CZ P07 Recoil Spring Upgrade?

**Teamcam** · 08-11-2019, 14:28

Good Day members

A friend has a new P07 which he maybe shot less than 150 rounds through.
Some dude told him to upgrade his spring kit to a heavier spring.

Is this advisable?
If yes, which kit should he get?
I don't see the need, but if its a good move then i will let him in on it

**Grant9** · 08-11-2019, 14:32

Why?

**BEX** · 08-11-2019, 14:46

I cannot imagine why it would be necessary. Maybe to reduce felt recoil on hot loads?
My P07 is about 2-3 month and I have about 1500 rounds through it without a single problem from +P+ to very mild hand loads.

**pblaauw** · 08-11-2019, 14:51

DMP recoil reduction kit from Jizni. I have it, and makes quite a difference. My daughter shoots my P07 and being 12 she doesn't have the strongest grip yet. That said, that P07 also has a ton of other Cajun stuff. Is it a 'must have'...no, but it does help.

**GAZZAMCK** · 08-11-2019, 15:07

Originally Posted by pblaauw

DMP recoil reduction kit from Jizni. I have it, and makes quite a difference. My daughter shoots my P07 and being 12 she doesn't have the strongest grip yet. That said, that P07 also has a ton of other Cajun stuff. Is it a 'must have'...no, but it does help.

I have to wonder if one had a bad round, maybe a lesser load, would the heavy recoil spring cause a malfunction should it not cycle the slide fully

**GAZZAMCK** · 08-11-2019, 15:08

I am on my second CZ recoil spring

First one was blue, gun ate through the front of the plastic housing at the muzzle end

Second one is black, so far so good

**Marius@Jizni** · 08-11-2019, 15:46

Originally Posted by Teamcam

Good Day members

A friend has a new P07 which he maybe shot less than 150 rounds through.
Some dude told him to upgrade his spring kit to a heavier spring.

Is this advisable?
If yes, which kit should he get?
I don't see the need, but if its a good move then i will let him in on it

I can't see why somebody would recommend a heavier spring. If you predominantly shoot lighter loads, you can get away with a lighter spring which will transfer less felt recoil. More so if you still have the older, blue, spring that GazzaMck mentioned.

Remember that your springs start hard and get softer with use, until they reach a level where you replace them. By changing to a softer spring early, and replacing it more frequently, you can stay in the softer (less recoil) end of the useable spring range. To warrant changing a new spring to a harder one, one would want to cure some problem that I'm not aware of.

**Pirate** · 08-11-2019, 16:47

How would a softer spring result in less recoil? Or is this used in conjunction with reduced load ammo?

**Marius@Jizni** · 08-11-2019, 18:18

Originally Posted by Pirate

How would a softer spring result in less recoil? Or is this used in conjunction with reduced load ammo?

It should not result in less recoil, no, but it seems to result in less felt recoil. Ultimately the total recoil impulse, transferred to the shooter, should be the same. Spring changes only allow you to determine how the force is spread out over the cycle.

A softer recoil spring moves the force a bit later in the cycle, but go too soft and the slide hits the frame causing a peak. A buffer can spread the final bump out a little bit, lowering the peak. As the slide returns into battery, the weight of the recoil spring also affects the timing of the slide going into battery relative to the timing of the front sight returning to the target. This seems to affect how well the sights return to target.

Springs differ not only in terms of the spring constant, but also in terms of the length. So a softer spring is often a bit longer to maintain enough force at its most extended position to ensure reliable return to battery. This, however, makes the force ramp up slower relative to a harder, shorter spring, which does not seem to be exactly what we want. The DPM system, that pblaauw referred to, is nothing more than a dual spring system that allows the force to start relatively low and ramp up quicker later in the cycle. (A third spring does the same job as the buffer right at the end of the cycle.)

Whatever the physics, the difference is noticeable. I have a fully adjustable DPM system in my Shadow, that allows me to not only play with the main spring to determine the 'base load', but also with the position that the second spring comes into play. Playing around with it, I could notice the recoil feeling less as I moved 'softer and later' until I could notice the sights not settling as I used to. Staying at the softest base load and adjusting the second spring to come into play slightly earlier settled the sights beautifully. I expect it to have different results in other shooters' hands, with some even prefering a single spring setup to a dual setup.

Similarly, I experience 147gr bullets as 'soft recoiling' while others describe the recoil impulse of a 147 gr bullet as 'sluggish.' The ammo and the shooter do seem to play a role. I therefor see the changing of a recoil spring more as 'optimising the system' than 'upgrading the gun.'