A while back Thos. M Burgess wrote that when comparing the recoil of a 416 Rigby and the 416 Rem. the Rigby was more comfortable to shoot. Would this also apply to say a 338 Win. and the 338 Rem Ultra Mag if the Rem was loaded to the same velocity as the Win. Also the 300 Ultra to 300 Win velocities? Or does this only apply to larger bore diameters?

Thanks Hart

According to the mathematical formulas, recoil is determined by the velocity of the projectile, the mass of the projectile, the mass and velocity of the ejecta, and the weight of the rifle.

Since a larger case necessitates a larger charge, my first reaction is "you have that backwards". But, perceived recoil does not always follow the formulas. FWIW, Dutch.

Even if you do get less recoil, which sounds mathematically impossible to me - you'd still have more muzzle blast. The only thing the larger case will deliver is lower pressure, which can potentially be important in very hot hunting conditions.

Couldn't have said it better, Dutch. These types of odd notions seem to crop up with regularity.

Now, what may indeed be true is that the larger capacity case, while using more powder, will also generate less pressure, and in particular less muzzle pressure. This has nothing to do with recoil, but it may affect the loudness of the report. You'd be surprized at the number of shooters who will swear that a very loud gun recoils more than a quieter one, no matter the actual facts. That's one reason that I find boom boxes, cherry bomb tail pipes, and muzzle brakes to be useless and counterproductive scourges, advocated primarily by Phillistine troglodytes.

I think what he means is using the same charge weight with a larger capacity. If that is the case, recoil could go down slightly since the larger cartridge would be producing less pressure and therefore less gas escaping the muzzle.

Pressure at the same velocity may be less, but I don't think "peak" pressure has anything to do with recoil, pressure at the muzzle may have an effect on muzzle blast, but shouldn't add to actual recoil. In that situation, the Rigby holding more powder, probably slower burning too, could have higher muzzle pressure and more blast... but that's all, I'd think. Were both rifles equally designed, "stocks", bbl etc?

My brothers Win 70 300 Ultra syn. was a bitch for recoil, my 700 Lam. isn't as bad. I attribute that to the stock in that situation.

Could one not compare it to a water hose? If the water is under lots of pressure there is considerable back trust (rocket effect??) as compared to when there is less water pressure.

Hart

hart--

The water has difference velocity and that's why the recoil is different.

I also notice the difference in the APPARENT recoil between rifles of the same physical recoil figures.

Physics tell us a rifle weighing the same, at the same velocity, and same powder charge WILL have the same number of foot pounds reacting against the shooter, but it does NOT tell us over what span of time that peak occurs.

There's a big *apparent* difference between a hundred foot pound of push and a hundred foot pounds applied with a ball bat.

I would have to say that a reduction in pressure does in fact reduce felt recoil, even in moderate calibers such as the 308 and 30-06 comparison. The 308 is noticeably sharper and more abrupt in recoil than the 30-06 operating in the same velocity range and same weight of rifle.

The reason that a muzzle brake works, and it does, is because it reduces the pressure at the muzzle. Instead of letting all of the gases exit the barrel from one hole, it dispurses throughout many, and in various directions and angles, depending on brand of muzzle brake. This does reduce felt recoil by reducing pressure.

So, to propel a similiar bullet of size and weight, at a similiar velocity, with a reduction in pressure, will result in less felt recoil, as well as muzzle blast. But, I think one can differentiate pretty easily between muzzle blast and felt recoil, especially if said person is wearing hearing protection. I'm not sure how someone could confuse those two. One hurts the shoulder, and one doesn't.

After rereading Burgess's post I see that he was also taking into account the rifling twist.
Thos. M Burgess wrote:
"Having both a Rem and Rigby to shoot one after the other settles things rather quickly.
There are 3 main components to recoil. Initial thrust, acceleration recoil, and rocket thrust when the propellant gases reach the air at the muzzle. You feel all three at once as a simple reaction. To this you can add counter rotation, the reaction counter the rifling twist, and in a right hand twist, 1:14 in the Rem and a faster burning powder to move a 400 gr. projectile to match the lazy old Rigby and the 1:16 twist I use for it makes the Rem. uncomfortable by comparison. Expln. Counter rotation- Rifle wants to spin in opposite direction to the rotation of the bullet. Most noticible when heavy bullets and fast powders are employed. Felt recoil along side face, sometimes bruises to match. Not really pronounced between the 2 rifles but If you have them to shoot a lot,you would notice the difference, and at 2375FPS for the both. A fat old Rigby at 16 twist can and often does print 325 through 410 grain bullets in the same group out to 100 and sometimes even to 150 yards. The Rem at 14 twist is a bit more finicky."

