Can we talk about 1911 recoil springs ?

[oldbenn]

I have a variety of 1911 recoil springs that have been acquired over the years. The only 1911 pistol I have at present is a Mod 1969 National Match Colt (45acp, of course). I notice that some have 32 coils, some 26 and some 28 coils. I have crafted a set up to measure the resistance (weight) of the springs to within one or two pounds. Since I do not think the National Match Colt was designed to continuously fire hard ball ammo, I want to establish some limits regarding the pounding this nice shooting pistol is subject too by selecting the correct spring that will also give reliable function. I've been wondering, . . . . . How much space is there within these 1911's for the compression of the recoil spring ?? A 32 coil spring (regardless of the weight in pounds) would certainly take up more space than a 26 coil spring. When we purchase an 18 lb. spring, does that mean 18 lb. FULLY COMPRESSED ?? How many coils in a 18 lb. spring ?? Is there space enough for a 36 coil spring for example. Like to hear some thoughts on this.

 

[RON in PA]

Never heard or read discussions about 1911 recoil springs refer to number of coils. The poundage of the springs has always been the topic of discussion with 16 pounds the normal for shooting the usual 230 grain ball ammo. Weaker poundage used with light target loads.

 

[CZ9shooter]

I too am curious as to how a recoil spring's "weight" is actually measured. I come from a motorsports background where springs used in suspension components are expressed as a rate. Pounds per inch, kilograms per millimeter, etc. Progressive springs are often described using two rates, the minimum and the maximum.

One single number tells me next to nothing. Fully at rest? Fully compressed? At some amount of preload?

 

[Walkalong]

A 32 coil spring (regardless of the weight in pounds) would certainly take up more space than a 26 coil spring.

Assuming the same gauge/wire diameter, yes.

 

[Cemetery21]

I also made a spring measuring device several years ago. I don't recall the distance, but I was told the weight was measured at compression (the compressed length with the slide locked back). As far as spring weight selection, I just try springs with my preferred load and settle on the one that ejects a few feet and locks back.
You can test for spring bind by placing strips of masking tape on the slide and frame, With no spring in the pistol, hold the slide all the way back and mark a line on both pieces of tape. Then, put in the spring and bushing and the slide should open to the same mark if there is no spring binding/stacking. Of course, the spring guide should be in the pistol both times. I just leave the bushing out to mark the line. The unbound spring will hold the spring guide in place.

 

[harrygunner]

Interestingly, 1911 recoil spring weight is not the spring constant for Hooke's law. It's the pounds of force the spring presents when the slide is locked back.

The coil count/wire diameter needs to be correct to allow the slide to move back its full length. A bad combination during recoil can break the barrel bushing

For example, cutting a spring meant for a Government length 1911 to fit a Commander length 1911 will cause trouble in the shorter gun.

I did a quick calculation of the force on the barrel bushing if the recoil spring "bottoms out" or snags during recoil and it's of the order of ~1000 pounds.

 

[Skylerbone]

I did a quick calculation of the force on the barrel bushing if the recoil spring "bottoms out" or snags during recoil and it's of the order of ~1000 pounds.

I’m not good with math, but the recoil energy of a 1911 with typical loads is less than 8 ft lbs. As for available room for the spring itself, in-spec a government model should have 1.625” for the fully compressed spring. If you know diameter and coil count you could find your figure. I will agree that compression is not a good thing.

Spring rate on a standard 1911 recoil spring is linear, thus the first inch of compression will add the same force as the second or third. Why some have more coils than others will be related to wire diameter but no matter the count it must not exceed the allotted space. Therefore a 30 coil spring of thinner gauge could indeed occupy the same space as a heavier gauge 28 coil spring.

 

[harrygunner]

It's a simple physics calculation. I'm sure experiences can be found where the bottom front part of a 1911 slide is broken or the bottom of barrel bushings are broken with the whole spring assembly flying out. If you do the calculation properly, you can see why that can happen.

Edit: Wanted to add the Hooke's spring rate of a typical Government length 1911 in .45 ACP is around 3 lbf/in. One can use whatever numbers they like. For example, if the uncompressed length of the recoil spring is 6.5" and its compressed length is 1.63", the spring rate is about 3.3 lbf/in. 16/(6.5 - 1.63)

 

[someguy2800]

Your trying to use math for something where it just isn’t needed. Buy a set recoil springs such as the ones Nick Taylor sells or order the springs you have from heavy to light. Put the heaviest spring in it and shoot it with your load. Note where the brass falls. If it’s falling on your arm or at your feet the spring is too heavy. Work down till the brass is falling 3 or 4 feet away. Likewise if the brass is flying 6 or 8 feet away the spring is too light for your load.

 

[Col. Harrumph]

A decent general education about springs can be found on Wikipedia. Search for "Hooke's law."

