AR Build Question...

J

jwrowland77

New member
This is the first ever build I've attempted.

I picked up my lower today and ordered my lpk last night (Daniel Defense...I knew I would be picking up lower today). Well, I got to thinking that I really want to assemble every part on my rifle, so I started looking at Uppers an Stocks and what not. The reason I want to assemble every piece myself, is because I really want to know all the inner workings of my rifle. Mainly because, in case something breaks, then I will know how to disassemble it and repair it.

My dilemma comes in, is this a smart thing to do to completely assemble it myself or should I just buy a completed upper with barrel?

I plan on doing a flat top an M4 barrel an upper, collapsible stock.
 
My then-17 year old son wanted to build an AR for his HS graduation present.
Chose 6.5 Grendel and we sourced all the parts required.

Brownells has a very useful checklist, and online videos for assembly. The FFL that supplied us with some parts also recommended Glen Zedicker's book, which was very helpful as well.

My son had little to no experience with hand tools, at all...

Assembled it in one evening.

Many tools are convenient, but unnecessary. Requirements depend on build specifics. Pin punches, upper and lower receiver holders for your vise. Most everything else should already be in your toolbox. Double check all your parts lists- it's easy to miss something.

Do it and have fun, it's not rocket science.
 
tobnpr said:
My then-17 year old son wanted to build an AR for his HS graduation present.
Chose 6.5 Grendel and we sourced all the parts required.

Brownells has a very useful checklist, and online videos for assembly. The FFL that supplied us with some parts also recommended Glen Zedicker's book, which was very helpful as well.

My son had little to no experience with hand tools, at all...

Assembled it in one evening.

Many tools are convenient, but unnecessary. Requirements depend on build specifics. Pin punches, upper and lower receiver holders for your vise. Most everything else should already be in your toolbox. Double check all your parts lists- it's easy to miss something.

Do it and have fun, it's not rocket science.
Click to expand...

Yeah I found the brownells checklist last night, and printed it off. I have the lower and LPK should be sent tomorrow. I'll have to check those videos out though.

I bought a set of pin punches yesterday. The only thing that had me worried was the headspace. I assume though if I buy all the go/no-go gauges then I should be good to go.

I appreciate the responses so far. I'm leaning towards assembling every piece just so I can know all the inner workings. That type of stuff I just love.
 
As for headspacing:

Just put the barrel (with barrel extension on it) into a vise (with padded jaws) and then get your bolt and carrier group. CLEAN THE CHAMBER. Make sure there's no dirt or crap in the chamber - check it with a flashlight.

Put in the go gage. Put the bolt (extended out from the carrier) into the extension. Push forward.

The bolt should rotate closed completely.

Pull the bolt backwards. Pull out of the extension. Pull the go gage out of the chamber, wipe it down and put it back into the container in which it came.

CHECK THE CHAMBER again for dirt, dust, etc. Put in the no-go gage. Extend the bolt from the carrier and push the bolt into the extension again. Now the bolt should NOT rotate to full closure. You can tell this because the carrier will not be all the way up to the back of the extension - it should be sticking off the extension by 1/16th to 1/8th of an inch.

Pull out the bolt, pull out the no-go gage, wipe down and return to container.

You're done.

The only time I've seen this fail is when someone put on their own barrel extension and they did not torque the barrel extension down onto the barrel tenon with a torque wrench or the proper tools - which then allows a bolt to close on a no-go gage.

If you're putting on your own barrel extension, then get a proper extension driver to put into the flutes of the extension, and get a 1/2" drive torque wrench. The spec torque is 150 ft-lbs. Do not skip on this torque. Get your barrel into a proper vise with proper lead soft jaws, or you need to get some aluminum or plastic blocks around your barrel into a vise without soft jaws. If you're using plastic or aluminum blocks to hold your barrel in a vise, you might find that you need some powdered rosin to keep your barrel from slipping as you torque on the extension.
 
wyop,

Thanks for the headspacing write up. Doesn't seem to difficult. Just sounds like I need to make sure I get all the proper tools and follow instructions is all.
 
Checking headspace is always a good idea, don't get me wrong...

Our Grendel barrel came with a matched bolt, so it was unncecessary for us.

"Technically", as long as the barrel extension/chamber and bolt are within specs, headspacing would be fine, and a lot of guys do barrel changes without verification. Just a different animal...there is no way to adjust headspace anyway- short of removing the barrel extension and machining/re-chambering the barrel. Problems are extremely rare, just make sure to torque the barrel to spec.

I'd spend the money on extra ammo.
 
You're right - as long as the barrel tenon, the depth of the chamber, the barrel extension and the torque of the extension onto the tenon are within spec... the headspace issue on AR-15's is largely a non-issue.

The only time I become concerned is when people put on their own barrel extensions. That's it, really. And that's because we gunsmiths usually "budget" about .002" for the "crush" of parts when threaded together under torque. On a bolt action rifle, we allow .002" for "crush" when we thread a barrel onto a receiver, and I allow/budget for that same .002" when I thread an extension onto a barrel for the first time and torque it to 150 ft-lbs.

Edit: I'd be spending the extra money on reloading gear. I suspect that if these idiots in Congress can't get what they want on weapons and magazine restrictions, they'll broaden their gaze and start hammering on ammo availability - eg, no more mail order ammo.
 
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