How to check if the recoil spring binds

[1911Tuner]

Well...You can measure everything and add it all up to figure linear space available, and multiply the number of coils by a wire diameter and see if the spring takes up more than the available space....or just check to see that the slide travel is the same with and without the spring installed. I feel that the first method leaves too many variables to completely trust it, and prefer to check for the condition with the recoil system installed. YMMV

System installed, plug removed. Put a piece of tape in the inside of the *frame's* dust cover and pull the slide all the way to the rear. Hold it firmly, and use a straightedge to make a mark on the tape that aligns with the end of the slide.


Install the plug and pull the slide full rearward again...until the frame stops it...and hold it firmly. If the marks align, you're good to go. (At least, that's always been my experience.) If the front of the slide sits forward of the mark, the spring is stacked into coil bind, and it has to be trimmed. Cut one-half coil at a time until the marks align...and then clip another half-coil to make sure.

If, when you pull the slide rearward briskly, the sound of the slide and frame impacting is a dull "thud" or "crunch" the spring is stopping the slide instead of the impact surfaces of slide, guide flange, and frame rails. Bad JuJu. That causes the impact to be transferred to the spring plug and bushing...which throws stresses on the bushing lug's raceway in the slide. If the spring stops the slide as much as .050 inch before the impact surface does, the end of the slide can break at that thin area, and the slide is toast.

5-inch guns with standard recoil systems have ample room, and I've never seen one coil bind with any industry standard spring. Even ISMI springs, which used to come with 34 turns haven't presented a problem.

Guns shorter than 5 inches, or with reverse-plug recoil systems should be checked and double-checked...even if the spring is labeled for the gun in question. I've seen such spring dropped in without checking and work fine...and a couple have done permanent and expensive damage. The bushing will normally let go before destroying the slide...but not always.

[Spindly61]

Thank-you Tuner,
I have been following a few threads on this issue. A function check is always the final word. Measurements give you a ballpark to start in. Sometimes things get really deep in the forums, so deep I swear I hear an echo when I log on. lol.
Your views here express years of experience, I appreciate all you do here and hope all is well.
Rich

[1911Tuner]

Howdy Spindly. I tries. Lord knows I tries, but sometimes I gets a mite confused and don't write it so good. ;)

Another point that may need to be addressed...

I recently saw a post on the subject in which the adjustment was made based on whether the plug would compress the spring and allow the open end of the plug to touch the guide rod flange...and however many coils blocked the way were cut off. While that condition will assure that the spring isn't going to bind, it could also cost you a few coils unnecesarily.

Install the plug into its tunnel in the slide in the installed position and you can see how far the rear edge of the tunnel is from the open end of the plug. Just eyeballing my Springfield Mil-Spec looks like a good quarter-inch.
Since the rear face of the tunnel is the slide's impact/stop surface,
the spring wouldn't bind even if it was 4 coils too long to let the plug touch the guide flange, based on a .045 wire diameter. Commanders will show a little less difference, but the end of the plug still sits well within the rear of the tunnel.

[ArmscorBA]

1911 Tuner,
That was me! I have done this for ever! If your 1911 is broken in......Whats a couple of coils among friends? :p :lm:
Ivan
PS I use a 14# spring in my 45 acp 5" pistol, Cut it off and its about a 12#. Runs fine and not too much front end muzzel jump! ;)
Ivan

[1911Tuner]

Aha! So that's who it was! :D Honestly couldn't remember where I saw it.

Well...I can think of very few legitimate reasons to trim a spring, and more than a few reasons NOT to.

First off...Wilson's recoil springs, like ISMI's...leave a little extra for fine-tuning. 30 turns is spec. Wilson's are 32 turns across the board. The l;ast batch of ISMI springs that I bought were 30 turns, as per print spec.

For:

Fine tuning the slide's acceleration in recoil and return to battery in order to address a bolt-over base misfeed or the maddening incidence of "Jumping the Magazine." A too-light spring can contribute to either, just the same as a too-heavy spring can.

To relieve coil bind.

To fine-tune a spring to the particular load when a neither one of the standard springs will quite get there. This is pretty rare.

