Brass undersized by .020” :(
- Thread starter Mram10us
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25WSM
Well-Known Member
You should have no shame in setting up dies according to the manufacturer instructions. Die companies except whidden should be ashamed that their instructions suck butt. What a disservice to up and coming reloaders to give instructions like they do. In a perfect world where everything is made perfect it would work. But rifles are definitely not part of the perfect world equation. I'm glad you know how to do it now and figured your brass were short. I would do a false shoulder and try the cow method on a few and see if it is going to blow them up enough. It really should get you very close will no barrel wear and no bullet cost.
Shep
Shep
Case separation at the case head or in the body.
Brass can be damaged on the first firing when a rifle has excessive head space. But most times the new brass has been annealed correctly & there is no issue, as it fire forms to the chamber.
Some put light oil on the case to fire form. This keeps the brass from sticking to the chamber walls. I have not tried it.
Its said to increase bolt thrust? Not a good thing.
A .014" head clearance caused my 223 brass to separate in the middle of the body. My Dillion RL-450 progress press gave a different shoulder bump at each station. 3 good rounds- 1 bad each cycle.
25WSM
Well-Known Member
I always use light oil on my cases when fireforming. Since your not supposed to run hot loads when fireforming it doesn't hurt having more bolt thrust. You lose alot of pressure when that brass expands to the new chamber. The oil let's the brass slide back to the bolt fast so only the front of the case is stretched. I anneal before and after fireforming also.
Shep
Shep
I think these are valid points it just puzzles me why a die manufacturer would instruct in this manner. I've been at it since 2008 and have loaded thousands of rifle loads with very acceptable accuracy out to 300 yards. I know, big deal but with some cartridges (.25-06, 30-06, .308) I've gotten multiple cycles out of brass with seemingly no ill effects. No annealing, etc. The guns are still as accurate as they ever were, some more so. Maybe it's just that I have never shot far enough or in enough volume for the bad effects to elucidate themselves?
25WSM
Well-Known Member
You were probably lucky a bunch of your died were close in size and so you didn't see the effects of over sizing them. Obviously your new die is cut way too short.
Shep
Shep
I think so too, Shep.
My first bushing dies instructions said to start with a .010" gap between the shell holder & bottom of the fl die. Took forever for a sized case to chamber. I called Redding and ask what i get if both make contact. They said standard SAAMI sizing.
My 7mm TCU die would set the shoulder back to much if both made contact. Was not a SAAMI standard.
"A tolerance is the acceptable difference between the maximum and minimum size of a mechanical part as a basis for determining the accuracy of its fit with another part."
Most times the dies & rifle chambers are both near the middle of the tolerances. Not maximum, not minimum.
But put together a maximum chamber & minimum die, this leaves a lot of head clearance for the cartridge sitting in the chamber. Not a good thing.
Standard dies give a safe usable sizing 99 % of the time when the shell holder contacts the bottom of the die. Imo.
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25WSM
Well-Known Member
Safe sure but definitely not optimal.
I used to cut all my Chambers dead nuts on the go guage. About 50 percent of the factory dies would not move the shoulder no matter how much cam over you gave it. And then I had to cut the bottom of the did off about .005 to get them to work. So now I just make all my Chambers .003 deeper and most dies work now.
Shep
I used to cut all my Chambers dead nuts on the go guage. About 50 percent of the factory dies would not move the shoulder no matter how much cam over you gave it. And then I had to cut the bottom of the did off about .005 to get them to work. So now I just make all my Chambers .003 deeper and most dies work now.
Shep
In the particular case I was referring to the cases had been fired in my Daniel Defense Delta 5. They had a fired shoulder dimension of 1.582". When I followed the RCBS 1/8 to 1/4 turn past shell holder contact setting, I bumped to 1.565". Even when I backed off to shell holder contact, I was bumping .004 to .005.
Imagine that!?
