Choosing a Recoil Spring

CHOOSING A RECOIL SPRING

by
Donald Plunkett

A quick look at the latest Brownells catalog will show a bewildering selection of recoil springs for the 1911 pistol.  Listed by weight, they range all the way from seven to 26 pounds and come in straight and variable rates.  Why so many different springs for one pistol?  Which one is the best?  Understanding and choosing a recoil spring isn’t difficult, and it’s worth the trouble as the correct recoil spring is critical to the reliable operation of the pistol.

The recoil spring is the big spring that compresses under recoil and furnishes the force necessary to finish cycling the action when it returns to length.  Please note that, although it may be the largest spring in the firearm, the recoil spring is not the mainspring.  The mainspring is always the spring that powers the hammer or striker when the pistol fires.  Some mainsprings also perform other functions in some firearms designs, but they still provide the force behind the hammer or striker.

The recoil spring works by absorbing the recoil energy caused by the firing of a cartridge.  The spring stores the energy by compressing, and releases the energy by relaxing.  In order to compress, the spring has to work against some resistance.  Some resistance is provided by the mass of the pistol but the primary resistance is provided by the shooting hand.  Sufficient energy must be stored to allow the spring to complete the firing cycle as it relaxes.  The spring must also provide enough force to keep the action closed until the pressures in the barrel drop to a safe level.   A reduction in the available energy means a lighter spring is needed.

What reduces the energy?  Lighter bullets, lower muzzle velocities, compensators, and increased slide and barrel mass will all reduce the recoil energy.  Reduced resistance to the recoil will also reduce the amount of energy available to the spring.  Lightweight frames and a weak stance will cut down on the amount of energy the spring can store.  Allowing the wrist to flex freely under recoil— called “limp-wristing”— can actually cause malfunctions due to lack of spring energy.

What increases the available energy?  Heavier bullets, higher velocities, lighter slides, or a strong wrist and grip will all increase the available energy.

The recoil spring weight is measured at the full recoil compression.  A Government model, five inch barrel, 1911-A1 in full recoil has 1.625 inches of room left for the recoil spring.  It takes 18 pounds to compress an 18-pound recoil spring for a Government model to 1.625 inches.  A Commander length slide only leaves 1.125 inches in full recoil so an 18-pound Commander spring will require 18 pounds to compress it to 1.125 inches— the same spring weight but completely different springs.  The Officer’s model compresses its springs to 0.700 inches.  The maximum or “solid” compression length of a spring is the number of coils times the diameter of the wire.  If the solid compression length is longer than the room left for the recoil spring at full recoil, the spring won’t work.  A recoil spring for a Commander must have a solid compression length of less than 1.125 inches.  The shorter full recoil compression lengths also mean that the springs have to absorb the same amount of energy in a shorter distance.  A shorter slide requires a heavier spring to do the same work.  The spring rate is determined by the uncompressed or “free” length of the spring, the diameter of the wire, the number and spacing of the coils, and the construction material.  Colt lists their springs by the number of coils rather than by weight.

Most recoil springs are constant rate.  This means that for every inch of compression, the force required to compress the spring goes up by a fixed amount.  For example, one pound compresses the spring one inch, two pounds compresses it two inches and so on.  The force required to compress variable rate springs increases in a curve rather than at a straight rate.  It may only take eight ounces to compress a variable rate the first inch, then 18 for the second inch and 30 for the third.  The total force required to bring a 20-pound variable rate spring to full compression will be the same (20 pounds) as a 20-pound constant rate but the way it gets there is a little different.  The advantages to a variable rate recoil spring include the ability to smoothly handle lighter loads mixed in with full loads, easier unlocking, and smoother recoil.  One disadvantage to a variable rate is that, for a given weight, the variable rate will tend to unlock the action earlier than a constant rate spring; this may cause problems with heavy loads.

Recoil springs do need to be replaced periodically.  Most of the top 1911 gunsmiths recommend replacing the recoil spring every 2,000 to 5,000 rounds.  I have heard some other folks recommend replacement every 10,000 to 20,000 rounds.  I think I’d rather play it safe and change my springs out a bit more frequently.  According to the technicians at the W. C. Wolff company, Wolff springs of the correct weight for the application will go a minimum of 2,000 to 5,000 rounds before they need replacing.  A single spring used to replace a double spring set may require replacement in as little as 750 to 1,500 rounds.  It’s a good idea to replace the firing pin spring at the same time as the recoil spring.  Another method of determining when a recoil spring needs replacement is to buy two identical springs and compare them when you field-strip the pistol.  When the used spring is two coils shorter than the unused spring, replace it.

New springs will take a slight set immediately.  Wolff rates their spring weights with this in mind.  A 16-pound Wolff spring will be at 16 pounds after this initial set.  Further reduction in weight will occur much more gradually.

Synthetic washers or buffers that fit between the recoil spring and the recoil spring guide rod are great.  The first commercially available were the Shok-Buffs made by Bill Wilson.  Buffers keep the frame from battering under full recoil and actually cushion felt recoil a bit.  Buffers also come apart without warning leaving little bits of plastic or fiber inside the pistol; that’s just asking for a jam and is unacceptable in a carry gun.  One solution is to replace the buffers before they have a chance to wear out.  A better solution is to put the buffer in for practice sessions and remove it for carry.  The synthetic buffers can provide some indication that your recoil spring is too light.  If the buffer is showing signs that the slide is hitting it with some force, a new or heavier spring may be indicated.

