Spring Weight Adjustments

[SlowFuse]

Just a thought i've had, searching didn't really give much insight on adjusting spring weights.

The scenario is when you have an auto, we'll say a Glock for example since it seems common to change spring weights on them for lighter or heavier loads. If you have a slide that has cuts that have removed material like we see are getting more popular lately do you change the spring weight? Is the removed weight enough to really affect the mass of the slide and the timing or how fast it unlocks and cycles? This could also go the other way, if you have a pistol slide with an optic cut and you add an RMR or something similar that is adding weight, should spring weight be something that's considered for optimal performance?

 

[JTQ]

Probably.

Using the Glock example, the early Gen 4 9mm Glocks, the G17/G19 had ejection issues as the Gen 4 was designed as a fix for the G22/G23, and some of the stuff carried over to the 9mm version, such as a stiffer recoil spring. Glock quickly figured out the Gen 4 G17/G19 springs were too stiff (probably the same spring that was in the G22/G23) and corrected the issue.

On the other hand, the G20/G21 uses a heavier slide (and I'll assume recoil spring) and is a bigger gun, than the G17/G22, while in the 1911, all slides, whether .45 Auto, 10mm, .38 Super, .40 S&W, 9mm, etc., all weigh the same. Spring weights are what allows them to function. Of course one could expect a 1911, with a recoil spring in the higher range for a 9mm, with low powered, 115gr training ammo, with grease as the lube, on a cold day, to have function issues.

Nothing is in a vacuum. Every change you make probably affects how your gun functions.

 

[cougar1717]

There is a factor of safety. Most of the time shooters want to reduce that factor in competitive use. Lighter loads plus lighter springs can have an advantage. But don't forget the need to tune the magazine springs - the ammo has to be there for the slide to pick it up!

 

[JohnKSa]

If you want to significantly alter either the muzzle momentum or the weight of the recoiling mass in a recoil-operated autoloading pistol then you can try to compensate for the predictable problems that will result from trying to operate the gun outside of its design parameters by altering the operating weight of the recoil spring.

If the gun is intended for self-defense, that doesn't seem like a great strategy, IMO. It would be way better to purchase a reliable gun that is designed to provide the muzzle momentum that you feel is desirable.

If the gun is intended for competition for for other recreational purposes, then experiment away until you're satisfied with the reliability of the result.

This could also go the other way, if you have a pistol slide with an optic cut and you add an RMR or something similar that is adding weight, should spring weight be something that's considered for optimal performance?

You can weigh the slide/barrel/recoil spring assembly before and after installing the sight to see if the added weight is significant.

My guess is that the difference is much less than you might expect as a decent amount of metal must be removed for the optics cut. Some of that weight is replaced by the weight of the sight, and I'll bet the overall difference with a sight installed is quite small.

 

[SlowFuse]

My guess is that the difference is much less than you might expect as a decent amount of metal must be removed for the optics cut. Some of that weight is replaced by the weight of the sight, and I'll bet the overall difference with a sight installed is quite small.

I'll bet you're right, I just looked at the Trijicon and it weighs just over one ounce. The metal removed for the optic cut i'm guessing would be similar to that weight so the slide would end up being pretty much the same.

The main reason i'm thinking about this was because I was going to start making increasingly lighter (sounds odd, working down on load data) reloads in a G17 down to a power level that creates failure in regard to cycling reliably, then bump it back up a little. My slide has cuts near the front that removed material. So I wasn't sure if it would cycle faster because of the lighter slide weight (although probably not a significant difference as mentioned) and would negate the theory of reducing spring weight by a couple pounds for the lighter loads. Probably over thinking things, I see ISMI makes 15, 13 and 11 lb. reduced power springs so I just need to get a couple of those and try it... If they don't function its not that big of a loss.

 

[film495]

probably depends on percentage of weight to the weight of the original slide before modification if it would matter much. if you're mucking around with it and testing, at some point adding weight to the slide would also cause it to fail, but I bet it would take a significantly larger change than adding a sight or some nominal change.

 

[tarosean]

The scenario is when you have an auto, we'll say a Glock for example since it seems common to change spring weights on them for lighter or heavier loads.

In my opinion Glocks are oversprung out the box.
More specifically I have a G34g4 with RMR that I used for competition. I run a tungsten guide rod (g3 conversion) with 13lb recoil springs. This speeds the slide up alowing it to shoot flatter vs stock 17# *Keep in mind that I am aiming for fast splits and not longevity with that gun.

 

[JohnKSa]

In my opinion Glocks are oversprung out the box.

As long as the ammo provides enough momentum to run the recoil spring a little extra spring is nice. That extra oomph when stripping the round from the mag and chambering can be the difference between function and malfunction. It's probably true that recoil springs on most guns are heavier than they absolutely need to be--that provides a certain margin to compensate for various issues that might otherwise cause the gun to malfunction.

 

[JTQ]

With the understanding that there is a difference between reliability and durability (ignoring shoot-ability, ammo costs, etc.) ...

As long as the ammo provides enough momentum to run the recoil spring a little extra spring is nice. That extra oomph when stripping the round from the mag and chambering can be the difference between function and malfunction. It's probably true that recoil springs on most guns are heavier than they absolutely need to be--that provides a certain margin to compensate for various issues that might otherwise cause the gun to malfunction.

I wonder if the .40 S&W gives some reliability advantage over 9mm in some conditions due to the increased energy the round produces and the ability to drive the slide in adverse conditions.

 

[JohnKSa]

The ammo only drives the slide backwards--that has an impact on unlocking, extraction and ejection. The main functioning aspects in terms of getting the gun ready to fire the next round (stripping the round, chambering it, driving the slide/barrel assembly into lockup) are all performed by the recoil spring.

 

[JTQ]

The ammo only drives the slide backwards--that has an impact on unlocking, extraction and ejection. The main functioning aspects in terms of getting the gun ready to fire the next round (stripping the round, chambering it, driving the slide/barrel assembly into lockup) are all performed by the recoil spring.

Because you have stronger recoil with .40 S&W, you can use a stronger recoil spring to return the gun to battery.

The light recoil of a 9mm limits the strength of a recoil spring that will allow the gun to unlock, extract, and eject. Upping the power of the round allows a stronger recoil spring to overcome crud or anything else that may slow a slides return to battery.

 

[JohnKSa]

The main functioning aspects in terms of getting the gun ready to fire the next round (stripping the round, chambering it, driving the slide/barrel assembly into lockup) are all performed by the recoil spring.

Because you have stronger recoil with .40 S&W, you can use a stronger recoil spring to return the gun to battery.

Both of these statements are true.

It's important to note that just because the manufacturer can install a stronger spring doesn't mean they will. Glock has been known (at various times in the history of their guns) to use the same springs for their equivalent sized .40 & 9mm pistols, for example. There are a number of reasons they might not put a heavier spring in.

• Increased parts commonality.
  
• Users don't like strong recoil springs.
• The stronger spring slams the slide forward harder resulting in additional wear to parts.
• In extreme situations, a spring can push the slide forward so fast that it doesn't pick up a round.
• A stronger spring makes grip issues more likely to result in malfunctions.

Finally, feeding a larger, heavier round, requires more force from the spring, so you might increase the spring force for the heavier caliber and get no overall change in how the system operates.