Assembling a AR lower

[Miss Debbie]

How difficult is and what tools do I need to assemble an AR lower? I have the lower parts kit and buffer tube.

 

[Mags]

You need a punch and a wrench for the castle nut on the buffer tube. That's it. You can use pliers and/or a flat blade screwdriver on the castle nut but you could screw things up easily that way.

Oh yeah depending on your pistol grip you may need either an allen wrench or a screwdriver, just depends on your hardware.

 

[Zerodefect]

http://www.ar15.com/forums/topic.html?b=3&f=4&t=226782

 

[bpl]

There are good instructions on AR-15.com.

Example: http://www.ar15.com/forums/topic.html?b=3&f=4&t=226782

 

[FTSESQ]

Here you go:

http://www.ar15.com/content/guides/assembly/lower/

Best resource out there for assembling an AR

 

[Miss Debbie]

Thanks mags for reply pistol grip is Magpul and parts kit has a hex screw end, on castle nut how much force does it take to tighten it? And what is stalking?

 

[DBR]

There is a torque spec for the castle nut. IIRC it is about 30 ft #. For us normal humans, use a proper wrench - they are not very expensive - tighten the nut up firmly and back it off a couple of times to seat the threads then tighten it until you feel it stop solidly. Don't use Loctite but a light coat of oil on the threads helps with the "feel".

Keep the stock on the extension tube and use it to hold the tube from twisting while you tighten the nut - look from the back end to keep the butt plate aligned with the lower.

Staking is displacing a small amount of metal from the steel plate into the notches in the nut. This keeps the nut from rotating. You can usually get two of the notches where you can get at them with a punch. I use an automatic center punch. You can use a standard punch but if you've never used one before I recommend getting someone with some experience to do it for you. It is easy to make a mess of the plate edge.

Be careful when you clamp the lower to hold it while you tighten the nut. It is easy to damage the lower. I use rubber faced jaws in the vise and only tighten the vise enough to just restrain the lower.

 

[sig228]

The ar-15.com instruction as well as the Brownells videos are pretty much all you need.

Here's a link to the videos (section 7 is all about the lower assembly):

http://www.brownells.com/.aspx/lid=11004/guntechdetail/How_to_Build_An_AR-15_Video

Good Luck!!

 

[Quentin]

I built my first lower last year and found it very easy using the Brownells videos (print out their PDFs too if you want) and AR15.com guides. Brownells does push their own tools but for one build you don't need them. I did buy a good wrench for the castle nut and a front sight adjustment tool from Bushmaster since they're good to have around.

Otherwise just used standard tools I already had. Never needed a vise but did use vise grips with tape wrapped around the jaws to install the trigger guard and bolt catch roll pins. (Be very careful with the trigger guard, people occasionally break off the receiver tabs when installing that roll pin.)

The Brownells tool to install the pivot pin detent would be handy but you can buy a $1.50 clevis pin at a hardware store that does just as well (same diameter as the pivot pin). Otherwise you can just be careful and not use a tool (but should put a clear plastic bag over the lower to catch the pivot pin detent and spring because they likely will fly out a couple times before you get the hang of snapping them in place).

One thing, make sure you identify all the small parts so you don't mix up the bolt catch spring and disconnector spring, etc. I would leave the roll pins till last since once they're in they're in. Make sure the trigger and safety operate properly and don't drop the hammer so it hits the receiver/bolt catch - catch it with your thumb when testing the trigger.

Take all the time you need, think it out and you'll do fine. A lot of people say they do it in 25 minutes but that's too fast for the first time. Who cares how long it takes as long as it goes well.

 

[hatchetbearer]

I did my first one a week ago in about 45 minutes, I was taking my time looking at how stuff interacts with another. i think the hardest thing i had trouble with was keeping from binding the selector detent spring while installing the pistol grip. Have fun and take your time, a good punch set is a killer item to have.

 

[GeorgeF]

Try to get a good roll pin punch set - the kind with the ball tip on the edge of the punch. This really helps the punch from slipping off and scraping along the firearm, thus scratching up the surface.

 

[Tirod]

I did mine with a set of vice grips. The front pivot pin needs no special tools, one of those links shows how to slip in the detent, and use the pivot pin itself to depress it while putting it in place. It went so fast I wonder why the military instructions with a tool are even used.

Pressing the trigger guard pin in with vice grips goes easier than pounding on a special set of punches. The pliers are more readily available and can be used for lots of other things. Pin punches have one purpose and can't be used for anything else. For the occasional assembly of a firearm or two, punches really aren't an investment, they are an expense, which is what any tool is. No sense buying tools that can only be used one time, or for one thing.

Check to see if the handgrip screw threads are chased fully. Some shops stop short of threading them thru and the final turns are exceedingly heavy. It can strip the screwhead.

The bolt stop spring hole is blind, make sure it's clean and won't hang up the detent.

Following the instructions and taking your time, it's still only an hour to assemble the complete lower. It's quite simple and straightforward, the less brute strength or hammering, the better.

 

[nalioth]

Don't forget the pillow case.






It's hard to imagine those little springs can fling stuff so fast they disappear from this reality . .