Thread: Frustrating arvo at the range. Powder charges.

Originally Posted by gqhoon

Respectfully, you haven’t followed Cortina’s method, so you shouldnt be surprised that you’re getting different results.

Starting again, load from 22.0 to 24.0gr in 0.2gr increments. Only 1 round at each weight. Seat projectiles to mag length or 20 thou off jam. Shoot over a chrony and record velocity.

Use ChronoPlotter to plot the velocities against powder weight and look for flat spots as per the graph below.
Attachment 195381

Selecting the middle of the flat spot, run a seating depth test starting at the depth used in the powder charge test above, and seat progressively shorter CBTO at 3 thou increments. Shoot 3-shot groups and record velocities. Look for where both small groups and low SD coincide. That’s your load.

Ahhhh thank you for putting it in simpler English