Joel Russo
Well-Known Member
The shiny round mark you are seeing is the result of brass flow to the case head. This is indicative of max load or near max load. You really don't have any idea of what your max load is unless you properly conduct load development. Sticky bolt lift is an indicator of approaching max load or at max load, but you need to know what's going on in the chamber by taking precise measurements! I suggest you mic a virgin piece of brass at the web, and write that measurement down. Now start over with your load development and only shoot one shot out of a piece of brass. Do this as you increase powder to attain your target velocity. Measure your case expansion over that of a virgin piece. You should not exceed .002" max growth, and still retain your target velocity. If not, then you need to change powders. You will see growth as you increase your powder charge. Of course, you will be monitoring velocity and ES over the chronograph, and be deciphering that info as well. After you have something that looks respectable, then start playing with seating depth. Don't just look at your group, read what it's telling you. Assuming your skills are in order, then the print on the target is indicative of what going on with your load. You may have to adjust your powder charge to bring you back to your target velocity. This is the only way to know what's going on in your chamber. You're just guessing with any other approach.
