Bruno has 6mm barrels in stock. The XP action is a great base to build an accurate gun on. Are you planning on building a competition gun or just a prairie dog popper? What stocks are you looking at?
all my guns have "glued in" actions so I can't test fit with the action while the barrel is in the lathe. All my actions are from BAT machine. Bruce (from BAT) made me a gauge utilizing the same cnc program that he made the action with. I use that to check the threads. Once the threads are cut I use the floating reamer holder with the Lambeth/Kiff reamer stop and ream until it stops cutting. Drop in the go gage and check it with my indicator. Done with the chamber. The longest part of chambering a barrel is dialing it in. Sometimes I can do it in 20 minutes, sometimes I give up after an hour and go in the house and watch tv. The next day is usually better. I have a spider on the back, and a 6 jaw on the front. I wrap the barrel with a #8 copper wire where the 6 jaw bites. I use Best-Test 50 millionths indicators to zero the first inch and a half of the tenon. (after I cut the first inch off the barrel blank) I have 3 sporter class rifles and 1 unlimited rail gun. I do 20 to 24 barrels a year for myself and several a year for some friends.
I’m not sure how he does it but this is how I do it. I short chamber let’s say .050 short of being head spaced. I’ll ream another .03 leaving roughly .02. I’ll check with feeler gauges let’s say I nailed it and I’ve got .02 more to go. I’ll push the tail stock forward until the reamer bottoms out in the chamber . I’ll crank the tail stock feed forward a few turns to make sure the reamers actually bottoming out. I’ll lock the tail stock down and turn on the lathe. Feed the reamer .01. unlock the tail stock and slide it back. clean the reamer and chamber and check my head spacing using the action, feeler gauges and my go gauge. Now I’ve got .01 more to go. I slide the tail stock back checking my headspace again using the action, feelers and go gauge. The measurement should be .005 now. I’ll slide everything forward again bottoming out reamer out. crank the tail stock forward a few times and lock the tail stock down (making sure to take any backlash out) I’ll zero the tail stock dro turn the lathe on and ream forward .006 or maybe .007. Check the head spacing using only the action and the go gauge. if the handle falls it should be head spaced. I’ll check it with a no go gauge or a go gauge with I piece of tape on the back of it. Once I put a dro on the tail stock I’ve never used my reamer stop again. I hope that made sense to you.
That is a sound method. I do have one concern. That is the 100 thou cut. I dont know what caliber you are chambering for but I have found that 50 thou is about the max depth of cut before the flutes on the front of the reamer start to get packed. (over the years I have messed up 2 chambers by going too far and galling them) I do 50 thou for the first few passes and then I drop down to 30 thou to finish. I have the reamer stop set to my chamber size (6mm PPC cartridge) and I keep going until it bottoms out against the back of the barrel. I flush out the chamber and use my go gage to check. I rough up the chamber with some 320 or 280 (what ever is handy), I break the edge on the back of the chamber with the same paper, turn the barrel around, crown it. (90 degree cut) I have to confess that my barrel marking process sucks. I write the date and any other info (hard spots in the chamber, gummy when cutting threads, etc) on the barrel with a marker and the put clear tape over it. Then I head to the range.
I mis-read your post. You said nothing about how far you go when roughing the chamber. Sorry about that.
ok that works. 99% of the barrels I chamber are the same caliber (6 ppc) and for the same family of actions (BAT). They all have the same tenon size and the same headspace.
That action has a large loading port. What caliber are you making it? I have a friend that has an action with a very large port. When he opens the bolt, he places the new cartridge in the front before removing the old one behind it. ( we shoot 6 ppc 1.5 inch case length) ) There is a feeling by some that an ejector only "adds complexity" to a gun. I believe that the BAT actions are the best available today. Good luck with that build.