Would having a left hand twist not give you a little less of a slap on the side of the face?

Hart

Take a look at the Border Barrels website:

http://www.border-barrels.com/

And click on the "Kolbe Pmax" button at the top right of the page. The explanation of the physics shows how pressure and recoil are related. Interesting stuff.

jim dodd

Hart, et inter allia. I saw your post just as I was closing down to play my Balthasar role. Decided " they'll figure it out" and eventually that happened. Yes, a left hand twist would save the bruises to the jaw. I reckon that you have suspected that I chose the words I use and drop little seemingly unconnected tid bits in my posts for a reason. True. Kudos to you.
I had the fortune or misfortune to become acquainted with John Mutter who invented and patented the Pendleton streamline Muzzle brake, AKA the Pendleton De Kicker. I have about an inch of compressed correspondance with John. Between that and his regular visits to my shop I learned more than anyone would ever really care to know about recoil. Much of the information contrary to the accepted punditry in the shooting magazines. It did not make me what I would term an expert. Remington had a plan involving an attempt at market supremacy. They also had an excellent research establishment. Winchester was out of the chute with the .458, probably more to follow and they decided to spend loot on recoil reduction. They did all of their research on a lab basis. Experiments, run the math, and so on . Eventually they had enough material to patent and produce, in that order. Mutter had beat them to the patent by several months, using crude math and a lot of trial and error, and it worked. Remington was interested in buying his patent but first since it was a lot cheaper they wanted his best results on current for the times calibers including wild cats and Ackley's and Weatherbys. In order for him to experiment and get the most recoil reduction available for a given cartridge John needed better research tools. He received the prints for an accurate recoil meter. He also was told the type of film to employ, the camera and the shielding medium to photograph the exiting gasses through all those holes in the brake. Infra Red. Why? So you could see where the hot gases went, whether they actually reduced recoil etc. Simple and quite graphic. In time I actually got to where I would rather sit for a viewing of my mother's home movies. A cinematographer she wasn't. John's nemisis, his Moby Dick was the 458 Win Mag. Rapid twist, counter rotation of the rifle, Acceleration recoil and no matter what he did his recoil meter read the bad news, Without building a Cutts Comp looking thingy on the end of the barrel never over about 22% reduction. I asked him once if he really needed a barrel recoil lug, thinking that He might have achieved something, so he removed the boat glass behind the lug and found that his system was kinder to stocks. The recoil meter was sort of a sled viewed from a distance and it was used together with the camera in testing various innovations devised for new calibers. John came to me because he knew I had spent several years married to a tool and cutter grinder making weird tools for Govt. work and could usually show him some way for him to make the endless special tooling he required. ( And I had access to Military research as well as commercial) Winchester had a Workmans Comp court case to settle for an employee in the test firing Dept and that lead to Olin spending bucks on the medical effects of Felt recoil. Finding. The shock waves to the frontal area of the body are not good on you. Brakes can add to the effect.
So, Jack, right on. Velocity of recoil.
That " comfortable" remark bore fruit quicker than I thought it would. Question, If the 45/70 stabilises reasonably well in 18 to 22 twist using the 500 grain bullet, Why do you need one in 14 for something like the Rigby 45 cal on the .416 case? And have you ever wondered the effect on Helicopters from recoil? 3 million parts that 2 pilots are trying to herd in the same direction and hoping that that direction is where they need it to go and those M.G's shaking all those parts when they are fired?

Wow..... so I was actually right for once? heh

I did not read the article, but I'd bet dollars to donuts the 416 Rigby he shot was at least a good pound heavier then the 416 Rem, and perhaps had a better designed stock.

I can assure you that going to a larger case, and burning more powder, will increase recoil. I have an excellent example, I had a 35 whelen ackley that was re-chambered to a 350 Rigby. Same stock, barrel et all, only difference is a larger chamber, and burning 66gr varget to push a 250 gr 2700 fps vs previously 60 gr getting the job done. Recoil was definately increased. I can also attest to different powders having different recoil signatures, as 72 gr 4350 in the Rigby achieves the same 2700 fps, but recoil is much more unpleasant then the 66 gr Varget load.

If your 338 win mag has too much recoil, re-chambering to 338 ultramag isn't the solution!!!

