Colorado Redneck
New member
In working up loads for a 222 Remington the third trip to the range higher velocities started showing up. The Caldwell chrony was set up as near to level and aligned straight between muzzle and the target as this old geezer could make it. One of the loads is plenty accurate for prairie dogs, but it was concerning that my readings were about 200 fps fast. To my way of thinking, accuracy, consistency, and correct setting on the elevation are the most important factors. So, after making a few more rounds it was back to the range. I knew exactly the point of impact is a half inch high at 100 yards. Shot 3 rounds at 300 with the scope set at zero....which is a half inch high as stated. The group was 8.30 inches low. Pulled up the JBM Tracectory calculator, and fiddled with the velocity number till the calculator showed 8.3 inches of drop at 300. As suspected, instead of 3575 fps, it figured out at 3360 fps. Big difference! Adjusted the elevation on the scope, shot three rounds, and was pretty close at 300. Went up 2 more clicks and dead on.
I'm bumfuzzled as to the problem with the chrony. I have had this unit a couple of years, and it never gave any reason not to trust it. A couple months ago, it showed very accurately the velocity of a .204 Ruger load I have used for 3 years. So, it appears to me, a chronograph might not be the end all do all for scope settings for going down range a ways.
I'm bumfuzzled as to the problem with the chrony. I have had this unit a couple of years, and it never gave any reason not to trust it. A couple months ago, it showed very accurately the velocity of a .204 Ruger load I have used for 3 years. So, it appears to me, a chronograph might not be the end all do all for scope settings for going down range a ways.