The Effect of Recoil By Wayne van Zwoll

The Effect of RECOIL

By Wayne van Zwoll

It’s in the math. But a rifle’s kick is like love: numbers aren’t what you feel. Or remember.

Careful zeroing requires more shooting than you'll do afield. Your rifle, load and position should make it a pleasant exercise!

He was an onlooker. The range was all but empty. “Could I try that?” I had one cartridge left and handed it to him, with the rifle. Quickly he thumbed the cigar-size round onto the follower and stepped to a bench.

“Best stand,” I said, “so you can flex a little.” He nodded vacantly, hoisted the CZ and pulled the trigger. At the concussive blast, his shoulder convulsed. The muzzle flipped skyward as he stumbled back then fell on his fanny, hard. The rifle, now a 10-pound baton, sailed end-over-end into the grass beyond.

I retrieved it while the fellow picked himself up.

“Good golly!” he gasped. No harm to anything but his pride, it seemed. My .505 Gibbs had nary a scratch.

Isaac Newton described recoil when he figured out that for every action there’s an equal, opposite reaction. You can calculate the kinetic energy of recoil with this formula: KE = MV2 / GC, in which M is the rifle’s mass and V its velocity. GC is a gravitational constant for earth: 64.32.

Now, mass and weight aren’t the same. Mass is the measure of an object’s inertia. The theory of relativity states that two objects have equal mass if the same force gives them equal acceleration. Using gravity as the force, you can equate mass with weight – a measure of the force by which gravity draws an object to earth. Rifles all respond much the same way to gravity, so for most purposes, their mass equals their weight.

To get rifle velocity, you must crunch numbers. The formula: MV = bullet weight (grs.) / 7000 x bullet velocity (fps) + powder weight (grs.) / 7000 x powder gas velocity (fps).

Powder and its gas figure in because, like a bullet. they are “ejecta” and contribute to recoil. Gas velocity varies; but Art Alphin, in his A-Square handloading manual, claimed 5,200 fps is a useful average. The “7000” denominators simply convert grains to pounds so units make sense in the end.

For a 180-grain bullet sent at 3,000 fps by 70 grains of powder in an 8½-pound .300 Winchester, you’d calculate recoil this way: MV = 180 / 7000 x 3000 + 70 / 7000 x 5200. That simplifies to (77.143 + 52) / 8.5 = V = 15.19 fps. Then you activate the first formula: MV2 / GC = KE. The result: 8.5 (15.19)2 / 64.32 = 30.49 ft-lbs of recoil.

Obviously, a lighter rifle delivers higher rifle velocity, and more recoil. A 6-pound .30-06 firing a 180-grain bullet at 2,700 fps hits you with 30.26 ft-lbs of recoil – about the same as our 8½-pound .300.

Kinetic energy is not “kick.” What we feel as kick can vary significantly among rifles delivering the same level of recoil in ft-lbs. One reason: A faster bullet dumps the recoil quicker, contributing to rifle “slap.” It’s why some shooters describe the recoil of big-bore double rifles as a “push.” The bullet spends more time exiting, which dispenses the thrust less violently. MV for a 405-grain bullet clocking 1,350 fps from a .45-70 is essentially equal to that for a 200-grain bullet leaving a .30-06 at a frothy 2,730 fps. But in same-weight rifles, the ’06 load has the sharper kick. Bullet launch and recoil are quicker.

Felt recoil also depends on other variables. Stock design is one. A butt-stock of proper length will snug naturally into your shoulder; a short stock coming loosely to cheek has a running start and hits your clavicle instead of pushing it. If you push your left fist into your right shoulder, there’s no pain, no matter how hard you press. Now, hold that left fist in front of you and bring it sharply into your right shoulder…

Butt shape, size and material affect the kick you feel. Curved steel butts on 18th-century American muzzle-loaders cradled the ball of the shoulder. The toe of such a stock digs you uncomfortably in recoil if it’s inside that bulge, where modern rifles are held. A slight radius still makes sense, as does a pad with a generous “footprint” to spread the thrust. While a checkered Neidner or skeleton plate is elegant, that steel can maul your shoulder. The best pads, like Pachmayr’s Decelerator, look good on walnut and don’t harden and crumble with age as did early rubber. A soft butt-pad grabs your shoulder – and the ground if you lean your rifle against a tree. It also protects the stock from water damage better than does steel, as it keeps the wood farther off wet surfaces.

The stock’s comb must support your face without digging into it. Sharp combs with lots of drop (slope down toward the heel) hit you like a hatchet. The forward-sloping comb of the Weatherby Mark V may not appeal to traditionalists, but it does “shoot away” from your face, mitigating felt recoil. Cast-off, a custom option that “bends” the comb to better align your eye with the sight, can also reduce comb bite. Recoil mitigation in double rifles is especially difficult, as the barrels drive back off-axis to breech and butt-stock. The rifle’s pivoting action, if slight compared to the rearward thrust, slows a following shot.

