Machined out an AR barrel last night.

[spitfire_er]

In preparation for an upcoming 6.5 Grendel build, I decided to re-hone my skills a little. I use to thread/chamber about 15-20 barrels/year, it's been a couple years since I chambered up a barrel. I have never done an AR barrel, and I decided to test out my lathe after a full restoration on the machine.

I had an old Rem 8 twist .223 700 barrel that had a bad throat, I chucked it up to see if I still had it! Everything turned out great and I think I'm good to go on the Grendel project. I'll see if this barrel can shoot at all and maybe use it for plinking or closer range varmints. I still need to machine the gas block and port, but that's the easy part IMO.

 

[rardoin]

Nice fish scaling on the ways!

 

[Shrek]

What lathe did you restore ? Did you scrape it yourself ?

 

[spitfire_er]

What lathe did you restore ? Did you scrape it yourself ?

An old South bend 10L. I had a machine re-builder regrind the bed and scrape it all in. I did the rest. I have my SB 13" too, but I have quite a bit more tooling for my 10L so I used it.

 

[hoz53]

In preparation for an upcoming 6.5 Grendel build, I decided to re-hone my skills a little. I use to thread/chamber about 15-20 barrels/year, it's been a couple years since I chambered up a barrel. I have never done an AR barrel, and I decided to test out my lathe after a full restoration on the machine.

I had an old Rem 8 twist .223 700 barrel that had a bad throat, I chucked it up to see if I still had it! Everything turned out great and I think I'm good to go on the Grendel project. I'll see if this barrel can shoot at all and maybe use it for plinking or closer range varmints. I still need to machine the gas block and port, but that's the easy part IMO.

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ive got a 12 twist from a rem 700v im going to do the same with. any 22 barrel i come by that i dont use for a bolt action or i take off one gets the AR treatment before going to tomato stake. what clearance did you set the barrel to breach?

 

[spitfire_er]

ive got a 12 twist from a rem 700v im going to do the same with. any 22 barrel i come by that i dont use for a bolt action or i take off one gets the AR treatment before going to tomato stake. what clearance did you set the barrel to breach?

0.010" clearance.

 

[Bogusname]

I did the same thing with a take off Remington barrel. Like you I just wanted to do it.

 

[hoz53]

0.010" clearance.

.010 seems to be what alot of people use and what i think would be good however some people set theirs as close as .002 because of what they call bolt slop. this is when the bolt slams forward and can push the case shoulder back if this dimension is to large. i think .002 in a semiauto might cause functioning problems- no room for crud ect- id like to talk to someone who sets this dimension so close(.002)- nice job on the barrel--

 

[spitfire_er]

.010 seems to be what alot of people use and what i think would be good however some people set theirs as close as .002 because of what they call bolt slop. this is when the bolt slams forward and can push the case shoulder back if this dimension is to large. i think .002 in a semiauto might cause functioning problems- no room for crud ect- id like to talk to someone who sets this dimension so close(.002)- nice job on the barrel--

I would agree with that. My thoughts were 0.010" gives you room for misc stuff like a shaving, a chunk of brass that broke off or if you jam a bullet and dump the powder or into your gun. I won't be rolling in the dirt, but 0.002" is tight to me especially in an auto. I feel 10 thou is a good number. Not sure what accuracy you would gain by using a tighter bolt nose clearance.

 

[hoz53]

I would agree with that. My thoughts were 0.010" gives you room for misc stuff like a shaving, a chunk of brass that broke off or if you jam a bullet and dump the powder or into your gun. I won't be rolling in the dirt, but 0.002" is tight to me especially in an auto. I feel 10 thou is a good number. Not sure what accuracy you would gain by using a tighter bolt nose clearance.

i dont know about accuracy but bolt slop may cause excessive headspace and early brass failure. Doesnt seem like alot of people have that problem with the .010 figure. I try letting the gun feed them then eject the unfired round to see if headspace has changed. Zediker is one of the people who advocate the .002 figure. i will contact him to find out how its worked out. Thanks