Yeah, but......

There are several things that can change the character of recoil.

Take, for example, muzzle pressure. Higher muzzle pressure creates a larger rocket effect. Since the jet effect occurs after the bullet departs the barrel it logically creates more of a vectored thrust than a bullet accellerating from the case. In other words, the tip of the barrel, in a poorly balanced rifle, will rotate (recoil upwards) more (foot-lb for ft-lb).

Add to that the longer barrels employed by most high pressure chamberings, and the effect becomes more pronounced. Depending on stock and rifle design, I would expect more upward directed recoil the higher the muzzle pressure. FWIW, Dutch.

The gasses will escape in all directions equally. The upward (rotation) is due to the shooters shoulder. If a barrel and block were fixed such that the assembley had no moment arm, it would recoil straight back.

I agree with Paul H. A lower pressure using more powder will spread the acceleration over time making a perceived recoil (probably) feel less. The higher pressure would result in quicker acceleration for the projectile and higher escape velocity for the gasses. What is in must come out. If 120 grains of powder are in the case, 120 grains of gass will come out. Though lower in muzzle pressure, and lower escape velocity, due to the volume of escaping gass, the recoil (numbers) will be the same.
Perceived recoil is a completely different animal. See my thread on mercury recoil reducers in the big-bore section.

Didn't one of the gun scribes write an article a few years back on the "jet effect" of burning gasses? More specifically, he was comparing felt recoil.

If I recall correctly, he was comparing the Weatherby line of cartridges to other belted magnums.

From somebody's book I just read the rifling is the prime contributor to recoil. Bigger cases accelerate the same bullet faster and to a higher rotational speed over less time than a smaller case - given the same twist - and thus generate more recoil - heavier bullets have more contact area with the rifling and because of increase resistance generate more recoil - why tank barrels are smooth bored - far less recoil than if they were rifled. Some of the recoil is torgue or twist generated but the the bullet may do 2 full revolutions (1.5 inches for a 25 cal bullet) on its path down the barrel vs 2 ft or so of linear travel - why most of the recoil is back into your shoulder. Bigger cases also have more gas (mass) and this combined with the discharge velocity of the gas does contribute to recoil - but this is small in comparison to the rifling generated recoil - why a muzzle mounted brake can only reduce recoil so much by deflecting the gas rearward.

Just have to put in my ignorant 2 cents and expound on Paul H, Roger, et al.

A factor in felt recoil is related to the acceleration of the bullet over time (rifle weights being equal), and is not totally dependent on peak pressure. Acceleration (Gs) is velocity increase over time -- feet per second (velocity) per second. As the amount of time over which velocity increases occur, the lower the acceleration (recoil) is.

It was mentioned that an '06 recoils softer than a 308 when loaded to the same velocity. Why? Because the larger '06 case probably develops pressure more slowly resulting in velocity increase over a larger span of time. More time equals fewer Gs, and less resultant recoil on the shooter.

Acceleration attenuation is also why recoil pads work. Not only do they take away the painful sharp egdes and distribute pressure evenly, they also add a time delay to transferrence of energy from the rifle to the shooter. As the pad is squished it soaks up energy, causing a lower velocity increase to the shooter over a longer span of time. Eventually, that energy comes back out of the pad at a later time, also increasing the total time of velocity change. So, as one increases the number of (milli-) seconds by which velocity change is being divided, acceleration (recoil) is lessened.

Newton's "equal and opposite" law with mass thrown into the mix seems to undo the 'rocket' effect theory as a significant cause of recoil. The bullet gives significantly greater mass for the propellant and rifle to 'work' against than air at the end of the barrel ever will. If you see high-speed photos of bullets a few inches past the muzzle, the gases have always shot past the bullet indicating there is so much less mass in air for the gas (and rifle) to work against.

More bullet bearing surface and/or barrel twist may increase recoil because they change the pressure curve of the propellent, and thus the acceleration of the bullet and gun. Also, smooth bores develop more velocity because no energy is used up to impart rotation on the bullet, not to mention the rifling itself is a source of friction that causes energy to be lost through heat instead of energy being used for velocity.

My question is: given identical cartridges, gun weights and muzzle velocities, will a longer barreled rifle have less 'felt' recoil because the bullet reaches the target velocity over a longer distance / time?

blah, blah, blah, blah, blah....

[ 07-02-2003, 21:46: Message edited by: The Duh-merican ]