velocity question

[goblbustr]

Ok fellas for years I never owned a chrono. Well I bought one now I am confused as hell. I always fired at 500 yds with a 100 yd zero and adjusted up until I was hitting on target. I then would use my software entering current data and changing velocities until my clicks at 500yds matched my actual clicks. In this instance the velocity was 3350. I have taken a lot of game with this rifle and shot critters as small as groundhogs at 700 plus based on that velocity. Today I take my new toy to the range expecting it to tell me my velocity was in the 3350 range. Well imagine my surprise when I found out I was averaging only 3100. What am I doing wrong? based on experience with this rifle if I use the 3100 velocity for a click chart it will be off.

 

[Joe King]

I would go with my drops and forget the velocity.
Unless you bought a high end chrony there's no guarantee that it's reading right, and if you go out another day with different ambient light I bet you get different velocity figures. What you can do is (if you have acces to several other chrony's) set yours and 2-3 others up in series and shoot through all of em at the same time. That would give a definite answer as to how accurate yours is. In my opinion if it's a budget chrony and reads consistently it can still be indispensable as a load development tool since it will help you nail down loads that yield low E.S.

 

[JeffP40]

The only thing that really matters is the bullet and the come-ups match. What you are thinking is the bullet is now not going where you want it now that the velocity is not what you thought it was. Almost everyone develops a load, uses a chart, and then tweaks the bc, vel., or both to get the numbers to match the impact. Chronos are good for getting a good idea of what is happening with a load. I tend to use them to see when I am topping out with a powder weight. You will find the velocity will increase in lower increments as you reach top pressure.
To get yout original data, you used a speed that matched your bullet impact. No difference here, you just know the numbers don't match.