Preparing For My First AR15 Build and...

RLinNH

Sergeant of the Hide
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Minuteman
Mar 23, 2019
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I have my "Builders Set", LPK, and my trigger. Ready to build my first lower. I was going to follow the Midway USA videos, but I am looking for some literature that is a little more up to date. No I AM NOT saying that Midways video series are out of date. I am saying that they were made a few years ago, and things change. So, can anyone here point me in the direction of some recent literature or an online source that will walk me through building my first AR15 lower?
 
YouTube probably has a bazillion videos. Some are better than others. What brand lower do you have? The Aero Precision M4E1 is easier to assrmble due to having a threaded pin instead of a roll pin as well as having a built-in trigger guard.
 
What exactly do you think has changed? I think the only thing that's changed when I built my first AR back in the late 90s early 2000s is handguards and the advent of drop in triggers and for those two things you should follow the manufacturers instruction instructions or some generic video
 
Some words of advise/wisdom.

Use a 1 gallon plastic bag to install the front pivot pin. The use of a 1/4" clevis pin makes it fairly easy

Use the correct punches, especially the bolt catch specific ones

When installing the hammer, make sure the selector is on semi if installed already. If not, you will more than likely not be able to seat the hammer pin. The trigger will not have enough movement to allow it.

You DO NOT need to hammer the trigger/hammer pins in. You should be able to use the handle of a screwdriver or a plastic hammer to TAP them lightly if necessary, maybe just the hammer pin all you need to do is just get it past the "j spring"

Remember once you push the hammer or trigger pin in and have maybe 1/8" or so still sticking out--LOOK AT THE OTHER SIDE TO FLEX THE HAMMER OR TRIGGER TO ALIGN THE PIN IN THE OPPOSITE RECEIVER HOLE. Otherwise, you do what most do, get out a hammer and try to make another hole.

While not necessary, the use of a slave pin with the disconnector and trigger really helps. You can make one from an old hammer/trigger pin, cut to .625" and bevel the edges. Or for $225 +/- US, Geisseli will send you one with their super fan boy triggers.

Pay attention when doing the receiver extension (buffer tube) so you don't ruin the threads by allowing the end plate to contact the lower until the Re is indexed and you slide the end plate into place. What will happen is the end plate will hit the receiver allowing the tab to engage the lower and the inner tab of the end plate will gouge the RE threads. Happens on disassembly as well.

Don't worry about installing the rear take down pin, detent and spring until you have the RE threaded in. You rotate the RE 1/8 of a turn past tight and then install those three pieces, once in, rotate the RE back to index, slide end plate up and tighten the castle nut/lock ring. Spec is 40 foot pounds. The cheap RRA wrench from Brownells will not get you there.

STAKE THE CASTLE NUT, sure Joe bob will chime in and say he's never done it and it's never loosened, meanwhile he's still on the same case of ammo from 1975 and has 900 rounds left.

Hope this helps!
 
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YouTube probably has a bazillion videos. Some are better than others. What brand lower do you have? The Aero Precision M4E1 is easier to assrmble due to having a threaded pin instead of a roll pin as well as having a built-in trigger guard.

That's exactly what I purchased. An M4E1 Builders set lower and upper.
 
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Some words of advise/wisdom.

STAKE THE CASTLE NUT, sure Joe bob will chime in and say he's never done it and it's never loosened, meanwhile he's still on the same case of ammo from 1975 and has 900 rounds left.

Hope this helps!

I have never staked my castle nut in the 10 builds or so that I've done.

On my go-to, reliable, "expensive-for-me" build I was trying to mess with some part or another and applied torque that shouldn't have done anything to the buffer tube. My buffer tube moved. I checked- it wasn't "loose" in the traditional sense, just should have been staked like all those old guys told me from the get-go....
 
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Nothing changed on the AR assembly except what handguard you are adding on...even that doesn’t matter too much unless it’s a KAC Mod2...where the barrel nut is integrated into the handguard...to me. That’s a dumb design but whatever.
 
Some words of advise/wisdom.

Use a 1 gallon plastic bag to install the front pivot pin. The use of a 1/4" clevis pin makes it fairly easy

Use the correct punches, especially the bolt catch specific ones

When installing the hammer, make sure the selector is on semi if installed already. If not, you will more than likely not be able to seat the hammer pin. The trigger will not have enough movement to allow it.

You DO NOT need to hammer the trigger/hammer pins in. You should be able to use the handle of a screwdriver or a plastic hammer to TAP them lightly if necessary, maybe just the hammer pin all you need to do is just get it past the "j spring"

Remember once you push the hammer or trigger pin in and have maybe 1/8" or so still sticking out--LOOK AT THE OTHER SIDE TO FLEX THE HAMMER OR TRIGGER TO ALIGN THE PIN IN THE OPPOSITE RECEIVER HOLE. Otherwise, you do what most do, get out a hammer and try to make another hole.

While not necessary, the use of a slave pin with the disconnector and trigger really helps. You can make one from an old hammer/trigger pin, cut to .625" and bevel the edges. Or for $225 +/- US, Geisseli will send you one with their super fan boy triggers.

Pay attention when doing the receiver extension (buffer tube) so you don't ruin the threads by allowing the end plate to contact the lower until the Re is indexed and you slide the end plate into place. What will happen is the end plate will hit the receiver allowing the tab to engage the lower and the inner tab of the end plate will gouge the RE threads. Happens on disassembly as well.

Don't worry about installing the rear take down pin, detent and spring until you have the RE threaded in. You rotate the RE 1/8 of a turn past tight and then install those three pieces, once in, rotate the RE back to index, slide end plate up and tighten the castle nut/lock ring. Spec is 40 foot pounds. The cheap RRA wrench from Brownells will not get you there.

STAKE THE CASTLE NUT, sure Joe bob will chime in and say he's never done it and it's never loosened, meanwhile he's still on the same case of ammo from 1975 and has 900 rounds left.

Hope this helps!
KAC doesn't stake their castle nuts FWIW and everyone knows they only make rifles for hard core operators who run their weapon systems downrange.
 
Man...I must not be operating hard enough to stake my castle nut...

I do put blue loctite on the castle nut but I do not stake...and torque it to spec...that is if I do not run a PWS ratchet castle nut....

Yeah, on the rare instance I build something with an adjustable stock (2 of 5 builds so far) it gets the PWS Castle nut & endplate.