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lucas

Is it ok to shorten recoil springs

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My old spring is 9 pounds which is what the person who built the upper said it was. I purchased two new wolf 9 # springs and both are the same length but longer than the original. All springs tested around 9#. None of the new or old springs will allow the spring plug to bottom out. Both new springs have 37 coils and the old spring has 31 coils but visually only looks like it is 3 coils shorter. 

 

 

 While running bill drills, the front sight seemed to not want to get down in the back sight notch fast enough like before so I assumed spring was used up. Now with the new spring it comes down in the notch but likes to wobble around more in the notch than before. I wonder if that is because the new springs being longer are not allowing the spring plug to bottom out?

 

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According to the owner of Sprinco, it is not.  I was on the hunt for commander length recoil springs for for my CKARMS duty pistol.  Thankfully Wolff had a few to choose from. 

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New springs are usually slightly longer than used are. They take a "set" after being used the first time. They will shorten maybe 1/2 to 3/4 inch. I take it this is a 1911 you have. By not allowing the spring plug to bottom out, do you mean, not coil bound? You can compare the stacked length of the springs, by measuring the wire diameter and multiplying it by the number of coils.

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9 hours ago, GBertolet said:

New springs are usually slightly longer than used are. They take a "set" after being used the first time. They will shorten maybe 1/2 to 3/4 inch. I take it this is a 1911 you have. By not allowing the spring plug to bottom out, do you mean, not coil bound? You can compare the stacked length of the springs, by measuring the wire diameter and multiplying it by the number of coils.

The spring will not allow the plug to compress down the guide rod until it contacts the guide rod head. The recoil spring binds up and stops short. Is that coil bound?

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3 hours ago, lucas said:

The spring will not allow the plug to compress down the guide rod until it contacts the guide rod head. The recoil spring binds up and stops short. Is that coil bound?

 

Yes. you will have to trim it if it coil binds. Did the builder use a shock buff? A lot of guys cut a coil or two for the buff. also different brands of springs may have different coil diameters and free length.

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Thanks for the help everyone, got it now.

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Don't fire your gun anymore until you get this issue resolved. If your recoil spring is coil bound, you can break your barrel bushing, as it will be stopping the rearward movement of the slide, instead of the slide's dust cover.

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1 hour ago, GBertolet said:

Don't fire your gun anymore until you get this issue resolved. If your recoil spring is coil bound, you can break your barrel bushing, as it will be stopping the rearward movement of the slide, instead of the slide's dust cover.

 The two best ways I know to test spring binding is pushing the spring plug all the way down to see if it contacts the guide rod head and with guide rod in gun with out spring pulling slide all the back , marking on the dust cover ,then with spring seeing if it ends up to the mark.      It fails the first test but not the second test. I'm guessing but I think it might have something to do with the Dawson guide rod. My limited division 2011's in 40 and 45 all have longer spring plugs than the 9mm. I don't know if that's normal for 9 mm 2011's .

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Ive noticed that if i cut a spring because the load is too soft to cycle, i get to a point it becomes too short and it never cycles. Dont cut it.

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Cutting a spring does not make it lighter, only shorter. The only real reason to cut a spring is if you are having coil bind because it is too long. Buy the correct weight spring.

 

In fact, there is a theory that cutting coils off of a spring actually increases the weight (relative to the amount the spring is compressed)

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Adding or removing shok buff's does not change the available space for the recoil spring to compress. No need to cut a recoil spring if shok buff's are used. 

Cutting coils does not change the over all rating of any spring. For example, a 16 lb spring remains a 16 lb spring after cutting coils.

Cutting coils does increase the spring rate per inch. The overall rate such as 16 lbs is different than the spring rate per inch.

The overall rate of a compression spring is a function of each individual coil. For example a 16lb spring can be a few coils, as each coil needs 16lb to fully compress that coil. 

Since a spring that has had coils cut is now shorter, there is less dimension for the spring to go from zero to 16lbs. Thus the rate per inch increases. 

