They're not all perfect, and at times, these little imperfections are annoying if not damaging. For those wishing to replace the stock trigger guard with an aftermarket trigger guard, here are instructions for removal of the stock triggerguard without damaging the lower receiver. Use masking tape all over the working area. When you go to put the new pin in, use a punch, from the other side, to help keep the TG lined up until the pin gets started in it.
On the front of the lower, drop the last takedown spring into the hole. I often chuck up a small punch and polish the outside using emery cloth. Don't be shocked if you send a few detents flying. Get a 2x4, drill a 3/16 hole in it at leat 1/2 in deep, position the lower over the hole with the pin in the 2x4 hole - drive out pin with punch from other side. It's installed correctly (I just need to drive it in flush with a punch). Back up the receiver, especially on the trigger guard, and also rear sight windage knob (the screw is easily bent). While a staple for many AR-15s, roll pins are not hard to work with, but a misstep could be catastrophic enough to permanently damage your AR-15. I then went to remove the other pin, and that's where I really ran into a problem.
When that didn't work, I tried a small nail that I had filed the point off of, but that didn't work either. 130″ roll pin to start the roll pin into the hole. Solution is to never use a DPMS kit. You'll notice that there are punches of varying lengths used in the work shown.
For a basic build, you'll need #s 1, 2, 3, and 4. Holding them together, install the grip screw. So, I tried a few things - I tried using a small allen wrench that I could get in there, but couldn't get enough force on it without damaging the wrench itself. Choose and use the right punch. See, now that wasn't so bad — right? Place the bolt catch on top of the spring and plunger. Place one of the detents in that hole followed by one of the springs. The long parts of the trigger spring need to fold back to give spring tension. Trigger Guard Assembly. For the lower parts kit, there really isn't much difference between all of the options out there. The shorter ones are a little easier to operate but the longer ones are necessary for some installations, simply because they give clearance beyond rifle parts you don't want to accidentally mis-hit with a hammer, or have the larger diameter handle portion in contact with a rifle receiver. I like to start with safety and grip. If you torque or twist the pliers it may snap the pin or the ears of the lower. Tell us how we can improve this post?
DPMS kits have large bolt and trigger roll pins. This lets the roll pin drop down into the punch a short way and makes installing it a lot easier. I'm not trying to talk anyone into banging on their guns, but there certainly may be times when a part replacement is in order, and something really simple, like replacing a bolt catch with something from the aftermarket, requires little more than a small collection of tools and a little insight into the process. This can also be done without the aforementioned punches, but they do make it easier and prevent misalignment of roll pins.
With a 1/8″ roll pin punch and a hammer slowly and carefully drive the roll pin out through the ears. Buffer and Spring Assembly. The Rear End: let's install your safety, grip, rear takedown pin, and receiver extension. Line up the hole in the trigger with the lower of the two trigger pinholes. I oriented backward at the setup but quickly realized the error when I pulled the pin out. Xanadu & neilfj--worked like a charm: I put my C-clamp in a vise, held the receiver where it needed to go, and did about 4 turns at a time (mainly because the electrical tape kept slipping), but you can see it did the trick. Steel pins going into aluminum holes make life way harder on the holes than the pins. Bolt Catch Assembly.
Cleaned up the bur in the guard with a drill bit, and it went in smoothly. Wear safety glasses! Actually, just read the responses again, after a cup of coffee, and want to clarify--I'm NOT trying to crimp closed the roll pin, what I'm trying to do with the C-clamp is provide slow steady pressure on the top of the roll pin to drive it in further, right? This is everything left over at this point. Chad is an absolute treasure trove of information about the AR platform, and as builders, we are fortunate to have someone as passionate and knowledgeable as Chad to reach out to. Wiggle the takedown pin so that these are lined up. Knowing the difference between these helps in a moment. Set the punch with the roll pin against the lower so that the cutout part of the punch is facing the lower. One that's too large may also deform it, and won't ultimately enter the pin's hole to seat the pin-end correctly. I use slightly more than the bare minimum tools because a couple of small upgrades makes everything a lot easier.