First off, I'm using Winchester brass with some cheap Remington large rifle primers I found. (already have 2 duds in 15...they suck) I am using Unique under toilet paper and a case full of COW up to the neck, then plugging it with paraffin wax.
I started off at 10% of a full case load, only 3 grains. (not sure why only 30 grains Unique fit) Nothing at all happened at 3, at 4.5 I had a slight rounding of the shoulder, but the case wasn't much wider. 5 grains was about the same. I jumped up to 7 grains and it got better, looked like a Weatherby shoulder. Kept getting slightly better until 9 grains when it looked about fully formed. Going to 10 grains didn't do much more. Looks like the only way to get the final sharpening of the shoulder will be to fire with bullets.
Tyler, I think it would be more productive to just load a real bullet on some suitable powder, and go have some fun. I fireform live loads for my 243ai and 260ai, and both shoot 1/2moa, and run at standard cartrige velocities. I take them out for shots at crows or porkies, or just targets. It's good practice. If you were using somthing with shorter barrel life that consumed gobbs of powder then I would say, go stuff oatmeal!
Tomorrow I'll be doing the same. Yes those Remington primers suck.I can get I bet 50 grs of WW760 in a case.( Of course with a bullet that would turn my rifle into a bomb) so 10% ? that's 5 grs and that didn't cut it for you. I wonder if I used a magnum primer?
How does it profit a man if he gains the whole world but loses his soul?
What is WW760 shaped like? I'm not sure wh only 30 grains of Unique fit, it seems to me the little discs should pack tightly. So I guess I'm actually using 33% of the case capacity. No pressure signs though. I think the headspace is set a little long, with the case in the chamber sometimes the firing pin has to push the case into the chamber all the way, then the second time is fine.
I think the headspace is set a little long, with the case in the chamber sometimes the firing pin has to push the case into the chamber all the way, then the second time is fine.
And then the third time.
Looks like the only way to get the final sharpening of the shoulder will be to fire with bullets.
If you were to take Cowboys suggestion, Use a bullet to fireform with, seated long to hold everything snug on initial firing, you will end up with a better job the first time around. A pound of unique is about the same price as a used full set of rcbs loading dies. After which you can potentially form 70,000 brass with. Your misfires are coming from the unsupported case slopping around in the chamber, with enough slop sometimes that the firing pin is not long enough to reach. If still insistant on shooting blanks, at least size up a caliber and then partial necksize back down to create a false shoulder to hold your cases back against the bolt.
The words sometimes, and headspace too long can't go in the same sentence. Sometimes, and brass too short, now that works.