Building my first AR, from scratch

[ab_bentley]

I have not built an AR prior to this. For the pure learning it provides I decided to build one. I started with a very inexpensive 80% lower and milled it out. Afterward I decided it needed to be hot pink, IO can't stress enough the color it came out to be wasn't what was pictured, laser pink is the most neon color I have seen. Next I had a 223 Remington 700 take off barrel sitting under my bench, so I face it off and found that when you remove the bolt recess you only have to re-chamber roughly .075" to be right a spec. which is very nice. I cut 60's on both ends and turned the shank down. From there I threaded the shank. I set up in the steady rest and headspaced and finish chambered the barrel. I then cut a 29* cone in the breech .570" wide to facilitate feeding. Then I flipped it over and crowned the barrel. I also had to turn the shank down to 1" for the lock ring to slip over the barrel. The last picture is of me opening the gas block from .625" to .700" so I didn't have to contour the sporter barrel, just the seat for the block. This week I will cut the seat and install a rifle length (12") gas tube. I am still waiting on a few parts so I might not be able to finish it this week. Thus far I believe I have $275 into the whole project. It has been fun and all I can say is those people who think slapping an upper on a lower or torqueing a barrel to an upper is gunsmithing, you're wrong. Anyway I'll keep posting pictures,

Adam

 

[nicholst55]

Have you drilled your gas port yet? Being neither a machinist nor a gunsmith, I was always told that you contour the barrel, then drill the gas port before doing anything else. Ideally the gas post must be located in a groove, although that's not always the case with factory barrels. Just curious what your take is on it.

I also thought that Duracoat colors like Hot Pink required a white base coat, but then what do I know?

 

[jscandale]

I can absolutely tell you from several years of experience and many many AR barrels down the river, some of them in the winners circle at the National Championships that there is ABSOLUTELY no relevance to accuracy of barrel life if the hole is in the groove or the land. Believe it or not, the barrels that have the hole half way in both the land and groove exhibit the least amount of erosion looking through a bore scope.

JS

 

[chuckbuster243]

I can absolutely tell you from several years of experience and many many AR barrels down the river, some of them in the winners circle at the National Championships that there is ABSOLUTELY no relevance to accuracy of barrel life if the hole is in the groove or the land. Believe it or not, the barrels that have the hole half way in both the land and groove exhibit the least amount of erosion looking through a bore scope.

JS

I could not agree more John. I think that the in a "land" or in a "groove" is just the way that it was taught and thats what people keep doing. They have just never strayed from that. I am with you on the half on half off... What you say is true. I just put mine where they land and go shooting... They shoot better than I do so it is negligible. Matt

 

[ab_bentley]

I have more pictures from today. I drilled the gas block (burr free) and I nailed it right on the land and groove. I am of the camp that a split hole it the best, but again it's all from reading as this is my first AR.

Adam

 

[Phil]

HOT PINK..........

Adam, are you sure there isn`t something you are wanting to tell us...........


Nice job.....

Phil.

 

[nicholst55]

Okay, I'm glad to know that there is no 'real' reason to drill the gas port in a groove. I guess that's one of those things that just keeps being repeated, so it must be true!

BTW, Mr. Bentley, very nice work!

 

[ab_bentley]

Sssssstop it you silly gooses!

It's an attention getter, that's why I went for it.

Adam

 

[ab_bentley]

Well finished it up today, well as much as machining goes. I had to turn the gas seat (PITA) and then I torqued the extension on. I set it up in V Blocks and leveled it, used a pin to find top dead center and then moved down until I hit the mark I transfered to drill the port. I used a center drill to peck the starting hole. Then I started with the .060" drill bit and moved up to .073", bur free and right centered on the land and groove. After that I used the barrel spinner and cleaned up the barrel.

Now I just have to paint and test fire.

Adam

 

[ab_bentley]

Well after much debate I think I am going to have a hacking session tomorrow. I think I am going to chop the barrel down to 18".

We'll see.

Adam

 

[ab_bentley]

Well I shot the upper today. I was pleasantly surprised, it cycled soft and smooth with no hiccups. The brass ejected fine and didn't hit the deflector. This was with a CAR buffer, tube, and spring. I didn't have optics on it so I don't know the accuracy of the barrel.

I also left the barrel @ 23".

Adam

 

[chuckbuster243]

Glad it shot well for you... Its nice to have a project come together! Matt

 

[ab_bentley]

I had to abandon the pink one for now, put too much paint on it on critical areas. But I present the Franken-Stoner.

Adam

 

[jscandale]

Betcha couldn't have done it without that McDonalds coffee on the bench

JS

 

[Valar]

Nice job got me thinkin I should start one. I need to finish up my .243 project first. This looks like fun Im going to start looking for a 223 takeoff barrel. Maybe i can trade the Rem 243 Takeoff barrel I have for one? Regardless been wanting to try milling a receiver casting. Looks like a fun project. I have had real good luck with factory Rem barrels after lapping them. Rem makes a good barrel but hand lapping seems to really help them allot with copper fouling that robs accuracy. Thanks for Posting.

 

[ab_bentley]

Well at the time that picture was taking I ddin't know that I damaged the crown on the barrel. I couldn't keep a 4" group @ 100yds. I took a look at the crown and sure enough the little carbon star was missing a leg or two. I put it back on the lathe this morning and put a new crown on it so now I just have to test fire it.

Adam

 

[Hoier]

This is a wesome thread! Let us know how she shoots with the new crown.

 

[ab_bentley]

Well it shoots, pretty well too. The three shot group (circled) is from factory Hornady SP bullets and the rest is a mixture of blasting ammo my dad loaded. I think it's a keeper.

Adam

 

[ab_bentley]

Some goods reloads and presto.

Adam