To make a spring for a Commander from a standard-length spring...which I actually prefer to buying one specifically made FOR a Commander...and cost isn't the primary reason for that practice.

Against:

Increased frame/slide impact in recoil, and the resulting flexing upward of the dust cover/spring tunnel (frame) that causes the slide to rebound harder...which sometimes contributes to bolt-over base issues, and "jumping"
the mag or the follower. Ever seen a frame crack at the junction of the tunnel and the rails? That's the result of the tunnel flexing when there isn't sufficient clearance between the top of the tunnel/dust cover and the bottom of the slide rail. The lighter the spring, the more it flexes, and the more clearance you need.

While a too-heavy spring can cause the bolt-over base misfeed problem, so can a too-light spring...but for different reasons.

Reduced velocity and momentum of the slide as it returns to battery, which makes everything involved in the feeding phase more critical. Extractor tension...Ramp geometry...(Frame and barrel ramp)...Chamber geometry and dimensions...(chamber finish, sizing, depth, headspace, etc.) Breechface condition...(Glassy smooth or with light toolmarks) In short, more speed and momentum enables the gun to be a lot more forgiving when things aren't just so. More forgiving of things like dirt and fouling and lack of lubrication, etc.

Better to have a longer, lighter spring than a short, heavy one. My standing advice when fine-tuning the number of coils for a particular load is that, if clipping two coils doesn't produce the desired results, to drop to the next lighter spring and start over rather than continuing to shorten the spring, because you'll soon reach a point that the gun is barely held in battery.
Even Colt limits it to about 29 turns for the "Softball" spring that they include with the Gold Cups. Best rule of thumb is to fine-tune for strong, positive ejection while maintaining all the in-battery preload that you can manaage, and that's done by leaving the spring as long as possible without stacking into coil bind.

I've rarely found a situation in which a standard pistol that can't be fine-tuned with spring rates outside of the 14-18 pound range, assuming any reasonable ammunition. Some reloaders assemble rounds that are so light, that less than 14 is required...but Wolff markets springs in one-pound increments all the way down to about 8 pounds. Others play with over-pressured rounds like the Super, and need a little more buffering, but that can usually be handled with the mainspring/FP stop radius and
an 18-20 pound spring without bringing on other troubles associated with
overspringing the slide so much. Toubles like excessive battering of the lower barrel lug and slidestop crosspin. Springs work in both directions.

Of course, pistols equipped with compensators often require much lighter springs due to the increased slide mass, but those are special cases. Likewise, pistols with heavy "bull" barrels occasionally require a slightly lighter spring...but not usually unless they're used in longslide pistols.

If, for some reason, you want or need less preload tension, it's probably best to go with one of the variable rate springs that are on the market than to cut a spring below its design parameters.

Hope this helps.

[John]

PS I use a 14# spring in my 45 acp 5" pistol, Cut it off and its about a 12#. Runs fine and not too much front end muzzel jump!
Ivan


Hmmm, Tuner correct me if I am wrong on this, but when you cut a spring, you do not reduce its weight rating, you increase it, n'est ce pas??

[1911Tuner]

Hmmm, Tuner correct me if I am wrong on this, but when you cut a spring, you do not reduce its weight rating, you increase it, n'est ce pas??


It does that only if you install it in a shorter space...as with a GM spring cut to Commander length. It increases the preload, and does a little to increase the compressed load...but the main increase comes from the amount of compression and the final compressed length. What it actually does is balance out the compressed load so that it will remain the same. In other words, a 32-coil GM spring cut down to 24 coils and installed in a Commander will still equal about 16 pounds or so in full compression...because in a Commander, the space available is reduced, which compresses the spring more and reduces the space between coils in full compression. If you compress a 16 pound spring until the coils are just before touching, the load will jump to about 17.5 or 18 pounds. They're rated at their nominal compressed length, not in full compression.

If you think of a spring as a straight piece of steel, you know that the shorter it is, the stiffer it is...but the increase from being cut shorter isn't linear the way it would be with a straight wire.

