First,I'm not an expert. I'm just another opinion. Disagree if you want.
If we were discussing an overbore cartridge,(7mm STW,257 Wby,6mm-06,etc)
I'd be more open to an overcharge of appropriate powder being the problem
But in a more balanced cartridge,like 308 and 223, loading density (with appropriate powders) 90% or more.
If that charge is 42 gr,then 4.2 gr more would be approx. 100% fill.
IMO,it takes some determination,or at least inattention,to seat a bullet in a 100% full case.Yes,we must ay attention. A Powder Cop die, a cleverly mounted magnifying dental mirror, a camera,or just a determined eyeball can monitor case fill. Good idea.
"That bullet seating operation did not feel right" Checking it out is a good idea.
We are using "at least once fired" 2016 Lake City brass?
Unless you shot the new loaded ammo or bought new brass,brass history is open to question. Who removed the primer crimp? If the OP did,I'll buy it was once fired.
If you were sold "Once fired processed" brass ,realize it was likely fired in a machine gun. You don't know the headspace condition of that machine gun.
A serious "stretch ring" case thinning is possible.
That could cause a catastrophic case failure.
High pressure along with case failure might be what happened.
Sure,we can get overpressure by overcharging,to the point of locking a bolt or blowing a primer
But,for the sake of a theory,lets say pressure was fairly high due to military brass. The "margin of error" was thin.
A catastrophic brass failure can be destructive
But as Columbo might say "There are one or two things that bother me"
Looking at the three fired sample cases,I see no brass extrusion into the ejector hole. I see no primer cratering. I think I would see those with a batch of overpressure loads.
And I don't think brass failure would crach the bolt face abd open up the bolt firing pin hole.
IMO,this is some serious overpressure,and I question see it happening with any amount of 4895 you could inadvertently seat a bullet over.(my assumption,unproven)
I'd lean toward it being a pistol powder contamination,whether the powder measure held one charge,or the measure was not fully empty ,or a powder container was contaminated.
But,what do I know?
If we were discussing an overbore cartridge,(7mm STW,257 Wby,6mm-06,etc)
I'd be more open to an overcharge of appropriate powder being the problem
But in a more balanced cartridge,like 308 and 223, loading density (with appropriate powders) 90% or more.
If that charge is 42 gr,then 4.2 gr more would be approx. 100% fill.
IMO,it takes some determination,or at least inattention,to seat a bullet in a 100% full case.Yes,we must ay attention. A Powder Cop die, a cleverly mounted magnifying dental mirror, a camera,or just a determined eyeball can monitor case fill. Good idea.
"That bullet seating operation did not feel right" Checking it out is a good idea.
We are using "at least once fired" 2016 Lake City brass?
Unless you shot the new loaded ammo or bought new brass,brass history is open to question. Who removed the primer crimp? If the OP did,I'll buy it was once fired.
If you were sold "Once fired processed" brass ,realize it was likely fired in a machine gun. You don't know the headspace condition of that machine gun.
A serious "stretch ring" case thinning is possible.
That could cause a catastrophic case failure.
High pressure along with case failure might be what happened.
Sure,we can get overpressure by overcharging,to the point of locking a bolt or blowing a primer
But,for the sake of a theory,lets say pressure was fairly high due to military brass. The "margin of error" was thin.
A catastrophic brass failure can be destructive
But as Columbo might say "There are one or two things that bother me"
Looking at the three fired sample cases,I see no brass extrusion into the ejector hole. I see no primer cratering. I think I would see those with a batch of overpressure loads.
And I don't think brass failure would crach the bolt face abd open up the bolt firing pin hole.
IMO,this is some serious overpressure,and I question see it happening with any amount of 4895 you could inadvertently seat a bullet over.(my assumption,unproven)
I'd lean toward it being a pistol powder contamination,whether the powder measure held one charge,or the measure was not fully empty ,or a powder container was contaminated.
But,what do I know?
Last edited: