I got tired of using a water bottle and hose for test firing my guns. Especially when at the hotel rooms at events. So I made a basic little case to enable me to safely fire the cannons indoors. This will work great in the shop and at the hotel room at events. I can also use this at static displays and shows to "Safely" allow people to see the cannons fire...... I made box frames for the sides and ran a 1/4" rabbet in the frame to fit a 1/4" thick sheet of shatterproof acrylic. The top has a large lid to enable me to remove bb's and change out the foam when it has been used up. I made a slot in the top and bottom of the box to allow foam sheeting from 1" to 2" pieces. Behind the foam is a sheet of shower liner that decreases the velocity of the bb's. I got the idea of the shower liner from Jeff L., he uses the liner in his baden. The stuff is light, can be glued to anything, and can be cut to fit... very nice, cheap stuff. You can get it at Home Depot or Lowes. I use a small piece of fitted wood to hold the foam next to the back "slot". The front has a large opening in it to allow for test firing twin, trip, or Quads from the ship... Just place the ship stern into the hole, put on glasses, and fire away... The MK1A2 is the adaption plate for single firing cannons. This is a plate I made to fit the front, covering the opening.. The plate has a hole to fit the barrel into and is slotted to fit different size barrel lengths. Both coil and straight mags will fit. I used two standoffs under the gun, attached to the plate, this holds the velcro straps used to secure the gun while firing. I added a holder for the bottle, firing actuator, and spare speed loaders for the guns... There is also an acrylic window in the plate for viewing from the front... Been using this all day..... I luv the pop, pop, pop with no holes in the walls of the shop... Enjoy!