drilling popple holes in nitrided barrels

[openclassterror]

Just wondering if anyone has done this. I have a 5.25 XDM, and I noticed when I threaded it for a comp that the material is really hard and gummy about .02 deep from the nitride. Nearly impossible to cut with HSS, used carbide. I am thinking that if I drill a popple hole, it will push a gnarly burr into the bore, and a reamer will not peel it out since the interior of the barrel is also nitride. Thinking about pecking the hole in with a 1/8 carbide end mill. Any thoughts from someone who has fought this?

Tom

[openclassterror]

Ok, so I am not the most patient person in the world. After I got the last customer outta my shop for the day, I set it up in my mill. 1/8 carbide ball end mill cut great! Started at about 2K rpm, dropped it to 700 as it started to break thru because it began to chatter. Looked Beautiful! Re-assembled with the comp, test fired into the bullet tube, still a little up-n-down. Opened up to 3/16. Used a ball end mill again, but had to drop all the way to 450 rpm to keep it from chattering. Still no burr though! Muzzle flip is just about non-existent now. So, now the next guy knows! Sharp carbide ( I used TiAln coated), low rpm, steady pressure. Make sure to keep the chips clear so the cutter doesn't rub.

Tom

[stardust tommy]

Thanks for sharing this info, I'm not a machinist but I've got a milling machine at home...

[wes777]

Just wondering if anyone has done this. I have a 5.25 XDM, and I noticed when I threaded it for a comp that the material is really hard and gummy about .02 deep from the nitride. Nearly impossible to cut with HSS, used carbide. I am thinking that if I drill a popple hole, it will push a gnarly burr into the bore, and a reamer will not peel it out since the interior of the barrel is also nitride. Thinking about pecking the hole in with a 1/8 carbide end mill. Any thoughts from someone who has fought this?

Tom

The GUNSMITHING forum would have been better for your query.