TresMon
Well-Known Member
"The Electronic (Claude Audette) Ladder Test for Load Development. "
So in my "Hand Loading for Long Range series that I wrote years ago I explained the usefulness of Claude Audette's ladder test. I received loads of PM's and e-mails with further questions after writing that multi-part article. I thought I'd throw in a little technology update on the process.
Another way to skin the same cat....
The ladder test is an economical & manual way to "see" pressure walls in the relationship between powder charge, the bore and ejecta. For a small recap, one would think just a little more powder would yield a little more velocity. and it does until you hit one of the numerous pressure wall phenomenons..
In practical application there will be a couple or thee powder charges within book min & book max powder charges that actually do not yield an increase in FPS, despite going up another increment in powder. Then the next later or second later following incremental powder charge increase will finally again yield a FPS increase. Picking a powder charge for your long range/precision load that is right at a pressure wall will yield you the most forgiving and stable powder charge and the Audette ladder test has shown us these pressure walls, manually for many decades now.
The reason that choosing a pressure wall charge is more forgiving is near obvious....it's forgiving. Wether one must go from one lot number of their favorite powder to another lot number...or perhaps a guy doesn't have the patience or desire to hand weight each powder charge with VERY precise equipment and attention to detail, or one uses a progressive reloading press which is less than the bench mark standard for accurate powder metering, etc etc.....choosing a powder charge at a pressure wall is where you will find the most consistency even when these inaccuracies of the charge weight itself is introduced, powder variances from manufacturers lot to lot can't be helped, ever changing temperature of the powder itself day to day, shot to shot- all the skews we can't hep in the world of shooting. Pressure walls could be called "zones of (charge weight) forgiveness."
Enter LabRadar. (And I have zero association with LabRadar..) We laymen have finally been provided an "affordable" chronograph that is accurate enough to specifically show us where the pressure walls are, right at the firing position with no numerous treks down range back and forth back and forth to label hits. It even negates the need for the generally agreed upon bare minimum 500 yard range for the manual Audette ladder test to be able to give clear data.
To do an "electronic ladder test" simply load 10ish rounds each at a different powder charge and fire them and obtain the MV report form the radar. Out of the 10 or so rounds you fire, most will have a "more powder yielded = more fps" scenario. Burt for those rounds that more powder produced the same or nearly the same exact FPS...poof...these are your pressure walls standing up and being accounted for.
Choose the pressure wall that's closest to your p[referred muzzle velocity then .go play with primers, neck tension & bullet seating depth to find the best load. And you just saved yourself a substantial amount of barrel life in the load development process.
God bless and stay at it boys.
TresMon
So in my "Hand Loading for Long Range series that I wrote years ago I explained the usefulness of Claude Audette's ladder test. I received loads of PM's and e-mails with further questions after writing that multi-part article. I thought I'd throw in a little technology update on the process.
Another way to skin the same cat....
The ladder test is an economical & manual way to "see" pressure walls in the relationship between powder charge, the bore and ejecta. For a small recap, one would think just a little more powder would yield a little more velocity. and it does until you hit one of the numerous pressure wall phenomenons..
In practical application there will be a couple or thee powder charges within book min & book max powder charges that actually do not yield an increase in FPS, despite going up another increment in powder. Then the next later or second later following incremental powder charge increase will finally again yield a FPS increase. Picking a powder charge for your long range/precision load that is right at a pressure wall will yield you the most forgiving and stable powder charge and the Audette ladder test has shown us these pressure walls, manually for many decades now.
The reason that choosing a pressure wall charge is more forgiving is near obvious....it's forgiving. Wether one must go from one lot number of their favorite powder to another lot number...or perhaps a guy doesn't have the patience or desire to hand weight each powder charge with VERY precise equipment and attention to detail, or one uses a progressive reloading press which is less than the bench mark standard for accurate powder metering, etc etc.....choosing a powder charge at a pressure wall is where you will find the most consistency even when these inaccuracies of the charge weight itself is introduced, powder variances from manufacturers lot to lot can't be helped, ever changing temperature of the powder itself day to day, shot to shot- all the skews we can't hep in the world of shooting. Pressure walls could be called "zones of (charge weight) forgiveness."
Enter LabRadar. (And I have zero association with LabRadar..) We laymen have finally been provided an "affordable" chronograph that is accurate enough to specifically show us where the pressure walls are, right at the firing position with no numerous treks down range back and forth back and forth to label hits. It even negates the need for the generally agreed upon bare minimum 500 yard range for the manual Audette ladder test to be able to give clear data.
To do an "electronic ladder test" simply load 10ish rounds each at a different powder charge and fire them and obtain the MV report form the radar. Out of the 10 or so rounds you fire, most will have a "more powder yielded = more fps" scenario. Burt for those rounds that more powder produced the same or nearly the same exact FPS...poof...these are your pressure walls standing up and being accounted for.
Choose the pressure wall that's closest to your p[referred muzzle velocity then .go play with primers, neck tension & bullet seating depth to find the best load. And you just saved yourself a substantial amount of barrel life in the load development process.
God bless and stay at it boys.
TresMon
