I’m sure this has been discussed before but I wanted to ask anyways. Started load development with a new barrel using virgin brass. 6mm creedmoor, 4831sc, Berger 108eh, and cci br2 primers. I run all the new brass through sizing due and expanding mandrel. Then chamfer and debur. My question is if I find a load with this virgin brass once I start running once fired will my load be way off? Or just need to fine tune it back to the same velocity? Also anyone running over 45 grains of 4831sc? I’ve gone up to 45.2 and no pressure signs at all.
Virgin brass
- Thread starter Aggie14
- Start date
Can't comment on 6mm creedmoor specifics just preparing new cases.
Here's my process,
1. Inspect for defects that cannot be remedied and remove those cases.
2. I debur the flash hole and uniform the pockets. I'm not sure the latter is necessary, but I do it out of routine and since I paid good money for the tool.
I guess I can justify this step since uniforming makes it easy to clean primer pockets in the future.
3. I check the length and rarely, if ever do I have to trim but I check just to make sure.
4. I chamfer the necks inside and out.
5. Tumble to smooth the surfaces of the cases and remove surface films. It seems the mfg.'s process leaves a film on some brand of the cases.
6. I full size to remove neck dents, align the neck with the body of the case, and to produce a uniform inside neck diameter. I do not push the shoulder back* or extrude the case.
*I did encounter a lot of Hornady cases once that I had to push the shoulder back a little. They were oversized, at least for the rifle chamber I was dedicating these cases to.
Here's my process,
1. Inspect for defects that cannot be remedied and remove those cases.
2. I debur the flash hole and uniform the pockets. I'm not sure the latter is necessary, but I do it out of routine and since I paid good money for the tool.
I guess I can justify this step since uniforming makes it easy to clean primer pockets in the future.3. I check the length and rarely, if ever do I have to trim but I check just to make sure.
4. I chamfer the necks inside and out.
5. Tumble to smooth the surfaces of the cases and remove surface films. It seems the mfg.'s process leaves a film on some brand of the cases.
6. I full size to remove neck dents, align the neck with the body of the case, and to produce a uniform inside neck diameter. I do not push the shoulder back* or extrude the case.
*I did encounter a lot of Hornady cases once that I had to push the shoulder back a little. They were oversized, at least for the rifle chamber I was dedicating these cases to.
bozo699
Gold $$ Contributor
I shoot more than 45 with RL-26 but I didn’t start there I worked up with Lapua brass I never tried 4831 but wouldn’t start there either, 45 grains of that size of powder is up unti the shoulder
Wayne
It will be off after 1st, and 2nd, and even 3rd firing.
There is more to a tune than muzzle velocity.
But with 1st firing you can run a max pressure test with new but culled cases.
2nd firing run full bullet seating testing.
3rd firing, run primer swap testing.
All at less than max pressure.
After that your cases should be stable and ready for powder testing -with best coarse seating, and best primer. You'll know what max pressure to stay below.
That’s the nice thing about Lapua brass . Take it out of the box, prime and load !Can't comment on 6mm creedmoor specifics just preparing new cases.
Here's my process,
1. Inspect for defects that cannot be remedied and remove those cases.
2. I debur the flash hole and uniform the pockets. I'm not sure the latter is necessary, but I do it out of routine and since I paid good money for the tool.
3. I check the length and rarely, if ever do I have to trim but I check just to make sure.
4. I chamfer the necks inside and out.
5. Tumble to smooth the surfaces of the cases and remove surface films. It seems the mfg.'s process leaves a film on some brand of the cases.
6. I full size to remove neck dents, align the neck with the body of the case, and to produce a uniform inside neck diameter. I do not push the shoulder back* or extrude the case.
*I did encounter a lot of Hornady cases once that I had to push the shoulder back a little. They were oversized, at least for the rifle chamber I was dedicating these cases to.
Fast14riot
Gold $$ Contributor
Same. Ive noticed that when fire forming AI if I push it too hard on first firing I'll have issues with the brass after 4-5 firings.
I believe this, where you will have to size at the webline (no choice).
It comes down to brass wanting to go where it's been. But you can ease into where you want it to go.
Small yield up, small size down, repeat to work harden as stable -where you want it.
The cases won't reach stable for a few firings anyway, so no need to rush it or ruin them.
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