Has anyone ever heard of these recoil reducing spring sets for pistols, this guy claims to have approached HK and Glock about the idea, been rejected, then had his idea effectively stolen, either way he makes the springs for many models that they don't. I'm curious to know how long they will last before wearing out, anyone have any experience? Heres the website URL http://www.dpmsystems.com/en/

This is just another hustle. You can't change recoil with a spring or buffer.

You can change the time but the amount.

Don't HK USPs (fullsize) already have some sort of recoil-reducing setup?

Yes, this guy claims to have invented the recoil reducing spring designs used in the USP line and the baby glock pistols, they look identical as far as I can tell, which leads me to believe it is the real deal. They sure work in my MK23 (the HK originals that is).

ETA: I am paraphrasing with regards to HK and Glock stealing his design, he claims to have approached them,  been rejected, then HK and Glock both introduced similar spring setups a short time later. This is 3rd hand info, so I am by no means speaking on his behalf.