Chamber Deepening Question

[tinkerfive]

Today was the 4th time now that I've set back shoulders and re-reamed a chamber deeper

to clean it up.

 

To be clear I'm talking about the 4th ( gun / barrel ) not 4 times on the same barrel.

 

It seems strange to me that all the cuttings I get are from the neck and shoulder area.

 

I have yet to pick up any noticeable cutting on my reamer from the body area.

 

It's understood & accepted that as hundreds of rounds are fired that headspace increases.

 

I can only surmise that chambers grow in diameter too, as well as in length.

 

Tinker

[z1r]

How much deeper are you cutting? .050", .100", 1/4 thread, 1/2, 1 full thread? If you are just trimming the shoulders some then most likely less than .050". Due to the body taper there is very little to be removed from the sides. If you move the reamer in .050" deeper you will likely only make the chamber .002" wider near the shoulder but even if you only deepen the chamber by .002" you HAVE to remove that much material and all at the front. Hope that makes some sense.

[tinkerfive]

How much deeper are you cutting?

 

Sorry, I didn't think to mention.

 

Others have mentioned "setting back a thread" enough times that

it didn't even occur to me to mention "how much deeper".

 

I was of the understanding that when you wanted to "clean up" a

chamber 'one thread' was the starting point.

 

So the answer the the question is one thread.

 

I've done less just to correct headspace.

 

This chamber was kind of ugly

so I went for the 'one thread' rule of thumb.

 

Tinker

[z1r]

One thread equals .083" so you still do not end up removing much metal. think of the reamer up to the shoulder as being sort of a pilot drill. As such, it removes the bulk o fthe material. the rest which makes up the body simply cleans it up. The further to the rear you go the less material that is left to remove.