comes a time when going shorter ceases to be an advantage. Otherwise, the rifle shooters would have really long bloop tubes and really short barrels. A free pistol barrel is already approx 12 inches long, which in comparison to a rifle, is short. In terms of velocity, the optimum length for a 22 LR is approx 12 to 14 inches. Perhaps this velocity is where maximum stabilization is achieved. If you look at most of the top quality 22 LR ammo, the velocities are running approx 1180 fps. This speed must go along with max accuracy. In the firearms where top accuracy is important, the barrels are likely made in a length that will closely produce this desired fps. Eley Tenex ammo that is doing approx 1180 fps out of my FP is only going about 980 fps out of my Pardini SP...and my Pardini is not nearly as accurate. I realize that a lot of this is due it being a semi auto, but I wonder what size groups it would shoot if it were a fixed system like the FP...interesting question. I volunteer someone else to cut their FP barrel off to answer this question. I like mine the way it is.

[BenEnglishTX]

Shorter might be better in some instances, but there comes a time when going shorter ceases to be an advantage. Otherwise, the rifle shooters would have really long bloop tubes and really short barrels.

No, the rifle shooters continue to use long barrels because they're shooting at longer distances and need more bullet velocity from bigger cases, thus mandating longer barrels. (Various rules also play a part.) What made pistol silhouette shooters so vexing to the rifle guys was that we didn't need 600-1000 yard capabilities. We were limited to 200 meters. When Remington came out with their 7BR, 14" barrel XP pistol with what looked to the average rifleman to be a ridiculously ultralight barrel, it just made them crazy that out to 200 meters, those things would put even high-end factory rifles to shame in the accuracy department.

I'm not convinced that short barrels ever become a disadvantage, assuming all else is equal. Of course, all else is never equal.

I volunteer someone else to cut their FP barrel off to answer this question. I like mine the way it is.

I like to do weird things with pistols. I feel an idea forming in my head that may cost me some money and I have you to blame. Thanks. :-)

[BEA]

The type of shooting being considered is a factor. My comments were with 22 LR in mind, where barrel harmonics and added velocity are not considered in the same light. For long range shooting, you need length for the extra velocity. Shorter barrels do become a disadvantage if they fail to produce the velocity needed for the desired wind bucking qualities or trajectory. However, if you are a benchrest shooter, shooting groups at 100 yards for instance, shorter and fatter (depending on class) is the order. With a 22 LR, once you get over approx 14 inches, you start to loose velocity because the powder charge has expended all its energy. The optimum barrel length for centerfire rifle cartridges is different depending on case capacity and the burning speed of the powder.

Ben, I agree with you in theory. A shorter barrel that produces the same ballistics as a long barrel, should be at least equal in terms of accuracy. The problem is that with a given cartridge, you cannot have it this way. Like you said, "all is never equal."

[scerir]

However, considering recoil is a factor in shot precision, why aren't free pistols with lower barrels (e.g. Steyr FP) more popular since presumably the recoil should raise the muzzle less?

There are Portuguese and Russian FP with extremely low barrels. In this case it seems that even slight changes in grip, and in grip pressure, cause a *larger* spread of the points. Not to mention that sometimes you get a negative muzzle flip, sometimes a positive muzzle flip.

[NikNak]

Shorter might be better in some instances, but there comes a time when going shorter ceases to be an advantage. Otherwise, the rifle shooters would have really long bloop tubes and really short barrels. A free pistol barrel is already approx 12 inches long, which in comparison to a rifle, is short. In terms of velocity, the optimum length for a 22 LR is approx 12 to 14 inches. Perhaps this velocity is where maximum stabilization is achieved. I volunteer someone else to cut their FP barrel off to answer this question. I like mine the way it is.

I was an active prone & position SB shooter a few years back and there were a few guys shooting 16" barrels (to keep them ATF legal). Their theory related to less barrel time with Std Vel ammo. They had rather lengthy bloop tubes as the sight length varied based on age and front sight focus. Anschutz even made the the shorter barrels and they still might ... for balance purposes, I think most went back to full length with shorter bloop tubes because they were having issues with their barrel tunners being able to catch back up to where they had found the sweet spot. I think there are those in the BR community that still shoot short barrels.

As for FP, I need to work on my grip, sight alignment and trigger before I would see any assistance from shortening the barrel to reduce barrel time. Actually, I need to work on a lot of things....