Stupid question most likely, but I'm going to ask this anyways.
I have had to switch over to forming Winchester 243 brass into 260 since my RP brass is worn out. I had a great working load with 42gr R17 in the RP brass with 140's, so I backed down to 40gr in the newly formed 243 brass and found a load at 40.8gr using the same bullets, anything anywhere near the old load opened up drastically and the accuracy was horrible but no pressure signs were noted. I chalked it up to a difference in case capacity and left it at that until this morning.
I decided to check the H2O capacity of a few cases and here's what I found. I made sure the fired cases were all the same length as well, weighed each case on my Hornady scale and rezeroed between cases. Cases were filled off the scale with a syringe.
New WW 243 expanded to 6.5mm-54.6gr (average/5)
1x WW243 to 260-55.7gr (average/5)
1x RP 260-55.6gr (average/5)
1x and sized 243 to 260 (shoulders bumped .002")-55.5gr (average/5)
Okay, time for the stupid question. Am I going to end up needing to tweak this load for the once fired brass? I'm thinking I may end up right back next to the old load that was run in the RP brass, am I wrong?
I have had to switch over to forming Winchester 243 brass into 260 since my RP brass is worn out. I had a great working load with 42gr R17 in the RP brass with 140's, so I backed down to 40gr in the newly formed 243 brass and found a load at 40.8gr using the same bullets, anything anywhere near the old load opened up drastically and the accuracy was horrible but no pressure signs were noted. I chalked it up to a difference in case capacity and left it at that until this morning.
I decided to check the H2O capacity of a few cases and here's what I found. I made sure the fired cases were all the same length as well, weighed each case on my Hornady scale and rezeroed between cases. Cases were filled off the scale with a syringe.
New WW 243 expanded to 6.5mm-54.6gr (average/5)
1x WW243 to 260-55.7gr (average/5)
1x RP 260-55.6gr (average/5)
1x and sized 243 to 260 (shoulders bumped .002")-55.5gr (average/5)
Okay, time for the stupid question. Am I going to end up needing to tweak this load for the once fired brass? I'm thinking I may end up right back next to the old load that was run in the RP brass, am I wrong?
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