I don't tumble my brass.
Got a bulge...
- Thread starter Gregg C
- Start date
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Something I noticed while making these measurements.. I'm not pushing the bullet down into the neck very far. In fact there is only about .130 of shank holding it in there, and the brass makes an hour glass shape below it. Below the shank, the neck measures .361. Not sure that means anything....
Hugnot
Well-Known Member
My astute analysis of this ongoing situation is:
Squashed brass!
The brass needs to be trimmed. The brass might be within specs for trim length, but the chamber might be too short.
The neck looks plastered with crud like powder & primer residue. This is the result of jamming excessive length brass into a short chamber. Upon firing the brass neck is prevented from expanding because it is jammed into the chamber neck/leade. A flared neck end is evident with a thin shiny area indicating contact.
Powder gasses including primer residue & residue & other gush back along case body to bolt face resulting in messy firing(s).
Additional doings that would support the excessive length idea are powder smudged brass sides & powder residue on bolt face.
I respectfully submit that your brass needs to be trimmed shorter and after firing the brass necks should be nice, clean & shiny.
Squashed brass!
The brass needs to be trimmed. The brass might be within specs for trim length, but the chamber might be too short.
The neck looks plastered with crud like powder & primer residue. This is the result of jamming excessive length brass into a short chamber. Upon firing the brass neck is prevented from expanding because it is jammed into the chamber neck/leade. A flared neck end is evident with a thin shiny area indicating contact.
Powder gasses including primer residue & residue & other gush back along case body to bolt face resulting in messy firing(s).
Additional doings that would support the excessive length idea are powder smudged brass sides & powder residue on bolt face.
I respectfully submit that your brass needs to be trimmed shorter and after firing the brass necks should be nice, clean & shiny.
Not saying this can't happen but I would think you would have to be slamming the bolt shut to do that to brass.
You can see he has a pretty good chamfer on the outside of the neck and the leading edge is pretty sharp, I would think it would roll that edge back first.
But Hell trim off .020 on a case and see what happens
Hugnot
Well-Known Member
Nope - forceful compressive forces exerted by camming action of bolt lugs upon closing bolt with bolt handle. A view of bolt lugs would show leading edges slightly angled to initiate camming action upon bolt closing.
Lotz of the new bolt action rifles having plastic stocks & big scopes have long bolt handles - leverage.
Lotz of the new bolt action rifles having plastic stocks & big scopes have long bolt handles - leverage.
It's possible the trim guide (or whatever the thing is called that goes in the case mouth) is slightly expanding if it's tight.
I would seat a bullet and see if it corrects the slight expansion during the seating step before I would lose too much effort on troubleshooting.
I would seat a bullet and see if it corrects the slight expansion during the seating step before I would lose too much effort on troubleshooting.
Man .013 is alot of clearance if your measurements are correct i can't imagine Tubbs designing that much, I would call him Monday a.m.
No expander. Anneal every shot.
I just looked at Tubbs print he does have a neck of .376.
I may call them anyway, .009 isnt that much, is it?
No it isn't, my math was screwy.
I did it on a sized case not loaded.
I have did it on a saami rifle with .010
Bolt closes with normal pressure. This particular chamber is new... 12rds thru it as of today. Cut by the same smith with the same reamer as the last barrel, which got 500 rds thru it before removal. I don't think this bulge is forming in the chamber. I think I'm inducing it some how in my sizing process. Wild ES is what prompted me to go to a smaller bushing, looking for more and consistent neck tension. Looking at the loaded neck today makes me think I need more bullet shank in neck to provide more gripping surface. Been wanting to move up to 300gr bullets, anyway. After I run 50 or so rds down this tube, I start load development .
Mikecr
Well-Known Member
IMO, your clearance and sizing is too high, and I don't know about your annealing.
What you have is more like re-forming than normal bushing sizing.
Large angles are set in motion with excess sizing. This, leading to rolling of brass into forms different than expected.
I know Tubb is big into huge clearances. I had one of his 'roll Royce of dies' for my T2K in 6XC.
Worse die/chamber combo I ever ran into, as it plagued me with stuck cases. Basically big clearance chamber, super small die combo..
If I were you, even without this particular issue, I'd toss the barrel and Tubb dies, and start over with another reamer.
What you have is more like re-forming than normal bushing sizing.
Large angles are set in motion with excess sizing. This, leading to rolling of brass into forms different than expected.
I know Tubb is big into huge clearances. I had one of his 'roll Royce of dies' for my T2K in 6XC.
Worse die/chamber combo I ever ran into, as it plagued me with stuck cases. Basically big clearance chamber, super small die combo..
If I were you, even without this particular issue, I'd toss the barrel and Tubb dies, and start over with another reamer.
