barrel machining processes

wayne · 12-12-2014, 01:20 AM

I have a good friend that's a machinist and has built a few AR BARRELS and a few savage. He says it's easy just buy a rifled blank cut thread grooves and breach and a few other things. He is a great machinist but don't want to buy a blank and have it shoot lime ****!! Is it real that easy??? Opinions?

wayne · 12-12-2014, 01:21 AM

And I am doing a 5.45x39 so not a lot of options to go with!! Does bore need lapped or anything else done to it?

**bootsmcguire** · 12-12-2014, 01:30 AM

As a machinist myself, I can tell you that getting the bore perfectly centered all the way down is the most important thing when cutting a barrel. If that is off in your setup, then the whole thing will be off.

As for lapping that is totally up to you. Is it needed? No. Does it make for easier cleaning? Yes. Does it guarantee better accuracy? Not really.

wayne · 12-12-2014, 01:34 AM

So even if the bore and rifling is cut you can still mess it up easy?

**mscott71** · 12-12-2014, 05:28 AM

Originally Posted by wayne

So even if the bore and rifling is cut you can still mess it up easy?

If he's a great machinist and knows how guns work, then go for it. There is a bit to knowing how things work to make the job successful. I'm not even close to a great machinist, but have muddled my way through making and chambering a handful of barrels and all have turned out good so far. As boots said, setting up to be as close to perfect as possible is the key. You need your chamber to be straight into the bore and you need your action threads to be straight as well. Your order of operations can be important as well. I cut the threaded tenon before chambering just because I'm thinking removing material from the outside of a blank could open up the inside slightly. Don't know if it does, or is worth worrying about, but that's me.

Did you buy a chamber reamer? What brand of blank? Is this for an AR15 or bolt gun? I do this stuff for fun, but with the dwindling prices on AR barrels I would just buy one if possible.