AR 15 Assembly Blues...

bamacrazy · March 21, 2017, 07:52 PM

I bought a Stag arms lower, DPMS lower kit and an A2 solid stock several years ago. finally got around to assembling the parts. Everything went well until I tried to tighten the Buttstock screw. It was the wrong thread pattern. I was told that I needed an A4 buttstock screw. the threads matched, but when the screw is tightened all the way down there is play between the buttstock and lower receiver. Stock slides forward and back about 1/16 to 1/32". What am I missing? How do I correct this? Any help would be appreciated.

michaeldarnold · March 21, 2017, 08:23 PM

Shorten the screw by carefully cutting it, or shim out the difference with some washers. As long as you get good thread engagement of 5 or more threads, you should be fine, more is better.

Mike

ligonierbill · March 21, 2017, 08:53 PM

Do you have the spacer for the buffer tube? Required for solid buttstock.

FrankenMauser · March 21, 2017, 11:33 PM

As mentioned, you need a spacer for the A2 stock.

If you have the space and it is installed, the next question is:
What type of buffer tube was included in that DPMS lower parts kit (LPK)?

Mobuck · March 22, 2017, 07:42 PM

"Everything went well until I tried to tighten the Buttstock screw. It was the wrong thread pattern. I was told that I needed an A4 buttstock screw. "

I can't remember ever encountering THAT problem.

bamacrazy · March 23, 2017, 05:12 AM

Can anyone point me to a diagram of how or where the spacer attaches?

Mobuck · March 23, 2017, 07:21 AM

"Can anyone point me to a diagram of how or where the spacer attaches?"

OK, lets go back to the buffer tube. The one on your lower is just a plain round tube with a flange at the receiver end that traps the takedown pin detent spring, right? If so, it has a reduced diameter at the rear and a threaded hole in the closed end. The spacer slips over that reduced diameter and is held between the buffer tube and buttstock when the screw is tight.
Hold the lower with the buffer tube pointing up and set the spacer in place, then slide the butstock down over spacer and buffer tube, install and snug up the screw and that's it.

bamacrazy · March 30, 2017, 03:03 PM

Dang, turns out all i neeged was an a2 screw buttstock. Dont k ow what that first one was...

March 21, 2017, 07:52 PM	#1
bamacrazy Junior Member Join Date: January 24, 2015 Posts: 11	AR 15 Assembly Blues... I bought a Stag arms lower, DPMS lower kit and an A2 solid stock several years ago. finally got around to assembling the parts. Everything went well until I tried to tighten the Buttstock screw. It was the wrong thread pattern. I was told that I needed an A4 buttstock screw. the threads matched, but when the screw is tightened all the way down there is play between the buttstock and lower receiver. Stock slides forward and back about 1/16 to 1/32". What am I missing? How do I correct this? Any help would be appreciated.

March 21, 2017, 11:33 PM	#4
FrankenMauser Senior Member Join Date: August 25, 2008 Location: In the valley above the plain Posts: 13,421	As mentioned, you need a spacer for the A2 stock. If you have the space and it is installed, the next question is: What type of buffer tube was included in that DPMS lower parts kit (LPK)? __________________ Don't even try it. It's even worse than the internet would lead you to believe.

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March 21, 2017, 08:23 PM	#2
michaeldarnold Senior Member Join Date: April 8, 2016 Location: St. Louis Suburbs Posts: 137	Shorten the screw by carefully cutting it, or shim out the difference with some washers. As long as you get good thread engagement of 5 or more threads, you should be fine, more is better. Mike

March 21, 2017, 08:53 PM	#3
ligonierbill Senior Member Join Date: May 20, 2007 Posts: 2,448	Do you have the spacer for the buffer tube? Required for solid buttstock.

March 22, 2017, 07:42 PM	#5
Mobuck Junior member Join Date: February 2, 2010 Posts: 6,846	"Everything went well until I tried to tighten the Buttstock screw. It was the wrong thread pattern. I was told that I needed an A4 buttstock screw. " I can't remember ever encountering THAT problem.

March 23, 2017, 05:12 AM	#6
bamacrazy Junior Member Join Date: January 24, 2015 Posts: 11	Can anyone point me to a diagram of how or where the spacer attaches?

March 23, 2017, 07:21 AM	#7
Mobuck Junior member Join Date: February 2, 2010 Posts: 6,846	"Can anyone point me to a diagram of how or where the spacer attaches?" OK, lets go back to the buffer tube. The one on your lower is just a plain round tube with a flange at the receiver end that traps the takedown pin detent spring, right? If so, it has a reduced diameter at the rear and a threaded hole in the closed end. The spacer slips over that reduced diameter and is held between the buffer tube and buttstock when the screw is tight. Hold the lower with the buffer tube pointing up and set the spacer in place, then slide the butstock down over spacer and buffer tube, install and snug up the screw and that's it.

March 30, 2017, 03:03 PM	#8
bamacrazy Junior Member Join Date: January 24, 2015 Posts: 11	Dang, turns out all i neeged was an a2 screw buttstock. Dont k ow what that first one was...