*Nerd hat on* Alright....
The humble boltgun is a good example of looks over fluff. Each "bolt" is a caseless self propellent projectile. Why is there a lot of eject casings flying about hmmmmmmmmmmm!!
I'll answer this one with the FRAG-12, which is (to all intents and purposes) the same design as a bolt from a bolt gun.
A self propelled munition like the FRAG-12 (without casing), Gyrojet, or Bolt does not have killing velocity when it reaches the end of the barrel, or indeed for several feet afterwords. The original Gyrojet munitions could be stopped by holding your finger against the end of the barrel. The initial boost that allows it to having killing potential at close range is provided by a normal charge, like a shotgun cartridge as shown above.
for example the chain sword looks like a mean bit of kit, however its a mechanical device and as such prone to breakdowns, failures and power loss my SPOT/catch is rather than having the weapon as just a chain sword why didnt the designers make the back edge a sword BLADE rather than a metal cover it seems to me it wouldnt have been to difficult to do and should there be a breakage/mechanical failure then you would be left with more than just a club to bludgeon your enemy with
Generally I would assume that the chain is continuous through both the front and back side of the chain blade, with the back end covered to prevent killing yourself when it inevitably bounces off of something (ala Dawn of the Dead). Cutting the chain in half to include a blade on the back would require a secondary motor at the top for the chain to oscillate properly, and still have the same problem as not having that cover on the back (ie. killing yourself when the blade bounces).
My biggest issue is that the chain sword would inevitably foul up quickly when fighting unarmored men because chainsaws tend to get soft moist tissue stuck in their teeth which clogs the mechanical mechanisms (like when cutting down sapplings, or running it through the dirt).
Iv thought of another, i read somewhere that you can recharge a las gun pack by chucking it into a fire? I threw a car battery into a fire when i was a kid. The result was interesting.
Supposedly their built for that (which is why they issue lasguns and not extra-expensive cased munitions to everyone). The chemical* mixture inside is supposed to be able to absorb energy through thermal or solar sources (the later through a tiny solar panel at the top). Though both the uplifting primer, and the 3rd ed codex where it first appeared suggest that it leads to the charger quickly degrading.
*not to be confused with science's definition of "Chemical", but the bad sci-fi definition of "Chemical". IE "God Juice".
Example:
"How are we flying?"
"It's CHEMICAL!"
Yup a normal hand inside, powered by the fibre bundle muscle's. The reason i asked i read Marneus Calgar punched a hole in an Avatar, thought itd be quicker.
It was quicker, and it was in the process of impaling him on a giant flaming sword. Calgar just happened to uppercut it in the middle of the process.
Didnt yarrick get it off of that big ork Ghagskull thraka?
A nob, yeah.
Ghaz is about 19 feet tall ( I kinda wish I was kidding here, 6 meters tall ), which I guess isn't that much when you consider that average orks are about 10 feet (3 meters).
Something that's been bothering me is the bolt in the Bolter, the hunk of metal that's supposed to move around inside the end of the barrel and is the thing that makes the gun you know, work... Now, I'm no gun nut but in my world that should be at least roughly aligned with the barrel...
I always thought it was a rather complicated recharger, for use when the mechanical bolt is stuck.