Some butt-stocks house hydraulics, mercury capsules or springs. The mercury device in Blaser’s R93 trims the recoil of a .375 to the level of a .30-06. It even defangs the ferocious .500 Jeffery.

The stock’s wrist and forend should fit comfortably in your hands, to add control and help absorb recoil. Svelte profiles that make for quick pointing offer little “grip” to counter kick. But a stock too thick is slow and hard to steer. Checkering, rough texture and new soft finishes keep sweat, rain and snow from greasing your grasp.

As Mama told me, you can’t always have everything. A slim, exquisitely balanced Mauser in my rack is quick as a grouse gun. The trigger breaks like a delicate icicle; 500-grain solids print walnut-size groups. In recoil, alas, this .458 is lightning on skids, its smooth walnut slipping my hands. After a couple of shots my temples throb and my jaw goes numb. I live in fear of this mule-hoofed beast, but haven’t the heart to sell it.

Muzzle brakes trim recoil by reducing jet effect at the muzzle. The brake’s perforations bleed gas so it doesn’t all erupt at the bullet’s exit. The size, number, angle and placement of brake ports determine its net effect. Some brakes are big and ugly. Some, like those from Lex Webernick of Rifles, Inc., are slim and less ugly. Webernick’s barreldiameter brakes are so well fitted you must look closely to see a union. Designing them, he used a decibel-measuring device to make them as quiet as possible. Tiny vents angled forward mitigate recoil without ratcheting up the noise.

Ah, noise. Even the best brakes are noisy, and blast from the most aggressive causes concrete to crumble. Ear protection is your friend at the bench, but not when trying to hear game or whispered signals from your PH. Fired prone, a braked rifle can also unleash a blizzard of dust or powder snow, obscuring the target. And a brake increases barrel length a couple of inches without hiking bullet velocity. Solution: Use a brake in practice, then replace it with an unvented sleeve afield. Check to ensure point of impact is the same for both. You won’t feel the rifle’s kick when firing once or twice at game!

A suppressor tames blast and recoil. In South Africa a few years ago, a suppressed Remington in .375 H&H shot well for a young, slightly-built lass who loathed to carry it but fired it with aplomb. I’ve

This group shows the fine accuracy of a Quarter-Minute Magnum rifle and its .300 Win. Mag. load -- also marksmanship spared flinch-inducing kick!

found suppressors helpful not only for the first shot, but in speeding a second. The rifle doesn’t bounce as far off target, move my body as much or, prone, erase the sight picture with debris. Suppressors are costly and bulbous, though, and add otherwise-nonfunctional inches to rifles. In the U.S. and elsewhere, they’re demonized as “silencers” and subject to all manner of restrictions, licensing and fees.

Felt recoil is also a function of your shooting position. Recoil hurts most when

Quick handling in close cover can save you. Wayne's Montana rifle in .375 H&H Magnum combines power and agility with manageable recoil.

Practice from field positions at realistic ranges prepares you for the hunt, and will show you if you're flinching at the prospect of recoil. Though a "light" cartridge for some plains game, the .243 is civil in recoil. Result: tight groups -- and more hits in the vitals.

you’re prone and at a bench, as your torso can’t rock with the kick. Shooting uphill prone can also bloody your brow with the scope. On the bench, drape folded bath towels over your shoulder to deaden kick. Place a thin slab of foam padding under your right elbow. Before refining your zero, fire from prone and sitting to ensure you have adequate eye relief. Your brow will be nearest the scope then, and hard to pull back from the lens. Better to move the scope ahead a bit. It’s easy to slide your face forward when catching fast aim offhand.

The real problem with recoil isn’t the jab you feel; it’s the anticipation of another. When next you pressure the trigger to the break point, you’ll consider the violence to come. Maybe you’ll shut your eyes and yank the trigger. But even without such idiocy, involuntary tensing of muscles can send the bullet off course… The striker is poised to fall. Oh my, did that last shot hurt! Yikes! It’s gonna git me again! Now! Oh, golly! NOW!

On a recoil tolerance scale of Gun-shy to Godzilla, I’m a notch above Wimp, keenly aware when I pull triggers that, save for a slip of rubber, all that lies between my clavicle and an aspirin-bottle load of IMR 4350 are brass, steel and hardwood. Might as well volunteer my body as a crash barrier for seat belt trials…

Flinching is a hard habit to unlearn. Better to use a rifle that, by virtue of its load, weight and stock dimensions, doesn’t intimidate you.

When your crosswire is on an animal, you can ill afford to fear the shot.