Ring around the shoulder?

[only1asterisk]

A friend brought me a custom Springfield and several fired cases. The fired cases show heavy concave ring just below the shoulder. I take the rifle and cases and tell him I'll see what I can do. No visable ring in the chamber. Fired cases are normal with the exeception of the ring, but I was cautious. I necked down some 35 Whelen cases until the just would chamber and loaded them with fireforming blanks. Still the ring. Very odd. It isn't a step in the chamber, but more of a pinch. It's very deep, but I don't see what made it. Any ideas?

David

 

[Bwana John]

a custom Springfield

What kind of Springfield? what caliber? Im guessin a 03 in 06

 

[only1asterisk]

Exactly Bwana! That would be a slightly important fact I neglected! Turned down military barrel I think. Very nice stock. Not a bubba job at all.


Like the name!

David

 

[trapshooter]

I'd check the chamber dimensions first.

 

[Bwana John]

Try a casting of the chamber using "Cerrosafe" a low melting temperture casting alloy used any time a "positive" copy must be made of a rifle, shotgun or handgun chamber, neck, throat or bore. Then mic the casting using the specs for a .30-06 chamber.

 

[Jim K]

Sure the ring is not convex, looking like a second shoulder? That is the sign of a .308 chamber that has been reamed out to .30-'06. The .308 is wider at the shoulder than the .30 is at the same point, so cases fired in a rechambered gun have a "ring" just where the .308 shoulder would be.

Jim

 

[only1asterisk]

Jim,

It is concave and deep. It looks pinched.

David

 

[Jim K]

Can you possibly post some pictures of the cases? A concave ring down by the base indicates excess headspace, but one that far up is a new one on me.

Jim

 

[only1asterisk]

Jim,

I've seen rings from excessive headspace, but this new to me. Plus, I necked some down 35 Whelen brass to preclude any possibility of excess headspace and they did the same thing. Here is a picture of the factory load, it looks worse in person. The expanded cases measure fine.

 

[rbernie]

I wonder if the barrel was short-chambered when it was turned down. I guess the best way to tell would be to cast the chamber...

If you trim the cartridge to the minimum OAL, does the ring lessen?

 

[only1asterisk]

rbernie,

I thought about that. When I necked down the 35 whelen cases I trimmed them back to 2.475 which is .020 under max. The ring appears as before.

I have some cerrosafe on order that should be here in a couple of days.

David

 

[Jim K]

Hi, David,

I confess I have never seen anything like that. It looks like someone used a really messed up chambering reamer, or maybe tried to grind down one originally made for another caliber.

I can't see how the chamber could be cleaned up and still keep the rifle in .30-'06, so I can suggest some options. The first is to have the barrel set back a thread and rechambered. That would be my choice if everything else is OK and I liked the gun. Or a new barrel can be put on, a much more costly process. The third choice is to simply live with it.

If your friend doesn't reload and is not working the brass, and the rifle is OK otherwise (accuracy especially) he might just want to shoot it as is. I don't see any danger involved, just some odd looking cases.

Or (fourth option) he can trade the gun off and it will become someone else's problem.

Jim