I have them in a Bushmaster and a Colt, and they fit perfectly.  I could not close an Oly on one, as the upper and lower fit too tight already.  Did you put it in the right spot?  They go all the way to the rear, with the "point" to the rear also.  You probably had it right, but just checking.  

They'll fit with a bit of sanding using a dremel rotary tool and a disc/drum.  I've not noticed any appreciable increase in accuracy.
They do serve to eliminate annoying rattles in some guns, though.  

i had the same problem with my armalite when i got mine. trim the wedge until it fits. It doesn't do anything for acuracy but makes the upper and lower a nice tight fit. eliminating movement and rattle.

If you really want to "fix" something buy a titanium firing pin.  They don't do anything either, but at least they go in easy, without having to cut them down.  [}:D]

I stand corrected.  Thank you for the edu-ma-cashun.

Great.  This is a good one.

No, our rifles don't come with accuwedges.  We deliberately build them too tight for them, and they don't need them.  The idea of building a rifle loose enough for one of these things, let alone sending one with our rifles, is laughable.  We'd be embarassed.

Here's a neat technical fact:  The looseness between the upper and lower has NO effect on accuracy.  We build our rifles with a close fit for the morale of the shooter, not for any technical reason.  The Army Marksmanship Unit uses a bit of epoxy to tighten their rifles for the same reason.  In fact, being too tight puts stress on the parts that will lead to earlier failure.

When you get into a shooting position in competition, where accuracy counts the most measurably, sling tension and position naturally bias the upper against the lower reciever consistently.  In tactical situations where no target sling or a loose position are both common, this looseness is far less important than other accuracy detractors.  Yes, it was rigorously tested by the Army.

For heavens sake, don't think that ArmaLites failure to accept a so called acu wedge or whatever is a problem with the rifle.  It sure isn't.  It's proof that we build em right in the first place.