The Case Head

[feelinducky]

I was at the range the other day and a guy was telling me the shinny mark on the case head was from not enough lube inside the neck while resizing. He said as you pull the case down over the expander you will actually bow the case head from the pull of the shell holder. Is this correct?

Thanks

 

[FearNoWind]

I was at the range the other day and a guy was telling me the shinny mark on the case head was from not enough lube inside the neck while resizing. He said as you pull the case down over the expander you will actually bow the case head from the pull of the shell holder. Is this correct?

Thanks

No, IMO, it is not correct. The expander ball in the die doesn't even come close the the case head and the amount of "pull" from the expander ball would be countered by the rim of the case not the case head.

If the case isn't properly lubricated over its entire length you can expect some scuffing on the web of the case when it runs into and out of the die.

I've never been concerned about those shinny marks on the web area of the case.
I do, however, examine fired cases for signs of case head separation:
http://www.realguns.com/Commentary/comar46.htm
Those shinny spots seem to me to be quite common.

 

[feelinducky]

Let me rephrase:

The shiny mark is on the face of the head after firing due to it hitting the bolt incorrectly, which is why he said the face is bowed. Sorry for not stating that important fact. Thanks for the reply

 

[dsculley]

In order for this to be the case, we would have to know that the bolt face is square to the chamber as in a bolt that has been trued. If the bolt is from a production rifle and has not been trued, then it could be that the case head is not bowed, but the bolt face is not square to the chamber causing the issue.

I agree with FearNoWind, I don't think the expander ball would put enough tension on a case to bow the head. If your expander ball is that hard to pull back through the neck then the neck has been WAY oversized by the die.

 

[Dosh]

Ducky, how about a pic of the spot on the case you refer to. Perhaps that would help others see exactly what spot is in question.

 

[FearNoWind]

In order for this to be the case, we would have to know that the bolt face is square to the chamber as in a bolt that has been trued. If the bolt is from a production rifle and has not been trued, then it could be that the case head is not bowed, but the bolt face is not square to the chamber causing the issue.

I agree with FearNoWind, I don't think the expander ball would put enough tension on a case to bow the head. If your expander ball is that hard to pull back through the neck then the neck has been WAY oversized by the die.

Perfectly stated, IMO.

 

[Jay Kyle]

Hard to tell without a photo.. if it's little round spot then it's case-in-ejector extrusion getting wiped by the bolt as you open it - but it's hard to tell

 

[J E Custom]

I was at the range the other day and a guy was telling me the shinny mark on the case head was from not enough lube inside the neck while resizing. He said as you pull the case down over the expander you will actually bow the case head from the pull of the shell holder. Is this correct?

Thanks

The dies have nothing to do with this marking of the case head.

Ejector marks on the case head are typically from hot loads. the pressure pushes the brass back in the ejector hole and make a small bulge in the case head. When the case is extracted the bolt rotates the case and shears this bulge off leaving the round shinny mark on the case head.

The hotter the load, the worse the mark. even a perfectly flat bolt face will do this if excessive pressures are reached.

J E CUSTOM

 

[feelinducky]

Thanks for the replies. I'll try to post a picture tonight.

I'm using regular Redding full length resizing dies, so I don't think I'm oversizing the neck

 

[feelinducky]

The Norma Brass is handloaded with 60.5g IMR4451. My chrono says its running 3211. I have 2 other pieces that have the same marks loaded with 60.0 and 61.0. Hodgdon website load data for IMR 4451 is 58.3-62.0g

The Winchester brass is a factory load with similar marks. Both have the primer crater.

Thanks for looking.

Remington 700 Action trued with a 24" Bartlien Barrel it is a tight chamber.

 

[Laelkhunter]

Thanks for the replies. I'll try to post a picture tonight.

I'm using regular Redding full length resizing dies, so I don't think I'm oversizing the neck

Don't think that sizing has anything to do with the pics you posted. Is the rifle a custom, or off the shelf? Does it do this with all ammo fired, or just that handload and that factory load?

 

[rdsewell]

I have to agree with J E Custom. Experienced this in the past myself.

 

[LoneTraveler]

I agree with J.E. Custom about it being over pressure. If the barrel is custom fit if the throat is short and either factory or hand loads are seating tight in the lands of the barrel you may getting high pressure with factory and hand loads too.

I have seen some ancient reloading dies that was neck reamed to tight have a problem of actually pulling the shoulder on a 222 Rem case till the neck looked like a milk bottle taper, When it came over the expander ball. The case gained about .020 in length and would not chamber in the gun.