a touch of torque

[redhedrednek]

Today I was shooting with my dad. I shoot a lot and he taught me well so neither of us are new to anything firearm related. I recently acquired a 44 mag super blackhawk and was shooting. Dad kept asking if I was scared of the gun because of the way it recoiled. Proper -imho-stance with handcannon range shooters allows upward recoil so it is bent elbow firm but not rigid grip. I explained and he decided he needed to try it. Gun did exactly as he described my "flinch" we discussed and determined that there was some amount of torque applied when the rifling engages that was causing the odd reaction. Obviously there is torque to make the bullet turn with the rifling and with more manageable loads it is not felt as much as with handcannon rounds. Long story short...has there ever been any study of what torque a round generates and how that effects felt recoil?

 

[ljnowell]

SA revolvers, especially those with the plow handle grip recoil differently. Its not from the bullet engaging the rifling though.

 

[The Lone Haranguer]

That gun will rear straight up in your hands. This is a characteristic of the design of the grip. A double-action revolver will not torque upward as much.

 

[captain awesome]

I have ran some max loads through my 500 Mag, and it torqued. It had the muzzle break on the top but not the bottom so there wasn't much muzzle rise, but the gun would torque in my hand. I am not talking just a little bit, it torqued a LOT. Really an odd phenomenon. That gun weighed a lot more than a Blackhawk, and was double action, but it seems if it was so very pronounced in the 500, you might feel it in a real heavy loaded 44.

 

[siglite]

Yes. I've heard high-power 30 cal shooters from the old days talking about left-hand versus right-hand rifling matched with left-hand v. right hand shooters, and the purpose was the rotational torque pushed into the barrel. It's the equal and opposite reaction of spinning a bullet to 200,000 RPMs in a couple of feet.

It's reported to me to be there. But I've never personally noticed/experienced it.

 

[TheNev]

When my girlfriend shoots my CZ P-01, I noticed that her wrist rotates counter-clockwise.

I haven't noticed it when she shoots my other handguns.

 

[eocoolj]

The gun rearing up in your hand is caused by the force of the recoil being translated into a rotational force. This is because the recoil is pushing straight back but your hand is not directly behind it to directly counter-act this force. It has been awhile since I took a statics course, but this is the reason why all the newer military rifles (starting with the FG-42), have a straight rather than slanted stock. If you had a pistol with a grip like the below drill, the force of the recoil would be pushing almost straight back on your hand, and the tendency of the gun to rotate in your hand would be greatly diminished. You might have a hard time holding it though, with all the weight concentrated so far out.

 

[Fishslayer]

Shooting the same loads weak handed in both my KP90 & 1911 the Ruger torques noticeably harder than the RIA. Felt recoil is not much different. My guess would be that the torque felt would vary with rifling and grip style, angle, etc. SA revolvers are generally very different from DA & semiautos.

 

[Shimitup]

I'm sure there's some engineers here that can calculate the amount of energy required to accelerate a whatever weight bullet to somewhere around 50'000 RPM. I would think that would apply a noticeable torque. Randall made their lefthand 1911's with lefthand twist so they would have the same feel to left handed shooters.

 

[Jim K]

Torque from the rifling is certainly real and is especially noticeable in the 1911. The amount depends on the momentum of the bullet, that is mass times velocity. So a light bullet at low velocity will have less torque (and less recoil) than a heavy bullet at high velocity.

But the statement that " Randall made their lefthand 1911's with lefthand twist... " is a bit puzzling. All Colt Government Model and all U.S. GI M1911's and M1911A1's have left hand twist, and so do many of the clones.

Torque aside, if the barrel is not on the line of the center of gravity, the gun will recoil around its center of gravity. With the ordinary gun design, that means the barrel will rise. If the bore is on the CG, the recoil will be straight back. With a gun like the Colt SAA, with a lot of its weight below the line of the barrel, recoil will drive the barrel up and the butt down so the gun "rolls" in the hand.

Jim

 

[Shimitup]

Jim, you're absolutely right. I just got turned around, the lefthand gun has a righthand twist.