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On 9/12/2018 at 10:58 PM, xventurashooter said:

Adding or removing shok buff's does not change the available space for the recoil spring to compress. No need to cut a recoil spring if shok buff's are used. 

Cutting coils does not change the over all rating of any spring. For example, a 16 lb spring remains a 16 lb spring after cutting coils.

Cutting coils does increase the spring rate per inch. The overall rate such as 16 lbs is different than the spring rate per inch.

The overall rate of a compression spring is a function of each individual coil. For example a 16lb spring can be a few coils, as each coil needs 16lb to fully compress that coil. 

Since a spring that has had coils cut is now shorter, there is less dimension for the spring to go from zero to 16lbs. Thus the rate per inch increases. 

How does adding a .100 thick shock buff not decrease the space for a recoil spring? 

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On 9/9/2018 at 7:05 AM, GrumpyOne said:

Cutting a spring does not make it lighter, only shorter. The only real reason to cut a spring is if you are having coil bind because it is too long. Buy the correct weight spring.

 

In fact, there is a theory that cutting coils off of a spring actually increases the weight (relative to the amount the spring is compressed)

 

We cut springs all the time.  It works well as a tuning tool.

 

How a spring works when cut is no theory, it's physics.  When you remove coils from a given spring, that spring will indeed have a higher rate.  However, the free length is now different, the amount it is preloaded while the gun is in battery is different, and the amount that spring is compressed from free length at the end of the slide's stroke is different.  So while the rate is higher, in the end the forces the spring will output in the same gun are smaller because it is compressed less from its free length which accounts for more loss in force than the increase from the higher rate.  Not theory, physics.

Edited by theWacoKid

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27 minutes ago, ParaGunner said:

How does adding a .100 thick shock buff not decrease the space for a recoil spring? 

 

It adds an extra 0.1" of preload on the spring in battery.  It also shortens the slide's stroke (and thus deflection from the preloaded length) by 0.1".  But in the end, the fully compressed height of the spring at full travel is the same because the spring is still just compressed inside the reverse plug at full stroke in either case.

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19 minutes ago, theWacoKid said:

 

It adds an extra 0.1" of preload on the spring in battery.  It also shortens the slide's stroke (and thus deflection from the preloaded length) by 0.1".  But in the end, the fully compressed height of the spring at full travel is the same because the spring is still just compressed inside the reverse plug at full stroke in either case.

So if you had a recoil spring fit good and no coil stacking. Then added a shock buff and the spring then has the coil stacked from the addition of the buff. Wouldn't you say the buff decreased the area the spring operates,because of the coils now stacking from the shock buff?

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10 minutes ago, ParaGunner said:

So if you had a recoil spring fit good and no coil stacking. Then added a shock buff and the spring then has the coil stacked from the addition of the buff. Wouldn't you say the buff decreased the area the spring operates,because of the coils now stacking from the shock buff?

This isn't going to happen unless your buff reaches into the reverse plug.  Again, the final compressed height of the spring is the same with or without the buff.  That height is the internal length of the reverse plug.

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5 minutes ago, theWacoKid said:

This isn't going to happen unless your buff reaches into the reverse plug.  Again, the final compressed height of the spring is the same with or without the buff.  That height is the internal length of the reverse plug.

I've seen it happen, with a reverse plug and standard spring plug. Adding buffs does decrease the area for the recoil spring. Some even have used multiple buffs , like Brian Enos. I'm sure he had to clip a few coils.

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7 minutes ago, ParaGunner said:

I've seen it happen, with a reverse plug and standard spring plug. Adding buffs does decrease the area for the recoil spring. Some even have used multiple buffs , like Brian Enos. I'm sure he had to clip a few coils.

 

Are you sure? On my guns the spring is on top of the buff, the reverse plug stops when it hits the buff. The spring is contained inside of the plug. No number of buffs is going to change the amount of space inside of my reverse plug.

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