01-22-2017, 04:00 AM
I'm seeing a lot of problems right off the bat here.
1. 2 different brass head stamps are being used, presumably with the same charge weights.
2. Relying on a Lyman digital scale for throwing charges without checking charge weights on another.
3. Loading for a belted magnum that has additional parameters to consider that are not present with other cartridges.
4. Lack of specific data that is normally shared by reloaders, like case trim length.
5. This is a big one too: No mention of working up a load that I have seen in the thread. Maybe I skipped over it, but nowhere is it mentioned what your velocities were with starting loads going up to maximum.
If you are looking in a book and picking a max load, then loading it, this is a good time to step back and realize that a lot of things are missing from how we approach hand-loading and reloading. It is essential to know what the start loads are for the components you are combining for your cartridge.
For example, I load for .260 Remington as well. My Lapua brass has less case capacity than my once-fired 7mm-08 brass necked down, so I had to start load development all over. I would be violating basic load procedures by taking my pet load with the other brass and translating it to the Lapua brass.
When I see mixed brass from different makers, only max loads listed, no trim length, no mention of full-length versus neck-sizing only, particularly with .300 Win Mag, it's time to stop and get some assistance so these kinds of things don't happen.
.300 Win Mag has very strict minimums and maximums, since the case volume is so high with a long powder column, and loading for a belted magnum brings with it certain chances for case stretch that weakens the web, especially if you are full-length sizing without concern for your chamber's dimensions.
What was your headspace measurement for fired brass to the shoulder?
Did you trim to length?
1. 2 different brass head stamps are being used, presumably with the same charge weights.
2. Relying on a Lyman digital scale for throwing charges without checking charge weights on another.
3. Loading for a belted magnum that has additional parameters to consider that are not present with other cartridges.
4. Lack of specific data that is normally shared by reloaders, like case trim length.
5. This is a big one too: No mention of working up a load that I have seen in the thread. Maybe I skipped over it, but nowhere is it mentioned what your velocities were with starting loads going up to maximum.
If you are looking in a book and picking a max load, then loading it, this is a good time to step back and realize that a lot of things are missing from how we approach hand-loading and reloading. It is essential to know what the start loads are for the components you are combining for your cartridge.
For example, I load for .260 Remington as well. My Lapua brass has less case capacity than my once-fired 7mm-08 brass necked down, so I had to start load development all over. I would be violating basic load procedures by taking my pet load with the other brass and translating it to the Lapua brass.
When I see mixed brass from different makers, only max loads listed, no trim length, no mention of full-length versus neck-sizing only, particularly with .300 Win Mag, it's time to stop and get some assistance so these kinds of things don't happen.
.300 Win Mag has very strict minimums and maximums, since the case volume is so high with a long powder column, and loading for a belted magnum brings with it certain chances for case stretch that weakens the web, especially if you are full-length sizing without concern for your chamber's dimensions.
What was your headspace measurement for fired brass to the shoulder?
Did you trim to length?
NRA Basic, Pistol, Rifle, Shotgun, RSO
CCW, CQM, DM, Long Range Rifle Instructor
6.5 Grendel Reloading Handbooks & chamber brushes can be found here:
www.AR15buildbox.com
CCW, CQM, DM, Long Range Rifle Instructor
6.5 Grendel Reloading Handbooks & chamber brushes can be found here:
www.AR15buildbox.com