So right off the bat this is my first AR home build and i may not describe everything properly so bear with me. I was putting my partially built upper unto my lower to get an idea of fit , so i slide the pins and and as im playing with my sorta assembled gun the pins fall out. I examined this and then examined my buddies colt that was next to mine and noticed that when i pushed on his take down pin there was a catch of some sort keeping his pins from sliding out and exerting pressure so they didnt slide around. I have a LPK and i can account for most of the pieces but i dont see anything that looks like it would hold the pins in place. so my conclusion is the following either : 1) im missing a piece 2) im doing something wrong 3) something is out of spec. Being as this was my first build i have no idea which one it is. help please! oh and while im at it my safety feels pretty gritty when i turn it , is it just new part break in or should i be worried? It works but it just feels rough. For reference the LPK and upper are from Accurate armory and the Lower is from PSA.
Parts 11 (detent spring) and 12 (detent pin) on both ends should be holding the pivot and takedown pins in place
If this is your first build and you don’t have an interesting memory of your front (pivot) detent pin rocketing off into space, then you probably did not install either the spring or the pin.
The rear (takedown) pin and spring are held in place by the buttstock or any spacer/plate you may have between the buttstock and the lower receiver. If the buttstock or spacer are not installed, they will simply fall out if the lower is oriented barrel-side up.
Hope this helps.
Ok so if im reading this right the spring gets inserted first and then the pin for both , then im assuming with the rear that the butt stock will exert pressure on it to keep it in place? I didnt lose any spring and or pins so either i didnt get it in my LPK or im staring right at it and dont know what it looks like. And thanks this is supremely helpful, especially for a first timer like me!
For the rear takedown pin, the detent goes in first, then the spring. It’s held in by the receiver end plate which is in turn held in place by the castle nut on the buffer tube. Managing that spring/end plate/buffer tube/nut along with the buffer detent/spring can sometimes make you wish for four hands during that part of the assembly.
The pivot pin…same thing. Detent first, then spring. THAT one can be tricky and it’s likely you’ll launch a spring or two getting it in there. The pivot spring/detent is the same as the takedown spring/detent. I’d recommend you buy a few extra.
After several years and many springs lost, finally bought a clever little tool from Brownells that makes installing that pin simple. http://www.brownells.com/.aspx/pid=26488/Product/PIVOT_PIN_DETENT_INSTALLATION_TOOL
As to gritty and/or wobbly selectors, I always found that to be hit-or-miss from LPK to LPK, and never found a good one until the BADASS. THAT is a well-made and well-designed accessory. Your safety will move and click smoothly and positively.
Watch this. You can find other videos on how to properly assemble your rifle. I personally do not use any special pivot pin tool to do this. I do use a very thin piece of metal to hold the detent and spring down while I insert the pivot pin. By thin metal, I mean something similar to one of those sparkplug gapper tools:
No offense, but that is not correct. Spring first, then pin.
Philip:
Take a look at this from TOS:
http://www.ar15.com/forums/topic.html?b=3&f=4&t=226782
For a video of a guy making the pivot pin installation seem obnoxiously easy, see:
http://video.google.com/videoplay?docid=-1683970245954810194#
I use a clevis pin to hold the spring and pin in place, but it ain’t that easy or sure. My advice? Put a bag in place to catch the detent pin when it launches, then try again. One thing I like about Stag LPKs is they include an extra detent pin.
Yup. I had safety selector in my brain as I was responding.Think before type. Think before type. Think before type.
Sorry for not getting to this sooner. Front pin assembly (pivot) is spring first, then pin. Rear (takedown) is pin first, then spring.
Thanks for the assist ill go back through my LPK and see if i can spot something that looks like it goes there. ill report back later.
the LPK should have consisted of this:
you can see the springs and detents next to the takedown and pivot pins
Thanks for the picture gotta get this thing out of the closet and look.
I second having a few extra pins/springs around. It makes life easier.