Is it normal to have a tiny 'freedom'/movement between upper and lower? (AR15)

All of mine do, some more than others. There's mods and products to buy if you want to eliminate the slop.
 
Yes and the more you tear it down the loose it will become. I have seem a few really old sloppy ARs at my club but these old guys still. Pound the 10and X ring with them. One club member has a A1 that looks like its been in combat for years with out ever getting to the armory. Thing rattles and clangs but I never seen it fail...
 
This worked great for me, as good or better than an accuwedge: Separate your upper and turn over. Push a #7 O-ring to the base of the front pivot lug. Might need to force it between the lug and forend with an old credit card etc. Might be a little tight to replace the pins.

Your local hardware store probably has the O-rings in the plumbing section.
 
goodzilla said:
+1 on the o-ring on the pivot (front) post. Use an o-ring as thin as you can get away with.
Click to expand...

Ditto regarding thin. I had some o-rings in my garage but they were too thick. The #7 is relatively thin and worked. ~69 cents.

There are a few on arfcom who claim an accuwedge or o-ring fix will contribute to faster wear on the post / lug holes but I call BS. IMO a small amount of play on the .458 I just built would more quickly pound itself into a much larger amount of play if the pins were loose. The o-ring is in there very tightly and will absorb some energy. YRMV...
 
Years ago, my son was complaining about movement between the upper and lower. Except for the fact that he was a really good shooter I would have ignored him. I skim coated the lower with epoxy to take up the play, think of it as match fitting or bedding the AR. Worked really well and to make sure that it lasted a long time, we pulled both pins and pulled the upper straight up for maintenance. It still is very tight (although not used much for the last 6 or 7 years). The wedge in mine does almost the same thing. I always went the extra mile for him, weighing out each charge and then loading mine on the Dillon.
Funny thing is he went into the service and called me from boot camp bitching about the rifle he was issued. Said he never saw a rifle so loose and he never could shoot it accurately. A distinguished high master that couldn't shoot expert in the Army, boy was he pissed. It was stamped "Hydra-Matic" . The kid just turned 25 this week so I guess the rifle was a bit older than he was!
 
sbi said:
OK, not quite sure I understand where to use the O-ring.
Click to expand...

This o-ring looks way to thick to me, but it shows the location on the pivot post.

IMG_6260.jpg
 
mac1911 said:
How about bedding the lower with glass bedding or steel bedding?
Click to expand...

Could be done, I suppose, but not worth the work and aggravation. Drill or grind the lower to give the bedding a mechanical bond, enough bedding to touch the lug but not enough to glue the 2 together, very good chance another upper wouldn't fit without grinding out the bedding.

Or, an O-ring, foam earplug or $4 plastic wedge.
 
Machines said:
Are Anderson lowers more prone to this? I have one with a Colt upper and it's pretty darn wobbly. Been using the O-ring trick.
Click to expand...

Maybe, or it could be the combo. Any chance your Colt upper could be mid 90's or earlier? Those had larger front pivot pins. Honestly, the most loose AR I ever had was a factory Colt Match HBAR, pre ban. Sold it to a rude LGS because my brother's SKS was a better shooter and pre ban Colts were hot at the time.

My Anderson lowers have a nice close fit to Anderson uppers and a couple Spikes uppers that I have tried. Best fit I have seen is on a Windham factory rifle upper and lower. I'm sure there are other good ones, that's just what I know.
 
Machines said:
Are Anderson lowers more prone to this? I have one with a Colt upper and it's pretty darn wobbly. Been using the O-ring trick.
Click to expand...

I have 2 Anderson lowers. They both fit nice and snug on my RRA uppers a tad loose on my Tactical Solutions AR22 upper, average fit on my areo precision upper receiver. I have a older armalite A2 NM upper receiver I have not tried yet. One Anderson will be matched up with the armalite to build my NM 22lr upper.

I'm curious if there is a actual spec they follow when they go through overhaul at the US depot armory?
 
KMM696 said:
Could be done, I suppose, but not worth the work and aggravation. Drill or grind the lower to give the bedding a mechanical bond, enough bedding to touch the lug but not enough to glue the 2 together, very good chance another upper wouldn't fit without grinding out the bedding.

Or, an O-ring, foam earplug or $4 plastic wedge.
Click to expand...

Well for a nice snug "matched" fit it would be a good option. I,don't know to many people with accurate ARs that bedding would increase that accuracy more by bedding.

My best fitting upper lower is my factory new RRA NM you can't push the pins out with out using assistance from a brass punch. Zero wobble.
 

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