The AS47 shotgun and the UHC UZI Mini electric airsoft gun are pretty good ones.
Some good sites are: Airsplat.com, evike.com and airsoftgi.com
see the link below
Echo1 is a very world renowned airsoft company and is very esteemed. They manufacture some of the nicest airsoft guns in the world.
Check some of the bigger airsoft retail sites - most have a boneyard section where you can buy damaged guns for cheap.
Google the following and you will get the results (they are specific stores), they all sell airsoft guns, some are specialty some are not: Canadian Tire Wal-Mart Velocity Arms Capital Airsoft Bass Pro Shops Mach 1 Airsoft 007 Airsoft Buyairsoft
Here are some good websites: airsplat, shortyusa, airsocom, toysarsenal, and mr. airsoft. Those are some good websites if you want to gget quality guns that will last. Most of those sites are American, try www.mach1airsoft.com for Canadian good quality guns.
some do and some dont depends on how its made
Some good airsoft websites are AirRattle, Airsoft Station , Evike , Airsoft Megastore , , Airsoft Atlanta , Airplat , AirsoftGI , ShortyUSA , Renagade Airsoft , Trinity Airsoft , Godfather Airsoft , Airsoft Outlet and Airsoft North West, airsplat.
Some of us love them.
One would be able to find out more information about m4 airsoft guns online on Amazon. Two other sites that have some information about m4 airsoft guns are wikiHow and HobbyTron.
You Can't. Good BB guns cost. You might find some used ones on Craigslist.
Yes some airsoft guns can kill birds