AR15.Com Archives
 How to remove play between upper and lower
Mioduz  [Member]
5/6/2009 5:36:04 PM
I just assembled a new rifle, but I am geeting a bit of play between the upper and lower. I'm sure that it will not affect performance, but I like everything to be as perfect as possible. Any suggestions??
87GN  [Team Member]
5/6/2009 6:17:57 PM
No affect on performance whatsoever, and easier to disassemble.

You can use the Accu-Wedge, but those are a PITA in my opinion.
mtforlife  [Team Member]
5/6/2009 6:48:15 PM
Originally Posted By 87GN:
No affect on performance whatsoever, and easier to disassemble.

You can use the Accu-Wedge, but those are a PITA in my opinion.


yep thats pretty much the truth
scottrh2  [Team Member]
5/6/2009 9:01:59 PM
Originally Posted By Mioduz:
I just assembled a new rifle, but I am geeting a bit of play between the upper and lower. I'm sure that it will not affect performance, but I like everything to be as perfect as possible. Any suggestions??


Live with what you have or sell it............it will never be perfect.
_DR  [Member]
5/6/2009 9:08:21 PM

O-ring on the front takedown lug if it bugs you - but there is supposed to be play - it's normal.
docmcb  [Team Member]
5/6/2009 11:24:21 PM
+1
Originally Posted By _DR:

O-ring on the front takedown lug if it bugs you - but there is supposed to be play - it's normal.
Go to Home Depot, in the aisle with the small plumbing faucet repair parts, find an O-ring with a 1/2" diameter hole in the center and a 3/32" thickness. They will probably be in a pack of 10 for less than $2. Remove the upper receiver, slip one O-ring over the front lug and reassemble.

Russ4777  [Team Member]
5/7/2009 12:02:20 AM
Do this. If the o-ring shears, then get one that is slightly smaller in cross-sectional diameter.

Tekpc007  [Team Member]
5/7/2009 9:12:32 AM
accu wedge did the trick for me , was no hassle and stays in place.
liaisons  [Team Member]
5/7/2009 9:33:00 AM
Originally Posted By 87GN:
No affect on performance whatsoever, and easier to disassemble.

You can use the Accu-Wedge, but those are a PITA in my opinion.


Exactly what he said...
45FMJoe  [Team Member]
5/7/2009 10:06:36 AM
Originally Posted By Tekpc007:
accu wedge did the trick for me , was no hassle and stays in place.


When you start having cycling problems, that is your culprit.
chevyrulz  [Team Member]
5/7/2009 10:57:29 AM
for a more permanent fix:

carefull apply the epoxy to the left and/or right side of the forward lug hole (pivot pin lug) on the upper receiver to correct side to side play between the upper/lower receivers. this coupled with a solid stock like a magpul CTR will make the rifle feel much more solid. a little play between receivers is completely normal.

using a toothpick or small brush apply a little epoxy to one side, make sure it's evenly dispersed, and let it cure. don't get any inside the hole where the pivot pin goes through. apply only on the flat surface surrounding the hole.. once cured sand it flat if necessary & test fit. repeat until desired tension is acheived.
SSN_Doc  [Team Member]
5/7/2009 5:15:33 PM
Originally Posted By chevyrulz:
for a more permanent fix:

carefull apply the epoxy to the left and/or right side of the forward lug hole (pivot pin lug) on the upper receiver to correct side to side play between the upper/lower receivers. this coupled with a solid stock like a magpul CTR will make the rifle feel much more solid. a little play between receivers is completely normal.

using a toothpick or small brush apply a little epoxy to one side, make sure it's evenly dispersed, and let it cure. don't get any inside the hole where the pivot pin goes through. apply only on the flat surface surrounding the hole.. once cured sand it flat if necessary & test fit. repeat until desired tension is acheived.



Or I did it this way. It can be done to look prettier, but I did it in a short ammount of time and not too many folks look inside my receiver anyway.

I decided to try it on my Service Rifle (Match rifle). This isn't the horrific procedure that will weld your rifle closed, as long as you use some common sense. I'm not sure if it will improve accuracy but I decided to document my work so you can see what you think, and take it for what it's worth. I just wanted the slop out to make me feel better.

