I used to have one for my 9 mm. Sorry for the Sprinco guys but I definitely did not like it because :
- the rod obviously was designed for the .40 with the somewhat longer slide (compared to the 9 mm's slide), leaving the front of the rod protruding out of the slide (not a great sight)
- as for the "recoil reducing properties", I could not ascertain or feel any improvement over the original guide rod (I admit this is a subjective assessment)
- after a couple of shots fired, the guide rod looked like being ran over by a truck. As a matter of fact the steel rod slammed against the inner edges of the rod passage hole in front of the slide every time the slide went back into battery (not to mention the damage this could could have done to the slide)
In short, I kicked the damned thing out of my gun and went back to the OEM guide rod. Nevertheless I feel a bit sorry because the idea is not bad, the rod was a nice piece of craftmanship, well machined and finished but the concept clearly was not worked out properly for the P99. I would provide a plastic buffer (like the one found on the H&K) and solve the problem of the disalignment of the rod by adding a guide sleeve of bushing.
As things were for me, it was a waste of money.