Quick Load question regarding powder burn rate

[cowtownup]

For those of you who use QuickLoad... How much are you having to adjust the burn rate of the powder to reach the range measured velocity data?

I was using IMR-4064 and had everything adjusted really close. As I would increase charge weight, the velocity would follow nicely. I switched over to VARGET and determined the powder charge needed to achieve the barrel time of my 4064 load. Everything looked good on the screen and I went to the range expecting velocities around 2780 FPS. Well, first round I sent was 2867 FPS, almost a full hundred over what I expected. After coming back to the software from that range trip, I had to adjust the burn rate around 16% to get said velocity and as you can imagine I was OVER PRESSURE.

What kind of burn rate adjustments do you typically see? 3-5% or much greater???

Thanks..

[LongRange]

I don't shoot those powders but for RL-17 RL-22 normaMRP and IMR7828ssc I had to adjust just about the same amount you did...with RL-25 QL was 30FPS slower RL-19 was within a couple of FPS as was IMR4831 and H4831...If I remember right H4350 was 50FPS faster than QL...I think it depends on powders and lots...I know when I start running compressed loads its up around 20+%...if your loading close to the lands you might want to play with your start pressures.

[earl39]

Darkker should chime in but i have said more than once that Varget is bad about different lots having a large variance in performance. RL-15 seems to hold a tighter tolerance for stick powder and your 4064 does really well. I use BLC-2 and have used a lot of different lot numbers over the last 40 or so years and have yet to have a large shift in load performance lot to lot. The 10% Hodgdon calls for is only if you are running midrange loads not running the ragged edge so your 16 percent to me would not be out of line.

[eddiesindian]

Yep,expect that or more. I've used Varget for over 10 years and what I've found is when it works? It does the job fantastically. But lot to lot?...not so good.

[darkker]

Cowtownup,

The very best there is, and there seem to be VERY FEW who are this tight, is 5-7% total BR variation. MOST have a nominal variance of 5-8%, so that 8% could be up or down, allowing for a total swing of 16%.
I have lived through much more than a 10% swing from Varget.

A word of caution for you, about to much faith in QL. Anything coming out of Eurenco, they are all too happy to tell Hartmut anything he wants. Beyond them, no one tells him Shyte, and the Pressure Trace confirms he REALLY struggles to accurately describe General Dynamics powders; especially the ball powders. So the only way for QL to know about them is Bomb Testing. Unfortunately this is not only very expensive, but limited in description of a powders abilities. Really isn't much more useful than a burn rate chart. So while it is very intriguing, and fun to play with, don't think that it will actually tell you the pressures you are running, or how the burn curve looks.

[cowtownup]

Well, I certainly appreciate the word of caution. I really wasn't expecting such a large swing in burn rate from lot to lot... Here in eastern NC, we have decent swing in temperature throughout the day so I may setup QL for a 70 degree day and then by the time I can shoot its 85 degrees.. Or vice versa... My point being that there are so many variables that for the recreational shooter that I am its really hard to control everything. I'm still going to toy with it as time permits, but I learned a good lesson here...

[smlzerolimit]

I would make sure you have every setting right in quickload, I love the program, but many people do not change some of the factors in it, like barrel length, etc.. You need to be precise as possible , the further you seat the bullet out the more powder you can use. If I put in everything correctly, I am usually within 20 fps either way. I don't even use a chronograph , I take what it gives me and usually have to adjust it by a few fps.