Here's how I did it:

1. First I got my supplies together:
-Cotton tipped applicators for cleaning, applying wax, and mixing and applying the bedding compound
-Bedding compound (I used JB Kwik, because it begins to set up in 4 minutes, and is cured in 4 hours. This makes it easy to control, and easy to go back and build up if you need to before full cure)
-Johnsons Paste Wax as a realease agent
-Acetone for degreasing the bedding area of the receiver.
-Disposable plate to mix the bedding compound on.



2. Degrease the interior of the lower receiver with CTA (cotton tipped aplicator)and acetone:



3. Wax the rear lug, be sure to apply liberaly and get some in the holes. (sorry for the crappy pic.) I also applied it to the retaining pin as well.:



4. Measure out equal portions of epoxy and hardner, and mix well: (I only had about a third of the total needed for the job in this picture.)



5. As it just barely starts to firm up, start to apply some bedding compound to the interior of the receiver (this makes it easier to control where it goes, but leaves it runny enough to fill the edges of the receiver shelf.)



6. I made a layer that was below the pin holes and only came just forward of the pin holes. Let this sit until it firms up to about the consistency of Playdough. Shut the receiver and push in the pin. Open the receiver and see where your at. JB Kwik should form a bit of a shelf for the bottom of the rear lug.



The bearing surface wasn't as big as I was wanting, so I mixed some more an applied it in front of the previously built shelf and brought it back over the existing shelf. I waited until I got to playdough consistency again and shut the reciever to get a shape. I fiddled with it a bit more with the wooden handle of the CTA to move more back and make a more squared up leading edge. I shut the receiver again an put the pin in. It was tight but still doable by hand. This is whereI wanted it. I resisted the urge to rock the receive back and forth and wallow out the nice platform I made.

Here is the final product ( I did clean up the small stay bit of bedding on the upper lip of the receiver and the extension threads). Not pretty but firm, and functional. No movement in the receiver. If this is what the OP wants to do. This is teh way I did it without welding the gun shut, or creatiing a solid fire control group, or some similar tragedy. Will it improve accuracy? I don't know, but It can't hurt, and it feels nice. All the bedding is below the pin holes, so the pins never really became an issue, but I'd still wax them just in case.




Russ4777  [Team Member]
5/7/2009 9:16:11 PM
Originally Posted By SSN_Doc:
Originally Posted By chevyrulz:
for a more permanent fix:

carefull apply the epoxy to the left and/or right side of the forward lug hole (pivot pin lug) on the upper receiver to correct side to side play between the upper/lower receivers. this coupled with a solid stock like a magpul CTR will make the rifle feel much more solid. a little play between receivers is completely normal.

using a toothpick or small brush apply a little epoxy to one side, make sure it's evenly dispersed, and let it cure. don't get any inside the hole where the pivot pin goes through. apply only on the flat surface surrounding the hole.. once cured sand it flat if necessary & test fit. repeat until desired tension is acheived.



Or I did it this way. It can be done to look prettier, but I did it in a short ammount of time and not too many folks look inside my receiver anyway.

I decided to try it on my Service Rifle (Match rifle). This isn't the horrific procedure that will weld your rifle closed, as long as you use some common sense. I'm not sure if it will improve accuracy but I decided to document my work so you can see what you think, and take it for what it's worth. I just wanted the slop out to make me feel better.

Here's how I did it:

1. First I got my supplies together:
-Cotton tipped applicators for cleaning, applying wax, and mixing and applying the bedding compound
-Bedding compound (I used JB Kwik, because it begins to set up in 4 minutes, and is cured in 4 hours. This makes it easy to control, and easy to go back and build up if you need to before full cure)
-Johnsons Paste Wax as a realease agent
-Acetone for degreasing the bedding area of the receiver.
-Disposable plate to mix the bedding compound on.

http://i39.tinypic.com/qzr61l.jpg

2. Degrease the interior of the lower receiver with CTA (cotton tipped aplicator)and acetone:

http://i44.tinypic.com/20z4i7c.jpg

3. Wax the rear lug, be sure to apply liberaly and get some in the holes. (sorry for the crappy pic.) I also applied it to the retaining pin as well.:

http://i42.tinypic.com/fvbgpi.jpg

4. Measure out equal portions of epoxy and hardner, and mix well: (I only had about a third of the total needed for the job in this picture.)

