09-27-2023, 03:58 PM
QuickLoad can be your friend in this situation.
Use the as-measured case volumes for the Grendel head-stamped brass and your "go-to" load for the Grendel to calculate velocity and pressure. Even though they might not closely match (reasons will be a much longer discussion) one can use the calculated velocity and pressures as baseline.
Then do the same with the resized and firefored 7.62X39 brass. Now note the CHANGE in velocity and pressure from the baseline. I have determined that QuickLoad does an excellent job in determining increase or decrease in pressure going from one load to another. This is in spite of QL occasionally not predicting the same pressures as we see in published load data.
That change will tell you how close you are to dangerous pressure levels with the x39 brass when using your favorite load.
Then, determine the new charge weight needed to match what QL calculates for the Grendel brass. That load should also be close but slightly below the velocity you get with your favorite load in Grendel brass.
- - - and yes, start below that "matching load" and work up, as always with new combinations.
Use the as-measured case volumes for the Grendel head-stamped brass and your "go-to" load for the Grendel to calculate velocity and pressure. Even though they might not closely match (reasons will be a much longer discussion) one can use the calculated velocity and pressures as baseline.
Then do the same with the resized and firefored 7.62X39 brass. Now note the CHANGE in velocity and pressure from the baseline. I have determined that QuickLoad does an excellent job in determining increase or decrease in pressure going from one load to another. This is in spite of QL occasionally not predicting the same pressures as we see in published load data.
That change will tell you how close you are to dangerous pressure levels with the x39 brass when using your favorite load.
Then, determine the new charge weight needed to match what QL calculates for the Grendel brass. That load should also be close but slightly below the velocity you get with your favorite load in Grendel brass.
- - - and yes, start below that "matching load" and work up, as always with new combinations.
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"To those who have fought and almost died for it, freedom has a flavor the protected will never know."
-- Author Unknown
"If at first you do succeed, try not to look astonished!" -- Milton Berle