After using the reloading data provided by AA and other sources to get a handle on the basics of safe reloading I realized that to get a better understanding of why the rounds perform great or poorly with different powder loads vs the harmonics of my 16" AA bbl, I need to understand a little more about the 'Jump" to the lands. After recommendations from several members I now have the Hornady AOL Gauge with their 'Grendel' case as well as a Comparator to determine the cartrige length to the oglive.
For my Gren this is what I have measured for the different bullets I have shot:
---------Chamber-------/------Loaded
Bullet-- COAL--Comp----/COAL--Comp----JUMP
120PH-----2.224- 1.744-/ 2.224- 1.744--- .000
120NBT---2.243- 1.715-/ 2.250- 1.715--- .000
120TTSX--2.283- 1.748-/ 2.260- 1.721--- .027
123AMAX-2.265- 1.693-/ 2.260- 1.682--- .011
123SMK---2.295- 1.797-/ 2.260- 1.762--- .035
125 NP----2.250- 1.725-/ 2.200- 1.675--- .050
130SCIR--2.295- 1.674-/ 2.260- 1.639--- .035
You can see that the Jump varies form .000 to .050. Am I looking for the best Jump for each bullet or a general jump for my particular barrel? Or is it a matter of balancing the powder weight and Jump for each bullet? I haved some great sub MOA groups from the SPH and SMK's and should be doing better with the AMAX and NBT's.
For my Gren this is what I have measured for the different bullets I have shot:
---------Chamber-------/------Loaded
Bullet-- COAL--Comp----/COAL--Comp----JUMP
120PH-----2.224- 1.744-/ 2.224- 1.744--- .000
120NBT---2.243- 1.715-/ 2.250- 1.715--- .000
120TTSX--2.283- 1.748-/ 2.260- 1.721--- .027
123AMAX-2.265- 1.693-/ 2.260- 1.682--- .011
123SMK---2.295- 1.797-/ 2.260- 1.762--- .035
125 NP----2.250- 1.725-/ 2.200- 1.675--- .050
130SCIR--2.295- 1.674-/ 2.260- 1.639--- .035
You can see that the Jump varies form .000 to .050. Am I looking for the best Jump for each bullet or a general jump for my particular barrel? Or is it a matter of balancing the powder weight and Jump for each bullet? I haved some great sub MOA groups from the SPH and SMK's and should be doing better with the AMAX and NBT's.
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