Gun function here it is: the gun connects to ports he's built into his left shoulder, it's activated by a pressure trigger, which would rest in his left hand and connected to the gun by a flexible, slightly armoured tube in which the wires (don't know exactly what they'd be) go through and connect to the gun, activating the firing function and rotating the clip (clips are circles, it's built like the Lego version but the clip turns and theirs only one whole to fire from) but there is a safety switch connected to the trigger that has to be flipped off, he built it so he didn't accidentally fire it while wearing it.
It fires smoothed and pointed stones.
The clip is circular and holds the stones in small tubes slightly deeper than the stones length.
Originally the firing function worked by holding stones in pressure, when the trigger was activated it quickly moved a small, piece that held the stone, up, firing the stone with moderate force and distance (like one of the Lego stud shooter guns, don't know how to explain it better but I know how it would work.). Due to the design of the firing function the most the stones could do was annoy and possibly stun, but if it got a lucky hit on a lesser/weaker armoured area or some area without armour and the stone fired straight enough it could pierce with the pointed tip, mainly just causing mild pain but it could blin if it hit an eye.
The aim is not the best and it can backfire and jam which requires taking out the clip and removing the stone.
After coming to the village he traded for some gunpowder (or whatever equivalent they have) and upgraded his gun, making it so that when the trigger was activated it would cause a small spark in the firing tube, igniting a small amount of gun powder behind the stone firing it with greater force and speed (it worked kind of like one of those older pistols only it didn't need cotton and had a bigger clip but it needed to be self reloaded). This one hit with more force and had more of a chance of stunning but it still wasn't relatively lethal, but if it got a lucky hit it would imbed much deeper and cause more pain.
It is more prone to backfires and has a high have of causing a small explosion and some damage, which is typically easily repairable.
Tekan has 5 clips built in total and all of them can be reconfigured to the old function easily for him, still does require some time, but if someone else who didn't know what it was supposed to look like would take longer.
He has enough gunpowder ( or whatever it is) and stones to reload all of the clips once, afterwards he'd have to reconfigure the clips and carve more stones.
If he messes with the clip while its in the cannon he can actually make the cannon into a grenade that will explode with moderate range and launch the stones but it will destroy his cannon so he only considers that a last resource. If he had rope he could also stick the other clips onto it, increasing the explosions force, range and amount of stones.
When it backfires it tends to cause some damage to him but so far any damage he's taken from it is repairable and can be ignored for a bit.
It can be used for distraction/misdirection tactics. Launching a stone farther from where he is redirecting the attention of whatever he's hiding from.
Does this work? If some of it doesn't make sense I'll try to rewrite it, I know what I'm trying to say and how it'd work but I have trouble explaining it.
Also @Timageness does any of this make sense?