I got a Sprinco recoil management system for my P99 9mm because I found the felt recoil to be somewhat sharp when I first got it. The Sprinco system was easy to install, has never caused any problems and reduces felt recoil, to my hand anyway, by about 25%. If felt recoil is what you're dealing with by the way, I found a Hogue Handall grip to help some too.
It seems hard to believe that an outsider could manufacture a spring that's better (feels better, more reliable action) than what Walther put together with all their research.
When you read this forum there are so few reports of gun malfunctions that I really wouldn't want to change any of the mechanicals. The only component that had some issues were the magazines and those appear to be fixed with the latest revisions.
If you're messing with a range or plinking gun, go ahead and experiment. If it has a more serious purpose, leave it alone. Like Clint Smith wrote about all the folks that come to Thunder Ranch with modified Glocks. More trouble than they are worth. "Take it out of the box and shoot it".
As has been stated here already ????.. when you change the recoil attributes of your pistol, you run the risk of having a failure. This happens most frequently when you ?limp wrist? the pistol while shooting. Normally the recoil force is figured to account for a less than perfect hold on the weapon. As you reduce this force or change its direction, it becomes more important that you have a firm grip on the gun. So using the recoil management system can work well as long as you do your part all of the time. Walther knows that in a self-defense situation, that does not happen all the time so they made sure that there was enough reserved power in the recoil to cock the gun, no matter what. I have held my .40 so loose that it almost jump from my hand, and it still ejected and cocked like always. I like it when a gun tries to make up for a shooters mistakes and ?keeps on ticking? .
The plastic guide rod ????.is just that - a guide. NO forces are placed on the rod at all. It merely acts as a guide so the spring compresses straight back, without any kinking.
You could use one made from cardboard, and it would work fine - for awhile. Here is something else, I?ll bet few think about. The guide rod with its convoluted surface and flat spring design ? acts as a ?cooling fan? for the barrel. Yep, the action of the ?flat? spring when it compresses = ?pumps? air around the barrel. The guide rod is designed to allow this air to move up and back along the length of the barrel. When you change this design, you remove this purposely placed cooling system. Now what I have described is the system used by SIG ARMS ????and if I am not mistaken ? Walther uses the same design. Its been awhile since I have fired my .40 cal and looked at the guide rod system. Check it out and see if they don?t use a flat recoil spring and a rod with fins running its length??? These engineers are pretty smart ??..and when you start messing with their design, you had better be smarter then they are or you may do harm to your weapon [ without even knowing it ].
I have been using the Sprinco for awhile and, even in some awkward handling of the pistol, it's never failed to re-cock. I'm no engineer, but it's hard to believe the cooling function of the OEM flat spring is that significant. Also, you can't help but notice that the Sprinco guide rod and spring are well-made and given that and the materials, cost a lot than the OEM. Engineers are bound by cost constraints, no? I was told when I bought the P99 and asked for a comparison between it and the HK USP that a significant difference was that the HK, because it had a metal guide rod and recoil reduction system, cost more and had lesser felt recoil with the same reliability, but that buying a Sprinco system would put the pistols on an equal footing, at least in that respect.
Sniper is entirely right about the forces on the guide rod when it's installed on the frame; almost no forces on it. Mine bent noticably when it was installed in the slide though as it's only held by the edge. There is a significant bending force in this condition, and as the plastic rod is a two piece element, it wasn't holding up well. Perhaps I just had a loosely fitted joint in my guide rod. Not a big deal as it is a wear item, but it seemed flimsy to me. The steel one stays where it should.
His comments about altering the recoil force make sense too.
As to the "air pumping" qualities of a flat spring and fluted rod, I doubt that was a consideration. Please correct me if there is some contradicting info from SIG engineers. I can't imagine any measurable differences in airflow around the barrel due to the aerodynamics of the spring/guiderod. It must be mighty turbulent around the barrel due to the speed of the slide moving over it.
As to the "air pumping" qualities of a flat spring and fluted rod, I doubt that was a consideration. Please correct me if there is some contradicting info from SIG engineers.
Apparently, several pistol manufacturers use the same air cooling technique, as I was able to quickly find the below paragraph describing the inovative GLOCK design. Please note the last sentence. I am not trying to prove anyones "claims" - only to pass on the information that I have read from credible sources
information courtesy of GLOCK
Like many designs, tiny changes can have huge effects to over-all function.
Without knowing the exact causal relationships in these designs, we run a serious risk when we tamper with them.
The hammer-forged rifling in Glock's barrels is equally innovative. Called "Hexagonal," this rifling lies somewhere between conventional land and groove and H&K's "Polygonal" bores. With a right-hand twist of one turn in 9.84 inches, this hexagonal profile (in cross-section a series of six small arcs connected by flat surfaces) provides a better gas seal, more consistent velocities, superior accuracy and ease of maintenance. A single-coil recoil spring under the barrel rides on a polymer guide rod which is hollow to serve as a cooling air pump.