Picked up this kit yesterday at Canadian tire for my rifle ,little tricky to install but looks nice,for a poor man.http://www.mossyoakgraphics.com/accessories/shotgun-rifle-mossy-oakr-camo-gun-kit-3296.html
Arrow Speeds Without a Chronograph (Field Test)
1. Start by shooting a group with your bow at a target from 20 yards using your 20 yard pin.
2. Mark the center of your group.
3. Next, shoot from 40 yards , still using your 20 yard pin and aiming at the same point on the target as before.