Quickload Question - 6-6x47L Improved

[mps5949]

I have a 6-6.5x47L imp. I am trying to get quickload to correlate to actual chrono readings. I have modified the cartridge data for actual barrel and have adjusted most of the other variables to actual data, however QL is still predicting a velocity about 200 fps higher than I have actually measured. I know I can adjust weighting factor and the Shot initiation pressure, but I dont want to do anything unrealistic, so looking for some experience...

Here is gun data:

6-6.5x47L imp
95gr Nosler #24095
1-8 twist
24' barrel
CCI 450 small rifle magnum
39 gr H4350 @75F ambient
Case Length 1.835'
COL = 2.567',bullet 0.010' jammed)
case capacity = 48.9 gr H2O

QL Settings:

Shot start initiation = 6900psi
Weighting factor = 0.45

I have measured chrono data of 10 shots = 2910 fps average

QL predicts 3102 fps,can get lower, but not close enough)

If I drop shot initiation pressure, I think I have to drop it too low for a jammed bullet. If I raise weighting factor I have to go above .5 and am closer to a cylindrical case.

Which of these two factors should I favor to get a good correlation without being unreasonable?

PS: My 6BR correlates quite well to QL predictions!

Thanks

Mike

 

[stosh]

Don't know about H4350 but 2900 seems mighty slow for a 6x47L and a 95gr bullet.

I have shot 90 gr using 40.5 of VVN - 550 at 3370 without any signs of preasure,My fav load is berger 88 with 41.0 VVN-550 for 3400.

I would think 3100-3200 would be the vel I would be looking for.

But this is my gun just letting you know what mine does. And it is not an improved it is just a 6x47L,Necked down 6.5x47L case) You may be talking about a different cart, in that case nevermind.
Stosh

 

[scout1]

MPS,
In Q.L. in your powder Tile or window, if you look diectly to the left of your powder selected you will see a picture of a hand holding a pencil. Move you cursor to this button and click it. This will allow you to change the burn rate factor of your powder. Go up for faster results and down for slower results. That button also opens another button at the lower left just over the Apply and calculate box. It is a thermometer button, click this button to change the ambiant temperature that your shooting session will take place in, weather it be 60 deg or 95 deg every little bit helps.
Q.L. states that the predictions or models that the program produces can vary as much as +/- 10 percent from actual results due to lot to lot variences in commercial powder. Some are better than others. Try these steps along with what you have already done and you will callibrate the program to your specific lot of powder.

Good luck, and we will need a report with your results.

 

[mps5949]

Scout1/Stosh -

Thanks for your replies!

Mike

 

[scout1]

This article explains it all

http://www.6mmbr.com/Quickload.html

 

[mps5949]

Thanks! QL is a great tool! However, I can see where 'garbage in = garbage out' rule applies. One does need to be very knowledgeable on the inputs and be very careful how to interpret the output. Also, be very careful when switching from one gun to another. I keep forgetting to change my barrel length....

Mike

 

[scout1]

mps, anything further to report? Did you get it figured out?