There’s nothing quite like [Elliot]‘s cherubic sense of wonder and maniacal laughter after he tests his fully automatic AA battery-launching air gun. That fires 600 rounds a minute. At 200 feet per second.

We need to take a minute and say [Elliot]‘s gun is stupidly unsafe. He used PVC pipe to hold air pressure, so that may… explode one of these days. Also, the AA batteries coming out of the end of the barrel have the same kinetic energy as a .22 rifle bullet.

The mechanics of the gun is a simple blow forward bolt. When he pulls the trigger, the bolt – and battery – are forced forward due to air pressure. After the bolt has cleared a plug, air is allowed to flow through the bolt pushing the battery along with it. Once the pressure in the barrel is back down to normal, a spring forces the bolt back into place and the 23 round magazine loads another battery. Simple, really. [Elliot] posted some pics of his gun on the spudfiles.com forum.

The gun is accurate to about 100 yards. It’s a very impressive piece of engineering for a bit of PVC pipe, but we don’t feel the need to copy this one. Check out the videos after the break to see this thing in action.

As an amateur radio enthusiast, [Andrew] sometimes has to set up impromptu antennas up to 160 meters in length. The easiest way to get these antennas off the ground is to drape them over trees, a feat normally accomplished by lofting fishing line into the air with a slingshot or bow and arrow. [Andrew] thought slings were so last century, so he came up with a spud gun inspired antenna launcher.

The launcher is built out of PVC and launches a foam filled tennis ball that can reel out 150 yards of Spectra line. In a moment of brilliance, [Andrew] decided to add an augmented reality HUD. The display is actually [Andrew]‘s phone running an app called Geocam that provides him with a display of elevation and azimuth overlaid on the phone’s camera feed. The results of [Andrew]‘s build are fairly impressive. The cannon was able to lob a tennis ball over a 110 foot tree at half the pressure rating of the PVC. The grouping was pretty tight as well, more than sufficient to run a line over a tree.

[Andrew]‘s antenna cannon is an awesome piece of work and unlike most french fry cutters, it’s a useful tool. If you’re interested in seeing 160 meter antennas heaved over the tops of trees, amateur radio field day is next month week, June 25th and 26th.

If you get in the line of fire this golf ball launcher is gonna leave a mark, or worse. It’s based on the same premise as the sausage gun, but now everything is automated and no meat products are used.

A hopper stores a row of golf balls. When it comes time to load, a ball falls into the chamber, starter fuel is sprayed into the combustion area with the aid of a fan, and after both chambers are sealed the propellant is ignited.

We’ve embedded two videos below for your amusement. It looks like [Chrille] and his friends are being careful with their creation. We’re glad for that because this is about as dangerous as the high-velocity ping-pong ball launcher.

While doing serious fruitcake research, (no, really) we stumbled across the Great Fruitcake Toss held every January in Colorado. The particular entry above caught our eye. Omega 380 was built by a group of Boeing engineers and currently holds the distance record of 1,420feet. It’s a large compressed air cannon. All pressure is human generated using an exercise bike turning a pump. Apparently the team’s first contest entry was a classic surgical tubing slingshot. It eventually broke down during a very cold year, so they switched to this newer design. You can see more videos on the Operation Fruitcake blog.

[via pspmod]

The gun is pneumatic, so pressure was supplied from a 7-800psi CO2 paintball gun through this quick disconnect. [Larry] needed an adapter to connect to the 1/4″ regulator input. He made the small chamber, with each connection, and found that it acted as a helpful expansion chamber for the gas supply.

The lower pressure storage chamber is fed about 100psi from the regulator. To release the pressure to the firing chamber, he used this electric water sprinkler solenoid. These take around 12VDC and slightly slow the pressure expansion into the firing chamber

The trigger was built using a simple safety mechanism – two momentary push buttons have to be depressed to fire the sprinkler solenoid.

The get a good seal on the Shmooball, he cut down a beer cozy to act as reusable wadding.

The wadding fits quite well around the 2.75″ Shmooball. The twine keeps the wadding from going the way of the Shmooball.

A velcro mounted laser pointer provides quick aim for chasing tricky speakers.

Thanks to [Larry] for giving us the tour!