The basic idea is to determine the fastest powder that can be used within the limits of reasonable pressures and have no less than an 85 to 90 % of the case filled with powder.

Step 1 -           Setup QL for your rifle and cartridge.  See QL instructions.

Step 2 -            Starting with a known or common bullet and powder enter a charge weight that will produce an OBT.  See table below.  

Step 3 -            List the loads that equal that barrel time.  Open the Propellant Setup Window and select the radio button, “the Barrel Time of Entry Load”.  

Step 4 -            Sort the list to select loads that have;

a.      Safe pressure limits

b.     85 % or better, percentage fill

c.      98 % Powder burnt or better

d.     Acceptable MV’s

e.      Available powder

Loads that meet these criteria will come closes to achieving an OBT load for your rifle.  Once actual MV’s are determined QL can be adjusted via the burn rate and weighting factor to further fine tune an OBT load.