I'm having an issue with a sticking forward assist on my A2 upper.  It sticks, and at times prevents the bolt from cycling.

I can duplicate the jamming by cycling the gun manually.  Some jiggling of the forward assist clears the issue.

I'm no armorer, but until I can get this upper to one, can I still use the upper with the forward assist missing from its cavity in the upper receiver?

Slipjoint

Yes, but,,,,, You are going to have that big empty hole blowing shit back at you.
Why don't you just rebuild the forward assist? It's not all that hard. Get a TM at the next gunshow for $5 or so.

Hmm, you're right.  My TM doesn't seem to say how to install it into the upper.  It does say how to strip and rebuild it tho'.

Maybe I could put just the FA cover back on ... er, no, it'll just come flying back in my face won't it?

How does the roll pin keep the FA inside its little hole?  It's not in my TM.

Forward assist kits be bought on the market, and are probably your best bet.  They come with all of the necessary parts.  Your problem actually sounds like a weak or broken spring.  How long have you had the rifle?  Was the rifle ever smacked on the forward assist?  The roll pin hold itself in by expanding in the hole.  If you squeeze the pin to put it in, it should expand, if everything goes well.  I agree with Waldo.  A good military TM is a great thing to have for all occasions.  Good luck.    

First, follow this URL to the Old AR15 site whereyou will find a list of links on the left side of the page.  THey will take you to good, somple diagrams of the Forward Assist.  It's not a complicated mechanism so you should be able to put it back together after you take it apart...

[url]http://old.ar15.com/[/url]

Then follw this URL:

[url]http://www.georgiaprecision.com/fsitemap.htm[/url]

to Georgia Precision, where you can buy just the spring and only pay the shipping cost of an envelope...they have what is called a LIGHT ORDER shipping system.

Then go to Sears and pick up a steel Punch set for about $10-$14.
Take teh FA apart, clean it thoroughly with Simple Green and a tooth brush, clean in warm water, and dry thoroughly (I use a small compressor).  Then lightly coat and wipe off some CLP.  Re-assemble with the new spring and forget about it.  Don't ever use it...it should never have been put onto a gun, but that's another entire debate for another thread.