I have been exploring the idea of only sizing the necks of my 6.5 Creedmoor brass. I have two 6.5 creedmoor rifles, one in an AR-10 platform and one is a Bolt gun.
To be clear:
NOTE - this test was run only on the bolt gun.
The results of my tests were interesting with some interesting results i was not expecting.
Just wondering if anyone has an idea why my MV would be so consistently different between the two loads.
Could it be that for the full-sized loads, there is some expansion of the case in the chamber upon firing that may have absorbed some of the pressure causing the lower MV? I would have thought that since the inside of the neck-size only case is slightly larger than the fully-sized cases, they would see a bit lower pressure but that wasnt the case at all.
To be clear:
- i will always full-length resize the cases for my AR-10 platform, no questions there.
- I am only considering neck-only sizing for my bolt action.
NOTE - this test was run only on the bolt gun.
The results of my tests were interesting with some interesting results i was not expecting.
- Cases that were full-length resize - MV averaged 2850 fps and SD averaged appx 7.5
- Cases that were neck-sized only - MV averaged 2870 fps and SD averaged appx 10
Just wondering if anyone has an idea why my MV would be so consistently different between the two loads.
Could it be that for the full-sized loads, there is some expansion of the case in the chamber upon firing that may have absorbed some of the pressure causing the lower MV? I would have thought that since the inside of the neck-size only case is slightly larger than the fully-sized cases, they would see a bit lower pressure but that wasnt the case at all.