Just bought a low time Bushy A2 and the receiver (upper and lower) has a faded, whiteish, bleached out look to it.  Not the usual dark appearance.  I'm wondering if the previous owner used some harsh cleaning solution on it.  I tried rubbing a little WD40 on it, looked OK for 10 minutes then returned to the faded look.  The buttstock also looks faded.  I tried Armorall on it, seemed to help a bit.  OK to recoat or is there something better to use?  The receiver bothers me more than the buttstock.  Would appreciate your ideas.

I know if you use gun scrubber on an AR it leaves a white film to it . I learned this at work after I was helping the armorer at work , he handed me a can of gun scrubber and then had to go do something else . I didn't know what to do after I sprayed it on and it turned white , I finally wiped it down with oil before he got back and it looked like it was supposed to . Don't know if thats what you have but try something heavier than WD40 and maybe it will fix your problem .

Refinish it.....
ar15.com/forums/topic.html?b=3&f=7&t=194418&page=1

you can use Norrell's moly resin..
the finish is nearly mil spec.
colors comes in Colt Grey , curr mil spec black and ODgreen...

PUT CLP ON IT !!!!!!!  Bushmasters normally DO look the way that you described when the oil has been removed.  My bet is that the finish is okay, it just has all the oil removed.  Put on some CLP, or any oil (even motor oil if that is all you have) on it.  The deep dark black luster should return immediately after apply the oil.

The WD40 is too volitale (evaportes very quickly.  This is why the luster did not last very long when you applied wd40.

I put CLP on the metal and several coats of Armorall on the buttstock.  Looks like that did the trick.  Rifle looks like it should now.  The link on refinishing is really interesting.  I'm going to print it for future reference.  Thanks guys.