EDIT to add:

Cutting a 32-coil spring and installing it into the same space reduces the total compressed resistance because the spring doesn't reach the nominal compressed length...spacing between coils, and this cancels out the increase gained by shortening it.
If you inserted a spacer into the end of the spring plug that made up for the loss, the spring would be a little stronger in full compression than its rating.

Clear as mud...ain't it?

[Ash]

Hmmm, Tuner correct me if I am wrong on this, but when you cut a spring, you do not reduce its weight rating, you increase it, n'est ce pas??

cutting a spring increases the spring rate, but decreases the preload (if compressed into the same length space)

I dont know what manufacturers mean when they say "18#"... if they mean 18 pounds in the first inch of travel once INSTALLED, then cutting the spring probably would reduce the initial pressure.

if 18 pounds means 18 pounds per unit length (which is what a true spring rate is) then cutting the spring will always increase this number.

i may not know much about guns, but i do suspension tech on my motorcycle ;)

[ArmscorBA]

1911 Tuner,
You are going to Kill me! :p I use a cut down 6# spring in my Open Class Steel competion pistol. 38 super comp 115gr bullet 120 PF.
Ivan

[1911Tuner]

Ash...I guess the way to figure the spring rate is to measure the distance of the slide's travel and divide it into the maximum resistance as installed.
F'rinstance...3 inches of travel with an 18-pound maximum load gives up 6 pounds per inch.

You've brought up a good point, though...and thanks for doin' it.

Many people confuse the spring's rate with the load stated...or the rated maximum load. The two are related, but they're not the same.

And yes...SHortening the spring reduces the max load in a given tunnel length, but increases the RATE...the same as shortening a torsion bar or any other length of steel.

Example:

Take a flat spring and clamp one inch in a vise. Place your hand on the very end and deflect the spring two inches from a straight line. The resistance is
X pounds of force. Then, slip the spring deeper into the vise so that only 6 inches is protruding and delfect it two inches. The resistance is 2X pounds.
Then, deflect it one inch, and the resistance is back to X pounds...but if you suddenly release the spring, it will snap back straight faster than it would with 2 inches of deflection against a foot of spring protruding, even though the loaded resistance was about the same. The spring's RATE went up...but not the resistance....AND...it will be harder to deflect the short spring an inch then the long spring two inches because the spring's rate is effectively doubled. Yep...I know that it's leverage too...but that doesn't account for the higher rate.

Ivan...I try to avoid raceguns at every opportunity. They make me crazy enough in standard trim without askin' for headaches. :D

[robot1911]

Hey Johnny!! Don't kill Ivan too terribly. IMHO, that little 6# recoil spring is just about right for a compe'd Super with his stated load.

Bob

[1911Tuner]

Hey Johnny!! Don't kill Ivan too terribly. IMHO, that little 6# recoil spring is just about right for a compe'd Super with his stated load.

Bob

Nah. I don't do race and rooneyguns...

:lm:

[ArmscorBA]

1911 Tuner,
But they are so much fun!!!! I have two! :lm:
Ivan

[1911Tuner]

'Til daddy takes her T-Bird away... :D

I quit playin' with toy guns when I fired my first 1911 at about age 7.
No toys in my stable...but I do have about 40 weapons...if ya don't count the rifles and scatterguns.

:lh:

[ArmscorBA]

1911 Tuner,
Thats cold! :p :lm:
Ivan

[1911Tuner]

Yep...That's why they call me "Ice." :p

[ArmscorBA]

The IceMan! :p I like it! :lm:
Ivan

[1911Tuner]

Take note that the reasons that my friends sometimes call me "Ice" has nothing at all to do with Rap music. Zero...Zip...Nada...Goose eggs.

[ArmscorBA]

1911 Tuner,
I was thinking more along lines of the movie Top Gun. ! :p :lm:
Ivan

[1911Tuner]

Nah...Ain't never flew no fighter plane. It actually got started many years before Top Gun was even an idea in a producer's mind...and Tom Cruise probably hadn't started school.

Ivan...you okay in my book. If your travels ever take ya to the NC Piedmont, look me up. ;)

[ArmscorBA]

1911 Tuner,
Will do! Thanks! :D
Ivan