Need pointers on milling an octagon bbl

[PaulH]

I've got a .308 bull bbl and I'm giving some thought to making a sporter weight octagon. I know NOTHING. Nothing in my gunsmith books. Side milling, end milling? Numerous light cuts? Fewer medium cuts? Temperature control? How many holdown points for 22" finished length. Any tips for avoiding stress warpage? And so on, because actually I don't even know enough to ask the right questions. One thing I can say with confidence, time means nothing on this project. I would like to end up with a round section of 3/8" or so abutting the receiver...just for looks.

 

[Cadillac]

That would be a tough job I think. I would buy hex material then bore centered. Drilling a 22” long hole is gonna be tough without the proper tools. Gundrill bits come to mind but I don’t have a clue on the subject.

 

[PaulH]

Ummm, guess I didn't make it clear, I propose to mill a completed ROUND rifle barrel with eight flats to produce an octagon barrel. External cuts on a rifle barrel.

 

[Cadillac]

That’s gonna be a tough cookie to do. I see the barrel turning into a banana with the cuts. Stresses will release when cut. In making the barrel it is already shaped then bored not the other way around. I have two Henry rifles with octagonal barrels love em. Good luck!

 

[lordbeezer]

Light cuts. Side milling. Index often.

 

[derf]

You don't need a rotary table or an indexer to flute or cut flats on a barrel. I made up some hex nuts for both ends of the barrel and use them for indexing. Clamp the barrel down directly to the mill table, use a coupla 5/8" dowels pressed snuggly into the T slots for a locating stops, and another positive stop on the end of the barrel. A 22" barrel should be rigid enough with just clamps on each end.

Use a mister or flood coolant if you have it. If you don't, set up a shop vac to pull air through and around the barrel. Index your cuts opposite of each other.

 

[PaulH]

Derf, Thanks...sweet setup with stuff I can make. Simplicity rules.