 

[ArchAngelCD]

Program no expert but I don't think the number if coils will equate how much resistance the spring exerts. Difference in spring metal and tempering will change weight vs number of coils.

if you want to find the best spring weight for ammo you're shooting but a service springs from Wolff Gunsprings which comes with a variety of spring weights and change them out until you find the one that works best with your chosen ammo.
https://www.gunsprings.com/COLT/1911 GOV'T PISTOL/cID1/mID1/dID1

 

[Winkman822]

As another alternative if unsure what recoil spring to get, a call to the fine folks at Wilson Combat is always enlightening. They have numerous different spring weights and standard round coil and flat coil springs. The latter purport to have slightly longer service life. I for one cannot speak to the veracity of that claim as I prefer conventional springs in my 1911s. I use a run of the mill 16lb Wilson Combat spring in my 5" full size guns and a 22lb Wilson Combat spring in my compact 4" - 4.25" guns. Never a hiccup with this system except when the springs are ready for changing. At that point I'll occasionally have issues with feeding and ejection as the slide doesn't have enough dwell time when cycled fully rearward during firing before it starts returning to battery. Most common issue is a stovepipe type stoppage. If you have a full size gun and are worried about battering on the frame, Shok-buffs are an option, but I've seen where these cause issues with reliability, and if you're not militant about changing them every 250-300 rounds, they break apart and the bits gunk up the inner workings of the gun causing additional stoppages.

 

[wv109323]

Spring designations for the 1911 are not the same as those of mechanical engineers. The poundage is the force it takes to compress the recoil spring to the length of full compression in the 1911. That dimension,iirc, is 1 5/8" or thereabouts. The design does not allow the coils to fully collapse against each other.
The type of steel ,number of coils,and wire thickness will determine poundage given the same free length. As noted for ball ammo with a 5" slide that poundage is 16 lbs. The poundage of the recoil spring is not the only controlling factor in slide rearward velocity. Your load will determine your correct spring weight. You need a spring weight that will barely lock the slide back on the last round.
Your pistol may have a lighten slide. The slide under the extractor is removed. Can you see the extractor through the bottom of the slide. I would not feed thosee pistols with a continuous diet of hardball.

 

[someguy2800]

The hammer spring and the shape of the firing pin retaining plate also have an effect on the slide velocity.

A wise friend of mind used to tell me, “don’t estimate what you can calculate, and don’t calculate what you can validate.” Meaning it’s foolish to try to guess or calculate a solution to something that is easily tested.

 

[CZ9shooter]

meaning it’s foolish to try to guess or calculate a solution to something that is easily tested.

That may be true, but some of us are just plain nerdy. Meaning we like to have all the information we can possibly get our hands on. Even if it is inconsequential.

 

[GRIZ22]

1911 Tuner gave everyone a good education on recoil springs a few years ago. I can't find the thread now. These are a few things I remember from that.

1. John Browning did not specify a weight for the recoil spring. He specified a certain type and diameter of spring wire, number of coils, and free length. That works out to 16 lbs or whatever it is.

2. I don't think that even though Billy Bob is a USPSA Grandmaster and swaps out springs that makes him anywhere near the firearms genius John Browning waa.

3. Back in the 70s, IIRC, when they were the only 1911 show in town, Colt listed the same part number for a Government Model or Gold Cup recoil spring.

4. The only function of the recoil spring is to push the slide back into battery stripping off a fresh round for the chamber in the process. People have fired 1911s without a recoil spring.

5. Using a heavier recoil spring for hot loads really doesn't "save" your gun. What it will do is slam your slide forward way too hard putting uneeded stresses on your gun.

6. In relation to what someone else said here and #5 above all the springs have to be in tune with one another. That's the way the gun was designed. Same thing for other semiautomatics. I've never seen anyone suggest stronger recoil springs for a Garand.

 

[Skylerbone]

1. Firstly, by Browning’s math it was 14 lbs. and that was before manufacturers began heavily radiusing the firing pin stop.

2. Swapping out springs to match load is something Browning would absolutely agree with; after all he specified the specific gauge and coil count to accommodate 1 specific load the military would be using.

3. Gold Cups ship with 2 recoil springs, was one designated for reduced power loads.

4. What Tuner wished to espouse about its function does not for fact make. Sure you can fire a 1911 without the spring, but that is not the only benefit- something Browning surely knew.

5. Thus the milder radius of the original FPS.

6. Well the Garand isn’t offered in dozens of configurations/calibers and it’s gas operated. What you do see ar ARs with 6 or 7 gas lengths, different length buffer springs, different weight buffers, and tunable gas blocks. All of that to accommodate different configurations.

 

[Walkalong]

A bone stock 5" 1911 will fire anything from full power 230 Gr down to almost mouse fart level and still function with a 16 Lb recoil spring.

When you start changing slide weights adding comps, etc, etc, it changes things and a different spring may be needed.

But I agree, people way overthink 1911 recoil springs.

 

[harrygunner]

I agree that the significance of the recoil spring in a 1911 has been overblown in the 'net. It's there to return the slide in place for the next shot.

Recoil springs slow slides in recoil. But their effect on slide speed is diminished by the fact that speed reduction goes as the square root of increases in spring weight. The frame's abutment area, where the lower barrel lug impacts, was designed to handle the job of stopping rearward slide movement.

I'm of the opinion, too strong a recoil spring can lead to magazine feeding issues. On the other hand, a flat bottom firing pin stop changes the shape of the energy exchange curve to the hammer mainspring. The shape change improves magazine feed since that has the slide slowing sooner in the recoil cycle.

I deduced these opinions from calculations on the dynamics of the 1911. Mechanically, the 1911 is simple enough to model to first order. As 'CZ9shooter' said, nerds like to have information.

 

[oldbenn]

OLDBENN - Don't know who the thank the 'mostest' for all that's been posted here. Great job on my Question ! OB