I have been working on guns for 50+ years now and I have never seen a discussion which I am about to undertake. If you know of other work on the relationship of spring in the modern semiautomatic handgun please share this with me. To make these guns run there must be a number of springs which come into play. Some springs like the mag release spring stand alone and do not affect the cycling of the handgun. These spring are not the subject of this discussion.
The springs we will be focusing on are: recoil spring, hammer spring, trigger return spring, firing pin spring, and mag spring, and how they effect the cycling of the handgun. Last we will look at how the springs inter react which each other.
First the hammer spring: This spring controls firing the primer, its main job. It also affects trigger pull, lock time and retarding the slide during firing. Many people in trying to improve and reduce the poundage of their trigger pull will look at this spring to the exclusion of all others. Some does and don’t with this approach.
Don’t cut a few coils of the spring to lighten the spring. This does not work well. Better is to replace the existing sprige with a lighter weight spring. You should check the accuracy of the gun before and after making this change. Light hits on a bullet primer can affect accuracy more than I originally thought. When working on this spring we must consider the firing pin recoil spring and the recoil spring, More on this later. R S
Part 2. The firing pin return spring. This spring should have one job and that is to retract the firing pin away form the breach during recoil. If the government and firearms manufactures had left the spring do it’s job we would not be covering it here. The government decided that if a firearm was dropped from a height it should not discharge. We are not talking of being dropped out of a belt holster. Any way the manufactures and their lawyers started adding safeties to their gun some IMO good (firing pin block and grip safeties) and not so good (increasing the poundage of the firing pin return spring). If you are going to toss a gun off a building and the only thing that is going to keep the firing pin from setting off the primer is the spring then you are going to need a stout spring.
If you increase the poundage of the FPRS (firing pin return spring) you must increase the poundage of the hammer spring if the hammer is going to have enough force to move the firing pin. In an auto pistol if you increase the weight of the hammer spring you must reduce the weight of the recoil spring so the slide will have enough force to cock the hammer. Its that relationship thing again.
A few years ago I worked on a handgun that had a double action trigger pull in excess of 20#. This was due to the before mention FPRS. To get the gun down to a 6# double action trigger pull I had to start at the FPRS then replace the hammer spring and go to a higher poundage recoil spring. The key was the work within the new relationship of each spring. Next the trigger return spring.
Trigger Return Spring… This necessary spring does add to the combined weight of the trigger pull. In some guns the spring can be lighten to reduce the combined weight. What you should consider before you do this is how fast of a trigger reset do you need. Most of use will not be able to use all of the speed a strong trigger return spring deliverers. In a gun like the Ruger SP 101 where this spring does dual duty there is little you can do in this regard with out changing the hammer strike. R S
The mag spring. There is a trend going on where a lot of shooters are replacing there mag springs with extra power spring. Where this may be a good idea is if the recoil spring is cycling the slide so fast that the factory spring can not drive the next round into position before the slide passes over the round. I have never seen this, but I wont say it does not exist. What an extra power mag spring will do is make your mag harder to load. It can also slightly slow down the slide.
The lowly mag spring gets blame for a lot of feeding problems when the cause is with the ammo or the round not freely sliding under the extractor into the breach face. This is not all that uncommon on the Witness. Another problem that the mag spring can get credit for is when the recoil spring is coil binding and not allowing the slide to fully retract. A recoil spring buffer can all cause this as happens with Kimbers
Where the mag spring can often cause feeding problems is when it allows the round being feed to nose dive.
I have never used an extra power mag spring. I also don’t change out my springs. I know we have been told to change these spring and also not to leave Mags loaded as it will weaken the mag spring. This may be good advice, it certainly makes sense, but I chose not to take this advice until I see a good reason. R S
Last but not least, the recoil spring. This spring acts as a shock absorber for the slide and frame. It supplies the force to strip a round from the mag and seat the round in the chamber. The spring also plays an important part in stopping the action from opening prematurely upon firing the handgun.
To often shooters do not pay enough attention to tuning the recoil spring. This is not helped by manufactures like Tanfoglio who under spring their handguns. By going to a light weight recoil spring in the Witness fewer guns will be returned for failure to feed, because children can shoot the gun and it will cycle. They can also rack the slide to load. The spring that is right for you 12 year old is most likely not right for you.
This one size fits all approach is not without problems. The week recoil spring allows for the slide to slam into the frame upon firing.
This greatly affects felt recoil. The weaker spring can allow the slide to start to unlock early which can affect accuracy and wear and tear on locking lugs.
I tune my guns depending on the use and ammo I will be using. If the gun is going to be carried for protection, then I will use the heaviest spring weight that will function when shot weak hand only.
Guns for range and match will have slightly stronger weight springs.
Remember that Relationship thing. If you make changes to a hammer spring or firing pin spring you may also want to look at the recoil spring. Small changes my be O.K., Larger changes my hurt you relationship. I hope you find this helpful. R S