 

[GoWolfpack]

Are we talking about muzzle rise perpendicular to the bore or twist parallel to the bore?

 

[adelbridge]

I cant tell the difference when shooting a rotating barrel gun like the PX4

 

[barnbwt]

I'm sure there's some engineers here

I rushed over as soon as I wanted to

I calculated the loads caused by rifling torque in the stress analysis of a revolver I'm prototyping:

200gr
D = .357 bullet
C = 1:16" twist
P = 90,000psi (this was for a proof load)

The component of force (F=P*A)
in the radial direction, (F*r=T)
along the rifling angle (R=atan(D*pi/C)) (I assume no bullet rotation for easy and conservative torque calculations)
gives a net torque (t=T*sin(R))
calculated as: ~114in-lbs or 9.5 ft-lbs **correction noted--t'anks Jamo (my design calcs are in inches & pounds so I still good *whew!*)

Now, this is just for an instant, and much of this torque impulse is dampened by the weight of the gun and shooter. But the value is proportional to chamber pressure and bullet weight, and increases faster than that for radius and rifling angle. It is inversely proportional, however, to gun weight and grip distance below bore axis.

From shooting light to heavy loads in my TRR8, I've come to understand the designs of the different grips out there:
-The old Bisley puts your hand so far below the center of mass of the pistol that you easily resist the barrel torque, and causes recoil torque to be more pronounced (muzzle flip)
-A closer-in DA grip like mine resists recoil torque much more, pushing the hand straighter back, but the shorter bore-axis grip location magnifies torque more. If I screw up and don't hold the grip firmly enough, my wrist is very noticeably torqued as it rotates back (almost painfully, once)
-The only other grip style I'm aware of is the Chiappa Rhino which is nearly in line with the bore axis. Very little noticeable flip is seen when it is shot, but I'll bet hot n heavy loads in that light aluminum frame will twist the shooter quite a bit.

At the end of the day, any twist force is dwarfed either by muzzle flip or straight recoil forces, and is hardly noticed in most cases. I'd bet it's more of an issue for folks shooting for fine-tuned consistency or speed with large, fast loadings like 44mag or higher . I'd also bet that the human arm is better at resisting torque in one direction than the other (which may or may not be the same ideal direction for reducing the Coriolis Affect. I doubt that troubles many pistol shooter, though )

TCB

 

[Jim K]

Hi, GoWolfpack,

We are talking about twist around the axis of the barrel caused by the spinning of the bullet, not the movement of the barrel caused by reaction to the forward movement of the bullet.

The drill pictured above does have that kind of torque. It doesn't have recoil back because there is no backward force when it is not drilling into something, but it will have a twist due to the motion of the armature in the motor.

Jim

 

[Quoheleth]

Torque = manifests as twist.
Recoil = manifests as muzzle rise.

Shooting a single-action (e.g., 1873 clone), you get lots of upward-driving recoil, largely due to the grip style.

Automatics and DA revolvers still have upward-moving recoil, but it's less dramatic until you get up to the big-boys.

That said, the most uncomfortable loads I've shot were full-house 125gr .357 Magnums. Not only was there recoil (upwards) there was torque, twisting my hands laterally from my starting position. I can't say I've noticed it as much with heavier bullets in the same gun. I don't notice torque at all in my .45 Colt SAA clone.

Q

 

[Jaymo]

114 inch lbs would be 9.5 ft lbs.

1368 inch lbs would be 114 ft lbs.

I think you got your conversion confused.

It happens.

I would think jacketed rounds would impart more torque than lead boolits, due to higher friction.

 

[GoWolfpack]

I wasn't really sensing unification on the issue. Some folks seemed to be talking about recoil energy, some about torque along the axis of the barrel.

I was warned the first time I used a drill that size to be very careful as it broke through the steel, since it could catch at the last and break my arm if it was turning full speed. Helped me form a respect for power tools, that did.


