Is headspace all that critical?

F

fishbone

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My Harrell neck/shoulder-bump die came loose in the press. Till it was corrected, I formed 7 rounds with 0.012" head space instead of what produces bolt fall of half free/half resistive.
I fired them during a WU session at a match Sunday. Five of the rounds made a hole smaller than a clicker ball point pen. At a different aim point the next 2 would have printed...one in the same spot as the 5-group and the seventh a shade off.
While using a jam seating, does the head space become less important, other than over working the brass?
I know this isn't a comprehensive test, but does lend itself to some thought.
Any thoughts or experiences?
 
fishbone said:
My Harrell neck/shoulder-bump die came loose in the press. Till it was corrected, I formed 7 rounds with 0.012" head space instead of what produces bolt fall of half free/half resistive.
I fired them during a WU session at a match Sunday. Five of the rounds made a hole smaller than a clicker ball point pen. At a different aim point the next 2 would have printed...one in the same spot as the 5-group and the seventh a shade off.
While using a jam seating, does the head space become less important, other than over working the brass?
I know this isn't a comprehensive test, but does lend itself to some thought.
Any thoughts or experiences?
Click to expand...

I believe consistency, consistency and consistency is what forms small groups. Having said that, I also believe that at neck/shoulder-bump die leads to brass that will never be as consistent as brass formed with a full length sizing die because only part of the case is ever brought back into its original dimension. Couple that with inordinate headspace and the only thing I would ever use a round like that would be as a fouler. Nix the neck/shoulder bump die for a full length sizing die each time you reload, and you'll be headed in the right direction ... from the start.
 
Unless you want to be on the third page of a two page match report, every thing in this game is important.

Plus, excessive headspace, just 0.010" or so can be dangerous. This causes the case body to stretch and, over time, if the back of the case pulls apart, poof, right in your face.
 
I must have missed something here. I thought all of Harrell's dies >were< full length dies that adjust the shoulder as well as properly size the case. I know a lot of us call them bump dies, but that's not what mine are. Also, if the die came loose, it is looser, not tighter, which seems to me, didn't move the shoulder back at all. This wouldn't give you more headspace. It would leave the shoulder just like it was fired the last time. So, what did I miss?

Rick
 
I'm not suggesting 0.010" head space as a workable thing. I used the 0.012" case as an example (extreme) where it had no ill effects.
You are right on the loose die, Grayfox. That had me scratching my head. The lock ring was loose as well which backed off allowing the die body to turn deeper into the press. Not something I could picture happening, but it did.
My thoughts are to try 0.002" to 0.003" head space. I wouldn't expect that to stretch the cases too much.
 
fishbone said:
My thoughts are to try 0.002" to 0.003" head space. I wouldn't expect that to stretch the cases too much.
Click to expand...

You might try the short-range Benchrest norm of .0005" to .0015", with .001" being the goal. Do not size over .002".
 
I have heard of fellows that intentionally push the shoulders of their .220 Russian cases back quite a bit, and then turn down past what will be the neck shoulder junction, and with quite a bit of neck tension, and bullets seated at jam or a bit more, fire form. They do this to prevent doughnuts, something that I don't worry about, given that my bullets never get close to that part of the case.
 
fishbone said:
The lock ring was loose as well which backed off allowing the die body to turn deeper into the press. Not something I could picture happening, but it did.
My thoughts are to try 0.002" to 0.003" head space. I wouldn't expect that to stretch the cases too much.
Click to expand...

The lock ring backing off and letting the die seat deeper is what I had assumed in my comment above. As to 0.002/3 shoulder setback on brass fired in that one chamber,that is about right for hunting loads for that one gun. But 0.002/3 is a bit too much for maximum shoulder setback in a benchrest setup.
 
Boyd Allen said:
I have heard of fellows that intentionally push the shoulders of their .220 Russian cases back quite a bit, and then turn down past what will be the neck shoulder junction, and with quite a bit of neck tension, and bullets seated at jam or a bit more, fire form. They do this to prevent doughnuts, something that I don't worry about, given that my bullets never get close to that part of the case.
Click to expand...

Boyd, this is commonly done by those shooting shortened .30's in Hunter BR (30X44, 30X46, etc.) where cases are made by shortening various 308W and 300 Savage parent cases. I do my 30BR's that way using a shell holder faced off .020. Perfect blend, no donuts.

Good shootin'. -Al
 
Fishbone My 2 ¢

There was a sight misunderstanding from the get go on your post :confused: POST #2 from abintx was correct in what he said about the brass stretching, however, this does not pertain to your set up because the die you are using is a FULL length die, not just a bump die. This is what I mean when I say we have to be PRECISE in this game, especially when typing questions. POST # 3 from Jerry. I agree completely as you would be surprised how much harder, moving the shoulder back/forth a few extra .000, is on the brass, dangerous. POST #4 from Greyfox picked up on the type die but in your response (POST # 5), seem like you may have missed that. The reason you went to the Harrell 3.0 die was to give you a touch more sizing in the body area. I concur with abintx, Boyd & Jerry in their subsequent posts 6, 7 & 8. .:confused:
 
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