Lower Parts Kit with Extra Parts?

Joined
Jun 24, 2008
Messages
3,175
Likes
601
Location
North of MA
Feedback: 21 / 0 / 0
I recently picked up a DPMS LPK for a S&W AR build.

I assembled the lower and was left with 2 extra springs.

They are both approx 1/8th" thick, one is a 1/4" long, the other maybe a 1/2" long.

Any idea what these are? I did a function check on the lower receiver and everything seems okay. This is my first build though and just wanted to be sure I'm not missing anything critical.
 
If you have not yet attached a stock then one spring is for putting the pin through the back that holds the rear take down pin in place. If you have not installed the front take down pin than one could be from that as well.
 
That photo was incredibly helpful. Wish I saw it before I started...

It's a disconnector and a buffer spring.

Wouldnt there be issues with the trigger pull if I didn't have a disconnector in there already?
 
The buffer retainer is also left over. I have no idea where that even goes. Admittedly I didnt do a thorough search before starting this thread. Is there already a 'build it yourself' thread I should refer to?
 
The buffer retainer is also left over. I have no idea where that even goes. Admittedly I didnt do a thorough search before starting this thread. Is there already a 'build it yourself' thread I should refer to?

That goes in when you install your stock. It is what holds the buffer spring from shooting your buffer and spring across the room. There is a hole in the top of the receiver right next to the loop at the back of the assembly. The spring goes in and then the buffer retainer.
 
The buffer retainer is also left over. I have no idea where that even goes. Admittedly I didnt do a thorough search before starting this thread. Is there already a 'build it yourself' thread I should refer to?

do you have your buffer tube/spring and buffer? they do not come in the LPK, the buffer spring and retaining pin go in the hole at the bottom of that big threaded hole at the back of the lower.
 
the buffer retaining pin can be seen in the 6:00 position, the spring is under it.

While you are wrestling with the takedown pin spring and detent, you are also threading the buffer tube in, to the point you press the buffer retainer down and thread the buffer tube in maybe 2 more turns till it hits the center if the pin, but not enough that it won't let the pin move up and down.
IMG_3252.jpg
 
If you look at the trigger in the bottom right of this picture, you'll see where the disconnector spring goes.

The bad part is you have to pop out both of the hammer pins ( part 23 on the kit parts list/picture) to put that spring in
partssmall.jpg
 
Last edited:
You really, really want to take the trigger group back apart and put the disconnector spring in. It shouldn't take more than a few minutes. The buffer retainer can wait until you have a buffer tube.
 
if your disconnector spring is anything like mine, one end was larger than the other, the larger end goes face down into the trigger and the narrower end fits into the disconnector
 
You will find Kuleck & McKee, "The AR-15 Complete Assembly Guide" immensely helpful for this type of exercise. Available a number of sources, including Brownells and Midway.
 
You really, really want to take the trigger group back apart and put the disconnector spring in. It shouldn't take more than a few minutes. The buffer retainer can wait until you have a buffer tube.

YUP! They call it a Disconnector for a reason. [smile]
 
There are many other videos on youtube also on assembly. Some are bogus some are good. AR15 has been my go to source for info on how to and where to get books dvd tools.

For those that do a few jobs here and there

http://www.wttool.com/product-exec/product_id/8993/nm/13_Piece_Gunsmith_Punch_Set_WT_Import_ This set is what I use for most of my work, along with some longer punches purchased frome wholesaletool.com

Mind you these are for once and a while home DIY.
 
Back
Top Bottom