Thrasher, OK here is the part you need. I just found it in one of my catalogs.
www.deltaforce.com
AR15/M16 Bipod adapter
Item number YH638
It's 29.95 plus shipping.
I agree with knifemaker. Ammoman has some great deals.
I get alot of my 223 stuff from
www.sportsmansguide.com
I'm totally addicted to that catalog. They have just about everything that an outdoorsman would want.
Anyhow they have cases of .223 ss109 rounds for about $150 as case (1000) rounds. I'm not sure about california's laws, but possession of those might get you ass @ucked in the local slammer. However, they are a great round with excellent down range terminal, well, performance shall we say.
Another choice is "WOLF" ammo. Real cheap about $90/1000 rounds. However there are two trains of thought with wolf ammo. Use them alot or no way in hell.
One viewpoint deals with the laquer coating and the steel case. Some have reported that their ejector was affected by the steel to steel contact. This usually results in eventual failure of the weapon.
Some have reported that the laquer case coating builds up in the chamber, which leads to failure. Some say this in not as much of a problem if the chamber remains fairley cool. However, after long strings of fire the chamber gets very hot and when you pause shooting the laquer from the chambered round melts and coats the chamber. Round after round this coating could build up and change the dimensions of the chamber, which is a very bad thing.
The other viewpoint is using them is fine and no big deal, I agree. The point of owning a weapon is to become proficient with it. Well if someone seldom shoots because of the price of ammo, it's kind of pointless in my opinion. It's kind of like buying a busa and not riding it. Kind of hard to get good a something if you never do it, right.
Well I like to shoot. I have been using wolf ammo since they started imports in the 90's. It's a good round IMHO. Do I have any failures? NO. However, I also am a nut keeping my "toys" in proper working order and clean. A clean weapon is a happy weapon. So laquer build up doesn't seem to be an issue for me.
As far as ejector failure, well I could see that possibility happening. I'm have not had one wear out yet but it is theoretically possible. If someone does wear out an ejector they would have spent about $1000 on 10,000 rounds of ammo. Which means they would have saved probably $1000 from not buying the "name brand" stuff. An ejector for the AR-15 costs about $15. Well worth it in my opinion.
Sorry but I'm into firearms. In fact riding motorcycles could be considered a "second" hobby for me, god forbid.
Have fun, Chris