Thread: Tips on reaming a chamber

Well my reamer turned up today for 22k hornet. Im contemplating doing it myself. I am a little bit familiar with reaming, valve guides, king pins suppressor bushings, ird is this process much different. I know dont turn the reamer backwards and use plenty of lube any other tips?

Practice first on a barrel off-cut. Then check your results with a borescope.

This is a finishing reamer so not sure about doing a full cut with it?

@blip are you bumping up an existing 22 Hornet to K Hornet ?

Chamber reamers are really not reamers at all
They are actually a form cutter because all parts of it are cutting all of the time

There are a lot of different ways of cutting a chamber
Lots of pros and cons

Is it a live pilot or solid pilot reamer ?

You are doing this in a lathe, eh? It's not something I would personally do by hand (though by no means impossible)

I assume it's a fluted jobby, not a d-bit?

Hog out as much as you can ahead of time with drill/ cutting tools. Ream to final size. "Let the tool do the work" aka "don't force it" I use rocol cutting oil but flood coolant would work equally well. Pressure-flush coolant even better again.

Don't drop the reamer. If you think you might Don't work over a concrete floor!

Originally Posted by akaroa1

@blip are you bumping up an existing 22 Hornet to K Hornet ?

Yep k-ing a hornet live pilot premium finishing reamer

Originally Posted by blip

Yep k-ing a hornet live pilot premium finishing reamer

Well I would hand cut it with the barrel muzzle down in a vice with protected jaws,
Relatively small tap holder as your driver
Take the live pilot off the reamer and check that it will slide through your bore with some reamer oil.
You don't want it too drop through like a stone or it might be a little small.
If it sticks in the bore then just make another one that is a fraction smaller.
Neatsfoot oil as your cutting oil
Clean the reamer every 20 gentle turns ( air gun is good into a plastic bucket ) and blow down the bore into that bucket
Don't load it up and you will get a feel from where the swarf is and what it looks like.
Clean the bore occasionally to see how it is looking.

Use the force
Just let the reamer do the work not you pushing it around
Reduce the force gradually as more of the reamer is doing the cutting

Take your time and good luck

I re cut a 223 Howa new old stock barrel a couple of weeks ago to 222 Rimmed
The barrel was being stubbed into a Contender barrel shank and I was able to set it back a little
I have cut quite a few chambers on the lathe but when I looked at the numbers and that the live pilot would be well engauged into the rifling and because the bulk of the chamber was already there.
I hand reamed it and it was very easily done.
@blip your 22 H to KH should be a breeze

I use a floating holder and ream chambers in the lathe to about 90% depth, taking great care to ensure bore is perfectly true before starting. I also drill a pilot hole first (about 75% of the chamber) to reduce work on the reamer. Go slow, use lots of oil and withdraw and thoroughly clean the reamer frequently. Finish the chamber by hand, and only 5-6 revolutions before cleaning. I fit the barrel at about 98% chamber depth, break the chamber edge carefully, then headspace with a reamer extension.

Thanks for the info guys its along the lines of what I was thinking, Plenty of oil and let the reamer do the cutting. I dont think it will take much out of the chamber and will basically follow the existing chamber anyway?

Well the rainy day project was to ream the first of the hornets to a k. Pretty straight forward just went real slow and plenty of oil and cleaning as I went. Now I need a dry day for a test fire

Had a gap in the weather today so took it for a test run. Shot well. Had some left over hand loads ppu brass had a few reloads but went well. I also had some factory s&b that I tried as well, had 1 split at the shoulder The same as my grendel started doing. Could be something to do with hard brass that some people have mentioned. Might have to anneal it.