Home Forums Reloading Big Game Rifles Question for quickload users

I just started playing around with the program and I am seeing something interesting. I adjusted the burn rate (Ba) of my H4350 to match the velocities I have been getting with 130 accubonds. When I use that same adjusted burn rate for 130 bergers, it does not match the velocities I am getting with that bullet. Is it normal to adjust the Ba for different bullets even using the same lot of powder? Thanks.

I wouldn't mess with the burn rate.

If you want to improve your results, start measuring the water capacity of your cases and adjust that instead.

What antelope sniper says, plus I use the oal measurement that assumes the bullet is seated to the lands.

I try to get very accurate measurements on the bullet, also. They can vary from default database by quite a bit and I try to at least get the length and weight right. Bearing surface length and diameter is also something that can affect the prediction.

Bullet composition is a factor, some bullets are harder than others.

I have found Quickload to be surprisingly accurate if given the right information with bottleneck cartridges, but the .45-70 is a hard one to predict. I always seem to have to shoot a baseline with it, and then adjust parameters from there, usually case capacity. I have to use a "fudge factor" of 103.2% to 107% of default case capacity for that cartridge or it will way overestimate the pressure/velocity. The amount of fudge is dependent on bullet weight, adding about 3.2% for heavier bullets (420 to 540 grains) to 7% for lighter bullets in the 300 grain weight class.

Primer brisance cannot be adjusted, either.

I've been putting in water capacity, c.o.l and case length. Then adjusting the burn rate to match the velocity of test rounds. I'll start playing around with bullet measurements as well.

Before you changed the powder property, how do the velocity differentials compare (chrono vs QL) between your two projectiles with the same input parameters kept constant (except for bullet/seating inputs)? Do both bullets have higher chrono velocities compared to QL? or lower? Are they similar in magnitude?

Weight factor and initiation pressure can also be used to fine tune the model.

All 3 bullets that I shoot with this powder are faster over the prochrono than the quickload prediction. I played with it some more and realized that my velocites are 15' from the muzzle. I used my ballistic program to estimate the muzzle velocity, and after adjusting the burn rate to match one of the bullets, that same burn rate predicts very close to what I'm getting for velocity with the other two bullets. This is a very cool program:) I'm using it to try and find loads that match the optimum barrel timing nodes from Chris Longs calculations.
A friend of mine has a very accurate load for his 300WM, in may he shot a 5 shot 4" group at 1050 yds. He just got the quickload program so he entered the specifics from that load and after adjusting the burn rate to match his actual velocities, the barrel timing falls exactly on an optimal node. Could have saved himself some time and component's finding that load if he had the program before;)