http://i44.tinypic.com/b8jo13.jpg

5. As it just barely starts to firm up, start to apply some bedding compound to the interior of the receiver (this makes it easier to control where it goes, but leaves it runny enough to fill the edges of the receiver shelf.)

http://i40.tinypic.com/qyahyd.jpg

6. I made a layer that was below the pin holes and only came just forward of the pin holes. Let this sit until it firms up to about the consistency of Playdough. Shut the receiver and push in the pin. Open the receiver and see where your at. JB Kwik should form a bit of a shelf for the bottom of the rear lug.

http://i41.tinypic.com/2ihmp04.jpg

The bearing surface wasn't as big as I was wanting, so I mixed some more an applied it in front of the previously built shelf and brought it back over the existing shelf. I waited until I got to playdough consistency again and shut the reciever to get a shape. I fiddled with it a bit more with the wooden handle of the CTA to move more back and make a more squared up leading edge. I shut the receiver again an put the pin in. It was tight but still doable by hand. This is whereI wanted it. I resisted the urge to rock the receive back and forth and wallow out the nice platform I made.

Here is the final product ( I did clean up the small stay bit of bedding on the upper lip of the receiver and the extension threads). Not pretty but firm, and functional. No movement in the receiver. If this is what the OP wants to do. This is teh way I did it without welding the gun shut, or creatiing a solid fire control group, or some similar tragedy. Will it improve accuracy? I don't know, but It can't hurt, and it feels nice. All the bedding is below the pin holes, so the pins never really became an issue, but I'd still wax them just in case.

http://i42.tinypic.com/20psi9k.jpg




Now that is ugly as shit!! In fact it actually looks like shit.
fadedsun  [Team Member]
5/7/2009 9:27:20 PM
My issued m16a2, which is old as heck, shakes and rattles but fires EVERY time.

Plenty of play, and you can see daylight through it. But would I take it to war? YES, my good sir, I most certainly would.

pmurphy  [Member]
5/7/2009 9:39:13 PM
Try the JP Pin. http://www.jprifles.com/1.5.1.7_small_tp.php Pulls the upper and lower together. The other methods force them apart. I'm putting them in all my rifles. The downside is that you need an allen wrench to take the rifle apart.

Phil
mtforlife  [Team Member]
5/8/2009 12:04:17 AM
Originally Posted By SSN_Doc:

ALL THAT




I'd rather live with the rattle than do that to one of my rifles.
nicholsmf  [Team Member]
5/8/2009 4:12:24 AM
Originally Posted By scottrh2:
Originally Posted By Mioduz:
I just assembled a new rifle, but I am geeting a bit of play between the upper and lower. I'm sure that it will not affect performance, but I like everything to be as perfect as possible. Any suggestions??


Live with what you have or sell it............it will never be perfect.


this
USMC-Helo  [Member]
5/8/2009 8:02:18 AM
Originally Posted By pmurphy:
Try the JP Pin. Pulls the upper and lower together.

BUT, that requires tools to field strip and clean. It looks like it would work nicely, but NOT for me, I like the concept of pop the pin and breakdown shotgun style any time in the field or back home.
SSN_Doc  [Team Member]
5/8/2009 8:38:47 AM
Originally Posted By Russ4777:
Originally Posted By SSN_Doc:
[quote]Originally Posted By chevyrulz:

Blah, blah, blah....




Now that is ugly as shit!! In fact it actually looks like shit.


And you only see it, when? It did clean up a bit nicer after I applied it and got it formed to the rear lug. I was just illustrating an option that truly takes all the play out of the upper and lower. Front to back and side to side. The Epoxy can be removed later, and you wouldn't need to use JB Kwick or another brown substance but I like the set time on it and the ability to work it as it starts to harden instead of running all over the place for an hour or so. This method also holds up better than skim bedding techniques where epoxy is applied in very thin layers and is prone to cracking chipping, and faking off.

It's a match rifle. It fits tight, and feels solid. Sometimes feel is important to folks.
It's not for everyone, or for every application, just another tool in the box.
FineUpstanding  [Team Member]
5/8/2009 10:42:06 AM
Originally Posted By Russ4777:
Do this. If the o-ring shears, then get one that is slightly smaller in cross-sectional diameter.

http://www.hunt101.com/data/500/medium/IMG_6260.jpg


Thanks for the pic...makes it easier to decipher. I've heard of the o-ring mod, but seeing it makes it idiot-proof.
robplumm  [Member]
5/8/2009 3:34:39 PM
Everyone wants everything mil-spec...but a little play between upper/lower and the whiners come out. Never handled a an M-4 without quite a bit of play. Only ones that didn't...Accu-wedge. For the truly anal.