Another item that works like the synthetic buffers is a recoil guide rod with a spring and plunger assembly built in.  A set of dual nested recoil springs is used in some pistols for a similar effect.

The best way to see which recoil spring weight will give the best results in a pistol is to buy a series of springs of different weights and test them.  Always make sure the pistol is in good working order before trying different spring rates.  Other problems with the pistol can mask or imitate malfunctions caused by an incorrect spring rate.  The best rule of thumb is to use the heaviest spring that gives reliable functioning.  Remember that how you hold the pistol will have a big impact on how well a given weight of spring will work.  A firm Weaver stance will allow a much heavier spring weight to function well than the offhand stance will.  Also remember that a spring that works well with one load may not work as well with a heavier or lighter load.  Match the spring to the ammo.  Adding compensators or barrel weights will change the required spring weight.

Always start with the heavier springs and work down.  A too heavy spring is not as dangerous as one that’s too light.  Ejection is a good indication of how a particular spring weight is working.  If the empties are just dribbling out the ejection port, the spring is probably too heavy.  If the fired casings are sailing over the horizon, that’s a pretty good indication that the spring is too light.  With most 1911s an ejection pattern that lands one to two yards out is about right.  As the spring weight gets too heavy the slide will not come back far enough to eject the spent rounds resulting in stovepipes or even failures to eject.  The slide may also fail to come back far enough to pick up a new round, or engage the slide stop.  A very heavy recoil spring can cause the slide to close with excessive force.  Not only will this increase the wear on the pistol, it can induce slam-fires when the firing pin is flung forward.  A heavy-duty firing pin spring or even a lightweight firing pin are strongly indicated when a heavier than standard recoil spring is installed.  Very heavy recoil springs also make it difficult to manipulate the slide.

A too light spring will allow the frame and slide to batter under recoil.  Sometimes a light spring will also fail to engage the slide stop.  The excessive slide velocity will cause it to bounce past the slide stop without catching.  The biggest concern with a light spring is the slide unlocking too early while the chamber pressure is still high.  The first indication of early unlocking may be elongated firing pin indentations on the fired primers.  The cases may begin to bulge where they overhang the barrel feed throat.  At its worst, the case will actually burst allowing the hot gasses to pour out of the open action.  This situation is very dangerous.

Even when the pistol and load call for an extremely light recoil spring— as can be the case with compensated target guns— the light spring may cause some feed problems.  The spring just doesn’t have the oomph to handle a slightly oversize cartridge or a dirty chamber.

One other problem that may crop up is recoil spring binding.  If the spring weight is correct and the spring is for some reason binding in its raceway, a full length guide rod can help ameliorate the problem.  I have never had a problem with spring bind in a quality 1911 with a quality spring so I am disinclined to use full length guide rods and instead try to isolate the cause of the binding.

What are the “standard” spring weights?  The military specifications for the M1911 .45 caliber, 230 grain cartridge call for 855 fps plus or minus 25 fps measured at 25 feet from the muzzle.  The last field manuals list a muzzle velocity of 830 fps.  The issue springs were 16 pounds which may be a bit light for full loads.  American factory loads dropped in velocity to avoid battering the pistols.  A few years ago, commercial ball chronographed at 800 to 820 fps and the generics chronographed at 750 to 800 fps.  Foreign ball was still at 850 fps.  Current catalogs list 185 grain target loads at 770 fps and hardball 230 grain loads at 845 fps.

The five inch Colt Government model and Springfield 1911-A1 in .45 ACP are standard with a 16-pound spring.  If full loads are to be used, a 17 or 18-pound spring reduces wear and improves feeding.  For someone who uses full loads exclusively and shoots from a firm stance, a 20 or even 22-pound spring may be better.  An 18.5-pound spring is a bit more forgiving of a looser grip and that’s what I use in my carry guns.  I will generally use a pound or two more weight with a variable rate spring.

The Gold Cup comes with both a 16-pound (32 coils) spring, and a 14-pound (28 coils) spring for target loads.  The 14-pound spring is also standard for the 9mm, .38 Super, and the .22 lr Ace and conversions.  The 10mm Delta Elite uses a second inner spring in addition to the standard 16-pounder.  The .40 S & W uses a 19-pound spring.

A 20-pound spring is standard in the 4.5 inch Commander in .45 ACP.  The Commander in .38 Super or 9mm uses a 16-pound spring.  The Officer’s model comes with a pair of nested springs that run 22 pounds.  Two extra pounds of spring weight for either of these pistols is a good idea for heavier (230 grains at 860 fps) loads.

The technicians at Wolff’s or Brownells can help you pick the exact spring for any pistol or purpose.  Choosing a workable spring is easy and finding the perfect spring only takes a little more effort.  Recoil springs are inexpensive but they are critical to the function and longevity of your pistol and certainly deserve some thought.

Brownells, Inc.

200 South Front Street
Montezuma, IA  50171-1000
Phone:  515-623-5401
Fax:  515-623-3896
www.brownells.com

W. C. Wolff Company

P.O. Box 458, Dept. 100
Newtown Square, PA 19073-0458
Phone:  610-359-9600
Fax:  610-359-9496
www.gunsprings.com

Wilson Combat Handguns

2234 CR 719
PO Box 578
Berryville, AR 72616
Phone:  800-955-4856
Fax:  870-545-3310
www.wilsoncombat.com