Tenpoint string for Nitro XRT and Vapor RS470 are the same. This string is pre-stretched. Are the Limbs on the Nitro XRT and the Vapor RS470 the same? I have both bows. When chrono'd with the same 460gr EVO-X bolt the XRT only shoots 405fps and the Vapor shoots 448fps. The Nitro XRT was registered with Tenpoint when purchased last year. It is only one year old with not a lot of shots. When new, the 405fps was the same as now. I assumed the speed loss was from not using a 370gr bolt. Both the Nitro XRT and the Vapor RS470 are rated to 470fps if using a 370gr bolt. Can you please explain why there is such a large speed loss for my Nitro XRT when compared to the Vapor RS470? I want to point out that in all other respects, the Nitro XRT seems to shoot very well and very accurate. But the speed difference is statistically significant compared to the Vapor RS470.