Mil-spec = play.
pmurphy  [Member]
5/8/2009 6:10:43 PM
Sorry for my JP pin suggestion. I got mine today and tried to install them. They are hard to install and don't work. Total crap. I'm sending them back to Brownells.

Phil
beemerman  [Member]
5/9/2009 4:15:43 PM
I was wondering about this to. My RRAs rifles are tight as a crabs ass. My Bravos are loose.
Mioduz  [Member]
5/9/2009 5:21:13 PM
Originally Posted By beemerman:
I was wondering about this to. My RRAs rifles are tight as a crabs ass. My Bravos are loose.


dont mess with the RRA, mine was tootight at first, making it nearly impossible to disasemble but after the first 1,000 rounds it starts to loosen up....now it is perfect no play and disasembles easily
BadLuther  [Team Member]
5/14/2009 7:23:39 AM
Nice work Doc! I may have to try it out on my Sig 556 that has severe play between the lower/upper. Thanks for posting your mod.
hmbone  [Member]
5/14/2009 12:17:33 PM
O-ring in the front and if there is still slack then put a foam earplug in the back! You will have a tight gun for about 1.50$
yolop  [Member]
5/14/2009 12:33:42 PM
I have an accu wedge on my DPMS that I'm building. Had it not been GIVEN to me I would have never looked into it. Once the rubber breaks in and the rifle gets shot I'm pretty sure it won't do much but at that point I won't care.

If it has to be perfect spend the money. Buy a Noveske or LaRue or LMT complete rifle. My Noveske has no play in it.
Patrick03  [Member]
5/16/2009 8:19:42 PM
Originally Posted By SSN_Doc:
Or I did it this way. It can be done to look prettier, but I did it in a short ammount of time and not too many folks look inside my receiver anyway.

I decided to try it on my Service Rifle (Match rifle). This isn't the horrific procedure that will weld your rifle closed, as long as you use some common sense. I'm not sure if it will improve accuracy but I decided to document my work so you can see what you think, and take it for what it's worth. I just wanted the slop out to make me feel better.

Here's how I did it:

1. First I got my supplies together:
-Cotton tipped applicators for cleaning, applying wax, and mixing and applying the bedding compound
-Bedding compound (I used JB Kwik, because it begins to set up in 4 minutes, and is cured in 4 hours. This makes it easy to control, and easy to go back and build up if you need to before full cure)
-Johnsons Paste Wax as a realease agent
-Acetone for degreasing the bedding area of the receiver.
-Disposable plate to mix the bedding compound on.


Excellent write-up! Thanks!

I'll give the o-ring idea a try first, and if that doesn't do what I'm looking for, I'll try your JB Weld fix.

Not sure why all the haters on your solution. Who cares what it looks like!
SSN_Doc  [Team Member]
5/16/2009 8:39:44 PM
Originally Posted By Patrick03:
Originally Posted By SSN_Doc:
Or I did it this way. It can be done to look prettier, but I did it in a short ammount of time and not too many folks look inside my receiver anyway.

I decided to try it on my Service Rifle (Match rifle). This isn't the horrific procedure that will weld your rifle closed, as long as you use some common sense. I'm not sure if it will improve accuracy but I decided to document my work so you can see what you think, and take it for what it's worth. I just wanted the slop out to make me feel better.

Here's how I did it:

1. First I got my supplies together:
-Cotton tipped applicators for cleaning, applying wax, and mixing and applying the bedding compound
-Bedding compound (I used JB Kwik, because it begins to set up in 4 minutes, and is cured in 4 hours. This makes it easy to control, and easy to go back and build up if you need to before full cure)
-Johnsons Paste Wax as a realease agent
-Acetone for degreasing the bedding area of the receiver.
-Disposable plate to mix the bedding compound on.


Excellent write-up! Thanks!

I'll give the o-ring idea a try first, and if that doesn't do what I'm looking for, I'll try your JB Weld fix.

Not sure why all the haters on your solution. Who cares what it looks like!


Don't know. A lot of ARF.com folk don't like brass marks on their brass deflectors either.