The throat problem

[semtav]

I successfully made an accurate chamber slug from my rifle using techniques I learned here I think. I trimmed the neck off a piece of brass and filled it with lead. I chambered it. I cast a the heaviest "ie longest" boolit I had for that caliber and pushed it down the barrel with a steel rod "I protected the rifling by wrapping the rod with 2 inch masking tape to bore diameter every 2 inches" once the rod and boolit contacted the case, I hammered the rod until it bounced sharply. I ejected the case and gave the rod a few gentle taps and out came the chamber slug, exactly the right size and able to be saved for future reference. No more guessing what is going on! You can see and measure every little detail. Hope it helps!

[Longwood]

Thanks Goodsteel.

That will help immensely.

I am obviously new here and am very slowly working my way through the archives but thankfully there are plenty of nice helpful people here that are pointing me in the right direction.

[Longwood]

Also thanks to semtav

[nanuk]

Semtav: what are those rings around the lead just above the brass?

are those the lube grooves from the boolit you used?

[semtav]

Yes, I don't have any smooth sided slugs (yet)

[Longwood]

I used the rod and soft slug to see what my chamber looked like. There was, repeat was, no throat. The rifling ended with a sharp chamfer right at the case mouth. It now ends at the same place but it now has a nice tapered leade into the rifling.
I bought a used reamer from Larry Gibson and I now have a perfect throat and PP bullets chamber beautifully. I doubt seriously that I will need to modify it more.
The reamer is now on the way to NY state and will be going to New Mexico next.