So I've scoured the 'net and found all sorts of differing opinions.  Some say they fit between the upper and lower should be snug, the pics should require some force to insert and remove.  They claim the tighter the better for accuracy and reliability.  Other say it can be sloppy, daylight visible between the two, pins you can push out with little or no force and it has no affect on accuracy because the upper is what matters.

 

So what says our group?  Seems to me you don't want too much play/rattle.  But wouldn't want it overly snug either.

it has no affect on accuracy because the upper is what matters

Use an AccuWedge or use a rubber o-ring if the wobble bothers you that much. Be careful though. Some people put up with the wobble in fear if these additional parts breaking and entering the FCG or BCG and causing other malfunctions.

mine is on the loose side and i can hold a 4 inch group at 100 yards. if it fits together and runs then you should be good to go. if you're building a match rifle then the fit might want to be on the tighter side tho. just to take variables out of it.

Usually you will find more play between the upper & lower on either

lower end factory rifles or built rifles where a different upper & lower

mfg. is used.

All the parts are to Mil Spec, but Mill Spec allows for a certain amount 

of tolerance, and one part can fall to the lower tolerance, and the other

to the upper tolerance and then you may have some play.

 

As Lalo suggested, use an Accu-wedge to  take up the small bit of play

and you should be good to go............

An Accu-Wedge will only work on low shelf lowers.  You will not be able to stuff a wedge in a high shelf lower. 

I have not seen any proven documentation that a "loose" lower makes a less accurate rifle.

It doesn't matter, my competition rifle is a 1moa rifle with very loose upper to lower fit, because all the accuracy is in the upper.

 

If it really bothers you, get one of those rear take down pins that tighten up the fit.

 

Like this one for example: http://www.midwayusa.com/product/339281/jp-enterprises-rear-tensioning-takedown-pin-ar-15-stainless-steel

It don't matter

Edited January 26, 201412 yr by High Exposure

I don't matter

You are being to harsh on yourself

fingers are frozen and brain is drunk from the NY/NJ game.

Ive learned to ignore it and havent noticed any loss in accuracy.. The one thing I did try, as Lalo said is the o-ring on the front pin hole (on the lower)..that will tighten it up quite well

It doesn't matter, my competition rifle is a 1moa rifle with very loose upper to lower fit, because all the accuracy is in the upper.

 

If it really bothers you, get one of those rear take down pins that tighten up the fit.

 

Like this one for example: http://www.midwayusa.com/product/339281/jp-enterprises-rear-tensioning-takedown-pin-ar-15-stainless-steel

 

 

I've seen the wedges but never saw that pin before.  Thats pretty sweet.  I think I'll leave it alone for  now until I can get out and put some good groups down at distance.  If I don't like em I'll blame the play and go from there.  Thanks guys

An Accu-Wedge will only work on low shelf lowers. You will not be able to stuff a wedge in a high shelf lower.

You can trim the rubber wedges with a razor blade. I shaved one off and am using it on my M&P "high shelf" lower.