Why did you have to replace the limbs?My r29 is 4 years old. Got new limbs on last month. Don’t have chrono. But noticed a big difference in speed now. Have hawk xb pro scope on it. Had to turn dial up to 450 fps the max. And I still hit high a little high. Added 25 grain washer to arrows now perfect at the 450 setting. Ata 10 7/16. Don’t recall it being that fast 4 years ago
1)The new limbs may have a higher draw weight.My ata was at 10.5 when new. Now with new limbs and ata10 7/16. Bow seems much faster
I agree with the chronograph use, all units have a "sweet spot" that will provide identical speeds. In most cases this will be about 1/4 to 1/3rd the way up from the eyes. I use two pieces of fluorescent tape on each of the front defuser arms as a reference point to shoot through.Here are a few things that can affect speed in feet per second:
1)using a different arrow-point weight combination.
2)if the crossbow has not been shot much, whether new or with new
string and cables, these may stretch as they have not settled in.
3)a change in cam timing or tuning to advance or back cams off.
4)a change in axle to axle measurements (which is just a guide line)
due to tuning and or string and cable stretch.
5)using a different chronograph or shooting through a different area
of the chronograph or light conditions which can affect a chronograph
Wishing you all the best.