I am new and I just bought a Five-seveN and PS90. I have both guns, but I have not received the side rails yet to test if they will go on, but I have leupold quick release scope rings and also another brand that I don't remember. I had planned on using those to mount my light assuming everything fit. I actually bought some rings by mistake that were to short to mount my scope to my Tikka T3 Tactical, so I think those will come in handy attaching the light. I'll let you know if it worked when i receive my side rails.