Gunsmithing Rebirth of an old AR barrel

[McLarenross]

I had an old 24" bull barrel left over from when I build an AR-15 Space gun for NRA across the course matches. The barrel shot decent but I got into other types of matches and the upper has sat unfired now for 4-5 years. Now I have a sickness, I cant leave things be, and I own a lathe. So I decided to make that old upper into a 3-Gun upper.


First thing I did was chop it off to ~18".





I got to use my new front spider chuck for the first time for this project, wow those 20tpi adjustment bolts make it easy to indicate a bore.



So after indication I turned the muzzle down for the 1/2x28 threads.







Now I stared to reprofile the rest of the barrel. For this I moved it out over the bed and used my 3-Jaw on the barrel extension and the muzzle in the live center. I turned the entire barrel to 0.750" with a small piece for the gas block to seat against at 0.875" That was a massive amount of material to remove. Thank God for power feeds.



After profiling I moved back to the spider and re-indicated and turned a crisp crown with a razor shard tool I ground just for this.



And here is what she looked like after all was said and done.



I didnt weigh the barrel before and after but I easily took half the weight off of it. Next project is a muzzle brake from the cut off barrel stub.

 

[Ultraman550]

I love these kinds of threads. To be able to literally build your own rifle is probably extremely gratifying.

 

[Delta4-3]

Good looking crown you have there sir, and I like the chuck, did you make it?

 

[McLarenross]

Thank you Delta. Yes I built it myself. I posted a thread about its construction. Its maybe a page back currently.

 

[E. Bryant]

Nicely done - looks like you did a great job in repurposing the tube and kept it from serving duty as a tomato stake.

I've performed a bit of barrel profiling in my home shop, and learned that it's not particularly easy or fun turning.

 

[Gene Poole]

Wow, that's a lot of turning without a follow rest. Did you have to do something to avoid chatter?

For the crowning, did you just use the compound and a super sharp bit, or was it a form tool?

 

[McLarenross]

I fully expected the barrel to chatter when I go to the middle but I guess the machining gods smiled upon me cause it never once so much as squeaked. Finish is as good at then ends as the middle. I used the compound set to 30* and turned from ID to OD with a super sharp HSS bit to make the crown.

 

[427Cobra]

I see my tax dollars were well spent