AR15 - Play between upper and lower

[kostarae]

Just purchased an S&W MP15

I was wondering how much play there should be between the upper and lower.

I can see light between the upper and lower when looked at from the side.

Also, i can wobble the upper slightly against the lower.

Is this normal?

Thanks.

 

[45B@cav]

It sounds like the play between your upper and lower is totally normal. If it really bothers you then you can put a accuwedge in it but it's not neccessary.

 

[Thin Black Line]

Accuracy improves when there is less play between upper and lower, but not
enough for most shooters to even notice. The accuwedge will help. Some
other company also makes a replacement rear take down pin that works by
adding pressure through the pin-hole itself. However, this requires some
additional tools/time to take the weapon apart.

 

[kostarae]

I purchased the rifle complete.

I just wanted to be sure this was normal and not a defect I should send the rifle back for.

So its normal to have a little wobble between the upper and lower if manipulated in opposite directions?

Does yours do this?

 

[marktx]

Yes, perfectly normal. It's the nature of the beast.

 

[Tarvis]

It's normal, no worries.

Also, you're supposed to check that sort of stuff before you pay for it .

 

[ProCarryNAustin]

You also might check on these.

http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=339281

I would not recommend them for a combat rifle, but for target work it should tighten up the play.

Daniel
Austin, Texas

 

[RockyMtnTactical]

A little play between the receivers is perfectly fine for function.

 

[Darthbauer]

My RRA has so little play that before I hit 500 rounds she didn't even want to come apart with the pins out. I don't know about S&W though.

 

[Slamfire]

A curious phenoma for the AR15's is that tightness, so critical for accuracy in a bolt rifle, makes absolutely no difference in an AR.

These things can rattle and shoot tight groups.

What is the most critical is the quality of the barrel, and quality of the bullet. Assuming the sights are mechanically tight.

A friend of mine, who was listed as one of the top 200 high power shooters in the Nation, you could rotate his lower an incredible amount around his upper.

What made the difference was his Kreiger barrel, Malazzo trigger, and his skill.

I prefer a tight fit, use accuwedges. But it is a preference, not an accuracy requirement.

 

[trykp]

same with mine. slight play. I see like half a milimeter of light as well passing thru spacing by the rear take down pin. i ended up getting an accuwedge but there was still a slight play by the front pivot. but overall its a bit more solid now.

 

[rcmodel]

I would not recommend a wedge style take-down pin, as if over-tightened, you can crack a lower or upper pin hole.

I really do like the little rubber Accu-Wedge though. It not only takes all the slack out, but makes the gun sound & feel solid, like a bank vualt door.

http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=698479

 

[kostarae]

I took a trip to the gun store.

I handled the MP15 they had there along with the Bushmaster.

That Bushmaster was TIGHT compared to both their MP15 and my MP15.

I can rock my upper back and forth slightly....but that Bushmaster wouldn't budge.

Makes me think the MP15 is of lower quality (rickety)

I will be firing it for first time this week...probably wednesday....but already i am unhappy with the movement in the upper

 

[FMF]

I guess I got lucky. My M&P15 is so tight I used to have use a pick or flat head screw driver to remove the pins. After several disassemblies it's much better but there is still no play between the upper and lower when locked together.

 

[kostarae]

Maybe you got yours while Stag was making them.

Both MP15's I have handled had the same play.

I can move my upper about a centimeter while the lower is stationary. It just seems like it should be more tight than it is.

Anyone else have a loose MP15???

 

[flyboy1788]

my m&p 15a has SN 61,xxx and it is very tight, yet not too tight were i couldnt use my thumbs to push out the pins. On the other hand the two bushmasters I held at the store seemed as if you could almost jam an oreo between the upper and the lower. ok, maybe i exaggerated that a bit but you get the idea. to you guys with the smiths with the loose upper to lower fit, what serial numbers are they?

 

[trykp]

whoa... with your gun fully assembled, both takedown pins in place, you can move you gun a Centimeter?!?!

maybe lets see some pics if something looks odd

 

[cracked butt]

How tight the receivers fit makes no difference-zilch- when it comes to accuracy. If the rifle starts out tight, it will eventually loosen with wear anyway.

 

[flyboy1788]

cracked butt is right. mine is still tight, but it has loosened after use a little bit. i wouldnt worry too much about the wobble

 

[kostarae]

My SN is 80***

Maybe I could upload a video to youtube and get a better opinion from yall

 

[AK103K]

I have a Bushy that was loose as a goose. I dont know if its just a coincidence, but its also been the least accurate AR I've owned.

I tried the Accu Wedge, and it wasnt big enough, so I made one out of a drafting eraser that was, and solved some of the wiggle. I then went to the "O" ring on the front lug fix, and that got things solid. No more wiggle.

Its still my least accurate AR, but at least now, it doesnt bug me as bad.

 

[Coronach]

Accuwedges and anything else small, rubber/plastic and wedged into the innards of the gun are bad ideas if the gun is intended for "serious" use. They can (actually "will", but most guns don't see enough use for the inevitable to happen) come apart, and parts can migrate to places where they can tie up the gun. That's a quick fix if you're plinking, more of a PITA if you're hunting or competing, and could be fatal if you're fighting.

Mike

 

[Howard Roark]

The best way to eliminate play is to either bed the upper and lower or drill up throught the lower and tap into the upper using a screw to tighten them.

 

[JDGray]

Makes me think the MP15 is of lower quality (rickety)

My buddies Colt was the loosest fitting AR that I've seen, no one calls them rickety

But it didn't have a centimeter of slop Maybe a millimeter

 

[Bartkowski]

I can move my upper about a centimeter while the lower is stationary.

Are you sure about this? The thing shouldn't be together if it moves that much.