Improving a chamber with a hand reamer...
 

Has anyone used a hand-held reamer to cut an improved chamber on an existing chamber? I've seen it done on one of my guns and it worked fine, but I want to try it myself and wondering if I have the skills. :o

I have seen a couple gunsmiths do it, by hand. They took it slow and easy, checking often for the fit of the improved/fired cartridge that they had also.
So I guess a person could attempt to do it. All you loose if you goof is another barrel or someone set back and clean up the spoiled chamber. Bill K :)

I don't know if you have the skills, either. I have done it on a few (5) rifles and they all turned out to be great shooters, not that I have any special skills - at all.
Just go slowly, and remove and clean chips from the reamer and from the inside of the barrel, every 1/8" to 1/4" or so. I used a lot of "Rapid Tap" as well.
I clamp the barrel in the bench vise, vertically, with enough clearance to use a cleaning rod in the bore each time the reamer is removed. I put a pad of towel on the
floor to catch lubricant and chips.

I did my 22-250 to a 22-250AI...
 

But as we all should be aware an Ackley chamber needs to be.004” shorter than the factory chamber.So unless you don’t want to fully clean the chamber up you will need to have the barrel set back a bit.At that point you might as well have a nice new barrel threaded.It was fun to do on my used Ruger Varmint and the gun is accurate,but I stopped a little short to preserve the original headspace in my chamber,the 40*shoulder is there but it has a tiny step which to me is ugly.
I did it as an experiment to see the velocity gains I could get going to an Ackley chamber.My full intention is to have it rebarreled professionally when I get some more funds.Another option is to go to a bigger Ackley case so you can fully clean up the chamber,like in my case I should have ordered a 22-243 Ackley.
Matt

Good reply, Matt.

A chamber can be AI'ed without setting the barrel back, and most will shoot very well. The issue is the increased head space for the cartridge from simply reaming an existing chamber which can be accounted for (~99%) by proper die adjustment.

However, doing it that way might be an issue for a new owner if you ever decide to sell the rifle. For me the simplest and most bullet proof method is to set the barrel back and to clean up the entire chamber with the AI reamer.

Doing it that way, no new owner will be surprised when he sets the AI sizing die properly for his press and has case head stretching/possible separation with the cartridges fired.

JMO - BCB

Many .22 Hornets have been hand reamed to improve.

For clarifcation purposes, that is indeed true. But "improving" a 22 Hornet to a 22 K-Hornet is not the same concept as "AI'ing" a chamber when head space is to be considered..

-BCB

I have always thought and been told that when every you re-work a chamber, in any manner, you should always keep and check headspace in mind. Bill K :)

100% of the time........ With any chamber, head space is paramount for safety and efficiency.

That said, simply reaming an existing Hornet chamber to get an improved K- Hornet chamber is not the same type of process as truly "AI'ing" a chamber.

-BCB

For every chamber I re-cut by hand, I necked up the cases, then necked them down for proper headspace BEFORE they were fired. I never fired 'factory' ammo in them, thus there was no need to set the barrel back the normal requisite .004".