I need pointers for building an AR.

K

kgs

New member
I am about ready to start building my own AR-15 from a kit. I bought a Bushmaster upper and stripped lower and I have all the necessary parts to complete the rifle. Why did I decide to buy a kit instead of a factory assembled rifle you ask? Well, I thought it would be a cool little project and I figured it would be a good way to really get to "know" the rifle.
Anyway, the upper is already fully assembled from the factory and really the only thing I have to do is put together the stripped lower receiver. I hear that the trickiest maneuver in the process is the installation of the pivot pin spring and detent. What other tricky operations can I expect? And what other advice can you guys give? BTW, I have either bought or made myself, the proper tools needed to perform this job.

Thanks much.
 
Hope this helps

kgs,

First task: acquire ALL the necessary drift punches! These can be had at your local hardware store if you know the roll-pin diameters. OR you can go to http://www.bushmaster.com/shopping/gunsmith/stapnchset.htm
to purchase the punches.

Building up an AR15 is very straightforward and could be fun, especially if the upper has already been assembled for you. Even if it hasn't, with the proper tools the assembly of an AR15 is quite easy.

Assembling the lower is very easy. What you've heard concerning the pivot spring detent is true. If you purchase an amorer's wrench then this is very easily accomplished due to the built in "jig." However, when I put mine together, this wasn't the case. Although it is not recommended, what I found to work was to actually cut down the pivot detent spring. Trimming the spring doesn't require you to cut it in half, but enough to where you can easily manipulate the detent and front pivot pin in place. What I did was cut it far enough to where about 1/3 of the pivot detent was in the channel. From there, it was very easy to install the pivot pin. Keep in mind that by doing this you lose spring tension in the front pivot pin. As to the cons of doing this, I'm not sure if there are any. Mine hasn't shot lose or fallen apart on me at all, and I know of a few people that have done the same as well.

However, the front pivot pin was of my least concerns. What scared me the most was installing the trigger-guard pin. This is the pin at the very end of the trigger housing nearest the pistol grip. I have heard many tales of do-it-yourselfers that have actually broken off one of the "ears" of this area. I advise you to be VERY patient when doing this. What I did was actually take a file and add a slight "bevel" to the end that will be going in head first. This aides in "setting" the pin and when driving it through to the other ear, if out of alignment will self align itself (depending on how aggressive the bevel). I also added some lube to cut down on friction, and to make the drive home to the next ear easier. Also, make sure that you rest the lower, especially the ear on a block of wood, that way you have equal and opposite forces being exerted on the second ear. You do not want all the force of the punch to be on one side, you want there to be an equal force as to reduce the risk of breaking one of the ears.

I've tried best to explain the situation that is going on here, however, it seems a little messy. Perhaps another forum member could bail me out on this?

If you have any more questions, you can email me directly. Look into my profile for my email address.

Hope this helps,
Jim
 
Kgs: Get a Brownell's catalog. They have loads of stuff, and I bought their roll pin punch set. I too will build an AR....someday. Meanwhile, I shoot the Bushy AR carbine.
 
You must log in or register to reply here.
Back
Top