I was planning to post it for a long time, but finally there it is. My custom bullpup Minimi. I was not sure if the amount of custom work was enough to put it here, so feel free to move it.
It was inspired by the OICW project that I was very interested in. Also, my friend dared me to do it
I based in on a A&K M249 para. It is very sturdy, which is important due to the weight of the build.
Battery: It uses a custom 11000mAH (that big, yes) li-ion battery made from laptop cells. It is located in the boxmag.
Barrel: Madbull 6.03 509mm barrel in a handmade barrel extension.
Internals: M140 spring running on stock gears and motor. I am planning to upgrade that for ROF and durability. The bearings are stock 8mm ball bearings.
Hopup: It had issues from the start, I modified it by making it full metal and fixing leaks. Did wonders.
Other: It has a custom build latch+mosfet circuit with optical piston position sensing to ensure that each cycle is completed even after the trigger is released. It also has active breaking and motor temperature sensing. If anybody is interested I can post a tutorial on that.
Weight: 20 lbs. Actually, the pure weight of the gun forced me to work out and do lots of running. And loose weight. Wonder if it could be used to promote airsoft as a healthy hobby.
The front P90-style wooden grip is attached to an aluminum rail together with an ugly bipod (i bought it as scrap, it is painted very badly, will fix it). They attach to the front of the gun with 5mm bolts and nuts. I need to repaint it due to the beating it takes during games. The cable hanging loose near the mag is the battery and magazine wind-up connection. I used a DIN connector similar to this one http://i00.i.aliimg.com/photo/v0/221572468/Circular_DIN_connector_8PIN.jpg
The trigger uses a switch from some industrial equipment. There is also another thumb - activated switch hidden in the grip, it fires the launcher. The silver connector is used to connect the launcher to the rest of the circuitry.
To be able to aim with the launcher attached I had to make a rail-adaptor-thing. It is based on a tutorial I found somewhere on the net. The ammo is made from empty 5.56 shells with wooden bullets painted gold.
The launcher is made mostly from plastic pipes and fitted on an aluminum rail. Together with the side rails it is bolted to the upper heat shield. To open it I slide the outer barrel a bit forward and lift it up. The cuts are made for easy extraction.
The firing mechanism consists of a solenoid actuator. I ripped it from a machine in a junkyard some time ago. The outer coil pulls the inner metal shaft inside thus firing the grenade, and then a weak return spring resets the pin. Easy and clean.
Lately I installed a better belt loop to carry the beast. I use it often, didn't paint it yet. You can also faintly see the mag winding switch on the grip. I removed the stock due to weight and length issues. It uses a custom shoulder rest made from a steel plate and wrapped in soft foam and soft tennis tape. It is comfy!
All the attachments are controlled from the switches on the trigger guard. From the left they are launcher safety, light, and laser. I also installed a bottle cap for easy filling of the boxmag. The ugly bolt is there to keep the gun together, the original part is somewhere in the forests of eastern Europe.... Must paint it!
Intimidation to the max!
It is quite comfy to use.
I am planning to make it look better, which includes lots of painting, covering cables and such. Up to this date it has witnessed many skirmishes and turned heads of many unsuspecting players. I remember that once during a CQB game (it was running a weaker m110 spring at that time) a member of the opposing team shouted something like "get this f*****g thing away from me" after being pinned down behind a piece of concrete by a wall of fire for a long time.