I've been considering buying a 500 magnum, perhaps I'll be able to report with more authority later. I suspect, however, that any torque along the bore axis will hardly be noticed in the shadow of significant recoil force perpendicular to the bore; such is the case with my 44 magnum.

Hi, GoWolfpack,

We are talking about twist around the axis of the barrel caused by the spinning of the bullet, not the movement of the barrel caused by reaction to the forward movement of the bullet.

The drill pictured above does have that kind of torque. It doesn't have recoil back because there is no backward force when it is not drilling into something, but it will have a twist due to the motion of the armature in the motor.

Jim

 

[beag_nut]

I hope that the photo I want will be displayed correctly, or can be clicked on for downloading. At any rate, it shows a S&W revolver the instant after firing, when the bullet has just left the barrel and is about one foot from it. One can clearly see the muzzle blast and cylinder gap blast. One thing is missing, though: any change in the hands holding the weapon. Recoil has not even begun to affect the shooter's grip, mainly because the bullet weighs at least less than 1.5% of the weight of the revolver. The recoil (equal to the energy imparted to the bullet) hasn't even overcome the inertia of the gun/hands. Any "torque" effect would have zero effect (or very close to that)on the placement of the bullet. Though it might still twist one's grip.

http://upload.wikimedia.org/wikipedia/commons/2/23/Bullet_coming_from_S&W.jpg

If someone else can figure out how to display this pic, please do so.

 

[GoWolfpack]

 

[beag_nut]

Thanks, GoWolfpack.
beag_nut

 

[Jaymo]

Look at that flash through the cylinder gap.

 

[Lost Sheep]

Look at that flash through the cylinder gap.

Take a look at where the left-hand thumb is.

There's a fellow in Missouri (if I recall correctly) who made his thumb pretty ugly by placing it in line with the blast from the barrel/cylinder gap of an 8" 460 S&W XVR. Looked a lot worse than it was (but still hurt worse than it looked, I bet). He didn't even lose his thumbnail, but it sure looked like he would, even to his doctor.

Check out these threads

http://forums.outdoorsdirectory.com/showthread.php?t=25870&page=1
where I first saw mention of it and
http://www.ar15.com/forums/t_1_5/66...y__Warning__graphic_pics_pg_15_17.html&page=1
where the original poster and victim started. Go to page 9 if you want pictures. Those look a lot better than the first ones I saw, but those links don't work for me any more.

Back on track:

I've been considering buying a 500 magnum, perhaps I'll be able to report with more authority later. I suspect, however, that any torque along the bore axis will hardly be noticed in the shadow of significant recoil force perpendicular to the bore; such is the case with my 44 magnum.

My (magna-ported) 4 5/8" Freedom Arms torques my wrist (to the left) a lot more than my (unmodified) 7.5" Ruger Super Redhawk firing the same 454 Casull full-power loads.

I don't believe I have noticed any significant torque in any of my other guns, 357 Magnum, 44 Magnum, 45 Colt or 45 ACP at any power level, though the 44 Mag Single Action might have a little detectable. I traded off my 44 Mag Blackhawk several years ago and my current 44s are all double-action grip profile so I may not remember it so well.

My friend's 4" 500 Smith does not seem to have very detectable torque, either, but that may just be because it is overshadowed by the recoil. With full-power loads you really have to hang on tight, even with the muzzle brake. I have not examined the muzzle brake to see if it imparts an opposing torque to mitigate the bullet's torque-recoil and I probably won't get to examine it for a while.

I would think jacketed rounds would impart more torque than lead boolits, due to higher friction.

I would think the friction (as far as torque is concerned) would be irrelevant. The rifling would make it so.

Lost Sheep

 

[Jim K]

"Recoil = manifests as muzzle rise."

Not exactly. A firearm recoils around its center of gravity. If the CG is in a direct line with the barrel, recoil will be straight back and there is no muzzle rise. If the barrel is below the CG, recoil will cause the muzzle to go down and the butt to rise. If the barrel is to one side of the CG, as in double barrel guns, the muzzle will go in the direction, left or right, of the barrel as well as up.

Jim