There are now several options available for someone looking for an automatic BB gun. The first two are made by a Russian company Drozd. There guns are a little more expensive than others but very well built.
This one is pretty cool it can shoot single shot 3 and 6 round bursts. It’s manual says it shoots at about 541fps. The downside to this gun is that it only has a 30 round magazine so you have to shake it to reload quite a bit. It shoots regular .177 Steel BBs. There is also a selector switch to switch between 300, 450, or 600 rounds per minute.
Drozd Blackbird - Retail $299
If the original Drozd Full auto BB gun got you excited this one will finish you. It has the same great features as the original Drozd. Metal and High Density Plastics. Semi auto, 3 round burst, or 6 round burst. The major upgrades are that this bb gun has a magazine that is reported to hold over 800 bbs fully loaded. It comes with a stock and uses a larger co2 bottle.
Ok, well this is where it gets really cool. The modding scene for these two Drozd guns is awesome with people making mod chips for them that covert these already amazing airguns to full auto BB guns capable of firing up to 1200 rounds per minute.
They can also both be equipped with HPA or CO2 tanks made for paintball guns for hours of fun at a much cheaper price.
If you want full auto though the drozd blackbird is currently the way to go since it has a huge magazine that has been reported to fit over 800 BBs. Even though the manufacturers specs only say 200.
Another mod will allow the blackbird to fire BBs at over 900 feet per second.