Getting serious, chambering Qs

[Ryan in SD]

Next on the horizon is getting tools necessary for chambering (5.45)

Advice requested!

I've done some research and am thinking about getting the bald eagle floating reamer holder.

I am pretty much confined to doing this on a CNC since the manual lathe we have cant turn threads anymore and I want to do threads and chamber at the same time.

Im open to suggestions:

bore gauge rod: I have been using drill rod and turning down an end about 1.5" to fit into the bore when I cut crowns. I then indicate the end of the protruding drill rod with 2 indicators to get everything trued to the bore. I imagine I can use the same method to find and adjust bore true for chambering.

Reamer: This is where Im a little lost. I was thinking of using tenth pins to figure out the bore dia and getting a finnish reamer with the right pilot.

Reamer holder: I was thinking of using the bald eagle reamer holder and peck reaming, fully cutting the chamber with no roughing. Just slowling going in .200" at a time. I saw some videos, I think this is the most cost effective way for me.

I dont plan on doing more than a handful of barrels a year, so i dont want to hear of costly options.

[ar15barrels]

Dial in your barrel.
Drill out the majority of the chamber 0.050" undersized to within about 1/16" of the shoulder length.
Bore the rear 2/3 of the chamber depth to a couple thousandths under the diameter at the shoulder.
That will force the reamer to align properly as the floating holder lets it go where it wants.
It will also significantly reduce the amount of metal you need to remove with the reamer.

[Ryan in SD]

That sounds like a good idea. Thanks.

[kcstott]

Yep nothing wrong with the set up and yeah I'd drill and bore out as much as possible to keep the life in the reamer.

The other thing is take advantage of the coolant system on the CNC.