ThIs gun is finished...but the firing mechanism sucks....I would really appreciate it if someone could build this model, and modify the firing mechanism...I am willing to collaborate. other than that, this gun really looks promising, the grenade design is perfectly designed to fit in the barrel. I will show you how to make each individual piece afteri get them modification, or when I have time. as you can see, this is a really long instructable...but each step goes straight from the last, and the pictures are really clear.
Step 1: The Barrel
you need 4 red connector, 4 yellow connectors, and 8 little green rods.make a square using the connectors, yellow ones facing out of the circle and put two green rods on each yellow as shown.
Step 2: The Barrel Cont'd
You will need 12 of these.just two green connectors attached by a white rod.
Step 3: The Barrel Cont'd
you need 4 long orange roods. attach a orange rod in the center of each yellow connector.then attach the greens as shown,one on top of the next one.
Step 4: The Barrel con't
do the same thing you did with the first four greens, with the last 8, be sure to space them out a little.
Step 5: The Barrel Cont'd
this is one of the parts that needs to be modified,but...where ever theres a green connector hole,place a yellow rod through it with a single grey connector attached to its side...this only applies to the first two rows.
Step 6: The Barrel Cont'd
next...add two single grey connector to each orange rod and put the yellow rod through the holes of the grey connector.
Step 7: The Firing pin...ugh...
this needs lots of modifications...just a simple red rod with a orange connector on the side and end (does not need to be broken)
Step 8: The Firing Mechanism
Also needs modifications, its a simple block trigger.two red rods,and you can use all white snowflakes, i just ran out of them.and an orange connector with a blue rod on it.