Quick load question
- Thread starter coyoteking
- Start date
In order to get more accurate chamber pressure guesstimates you need the case capacity of a fired case. Then you need chronograph readings and then adjust the powder burn rate in Quickload until it matches your chronograph velocity.
Quickload defaults to the smallest case capacity and as an example with the .223 it can make a 5,000 psi difference in chamber pressure vs actual. SO you need the case capacity and crongraph velocity to get close to the chamber pressure estimate.
Quickload defaults to the smallest case capacity and as an example with the .223 it can make a 5,000 psi difference in chamber pressure vs actual. SO you need the case capacity and crongraph velocity to get close to the chamber pressure estimate.
That’s quite a difference. I’ll measure the volume on a couple of cases.
Thank you! I’ll get some more measurements for a more accurate result.
coleman1495
CGN Ultra frequent flyer
- Location
- Whitecourt
60.8kpsi @2.350”coal and 43.5gn H2O case capacity
I did some QL modelling for your 22-250.
OBT for 26" bbl is 0.9661 mS for this example.
Your load, generic to the program defaults for weights ,measures etc., 36.4 gns Varget 3818 ft/s ( require to adjust Ba a slight bit as you clocked 3830 ft/s, I didn't do that in the model, but would if it were my load) for 66 038 psi, barrel time node 0.928 mS.
Alternatively, 34.86 gns , 3679 ft/s, 58 838 psi, OBT 0.9661 mS
With H-4350, 38.54 gns, 3672 ft/s, 59 538 psi, OBT 0.9661 mS
The H-4350 load models real well, almost an OCW load, is an OBT, 104% load density.
You may wonder why the H-4350 load and the Varget load have the same barrel time, different pressures, very close to the same velocity, IT is that the acceleration rates are different.
Anyway, these are models and should be taken as such.
A very minor tweak in the Ba to get velocities to line up are an indication that the model is accurate with the information provided.
Hope this helps.
OBT for 26" bbl is 0.9661 mS for this example.
Your load, generic to the program defaults for weights ,measures etc., 36.4 gns Varget 3818 ft/s ( require to adjust Ba a slight bit as you clocked 3830 ft/s, I didn't do that in the model, but would if it were my load) for 66 038 psi, barrel time node 0.928 mS.
Alternatively, 34.86 gns , 3679 ft/s, 58 838 psi, OBT 0.9661 mS
With H-4350, 38.54 gns, 3672 ft/s, 59 538 psi, OBT 0.9661 mS
The H-4350 load models real well, almost an OCW load, is an OBT, 104% load density.
You may wonder why the H-4350 load and the Varget load have the same barrel time, different pressures, very close to the same velocity, IT is that the acceleration rates are different.
Anyway, these are models and should be taken as such.
A very minor tweak in the Ba to get velocities to line up are an indication that the model is accurate with the information provided.
Hope this helps.
