Chamber flaw need help please

[lar45]

Hi all, I rechambered a SMLE in 308 win a few weeks ago and I just got it back. The chamber was too fat and too long, I set it back a thread and used a reamer and gauges from reamerrentals.com. I turned the reamer by hand and went until it would just close on a factory round. When it closed on the go gauge, it would not close on a factory round. I thought it turned out pretty good and the test fired cases looked good.
But I didn't notice a light line near the shoulder. That's why it's back.
I hope these pics are clear enough.
http://www.lsstuff.com/temp/308-chamber-01.jpg

http://www.lsstuff.com/temp/308-chamber-02.jpg

The ring is only on one side and is smaller than the rest of the case.
If I measure the ringed side, it's .455" and 90 deg from that it is almost to .456" on my dial caliper.

I haven't pulled the barrel yet to get a closer look, but I think it's on the bottom of the chamber.

I'm guessing that the rechamber didn't clean up all of the old chamber, so the smaller step near the shoulder is what the reamer cut and the fatter part just behind it is what's left from the oversized factory chamber.

So what do I do to fix it? Any suggestions?
I already sent the reamer back, but I guess I could set the barrel back another thread and recut it again? Or would 2 threads be too much and cause an unsightly gap between the barrel and stock?

I'm thinking about turning a brass rod to fit the chamber and put lapping compound on one side to try and polish out the step. Maybe cut a case in half to insert and protect the good side, then just try to hone out the step?

I'm open to suggestions.
TIA.

[richbug]

Looks to be about the same as one thread on an SMLE. Apparently the Indians used a fatter chamber reamer than the one you rented. I am no expert, but I'd just lap the chamber to make the line disappear.

If you look close there is a line in the neck too, same distance as the shoulder.

rich

[lar45]

Ya, a much bigger chamber. It was splitting cases with factory ammo. I measured a bunch of facotry and military stuff and the mil stuff is slightly bigger at the base. I think with the military brass being thicker in most cases, is why it wasn't splitting cases with mil surplus ammo. ???

I think I'll take a chamber cast and then lap it and check again with another chamber cast.
I've got some 320 lapping compound that I think should work well.
Then go shoot it when I think it's good enough.

The part I didn't like about cutting the new chamber is that the cases bulged at the base when I was done. The chamber was cut to exactly what the reamer was, it's just that factory ammo is much smaller.

[slughammer]

From the looks of the pic, the old chamber neck was real fat too. It almost looks like the brass was roll crimped. Is the new neck concentric with the old neck? or is that just part of the old throat?

[Morgan Astorbilt]

Just lap it out. This was a problem when I was re chambering 7mm Re. Mag's to 7mm STW. The original reamer was just an elongation of the original body taper, and I told the owners NOT to fire their guns prior to sending them to me. Firing would expand the chambers just enough to show a ring where the 7mm Rem shoulder started. Couldn't feel it, but it was visible on the fired cases. Had to polish them all out. Later, the specs. for the STW was changed, reducing the taper to clean up the chamber.

Something to think about: The fact that it's only on one side indicates one or both chamber cuts were off center.
Morgan

[grumpy one]

Because your problem is on one side only, it won't lap out without giving you an assymetrical case form. The lapping process will basically tend to remove a fairly consistent amound all the way around the chamber. That means you won't be able to neck size and get accurate results with the finished rifle. FLS cases will chamber easily, but will expand assymetrically each time you fire them.

I'd have thought setting the barrel back another thread and cutting a clean chamber with a good reamer is the way to go if you are trying for an accurate, technically-correct rifle.