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.

