Gear Rifles - design assistance requested

[Varyon]

This is an idea I had (or, rather, shamelessly stole from this thread), for a "rifle" that stored its motive power in a clockwork battery. A good option for how it turns energy stored in said battery into propelling a bullet into some monster's skull, however, has always eluded me.

Until now.

Thanks to the Forgotten Weapons interview with the cofounder of ArcLabs about their GR-1 Anvil Gauss Rifle, I realized I could use a mechanism that pulled the bullet, rather than pushing it, down the barrel. This is what I've come up with. I'll note this is meant for DF, so strict realism is not necessary, although some nods to it would be welcome.

Aesthetically, the weapon would look more-or-less like a typical TL 4-5 musket/rifle, but with an ovoid barrel rather than a circular one (or a rectangle rather than a square, or an elongated hexagon rather than a regular hexagon). Internally, there is a winged "cup" at the back of the barrel, with a hole in top (matching up with one in the barrel; the latter would have a movable cover) for putting the bullet in. Threaded through the wings is a chain on each side, which wraps around and links to itself (going through the elongated portion of the barrel). When the weapon is fired, gears spin to move this chain, in turn accelerating the cup (and bullet within). When the cup reaches the end of the barrel, it strikes a brake (probably made of soft leather, or cork wood), which has a hole in the center for the bullet to pass through - this stops the cup (which slips from the chain on impact, so that the gears can continue turning for a bit rather than coming to a jarring stop; basically, the chain fits it snugly enough that it can be accelerated fairly quickly, but not enough to hold on at the sudden stop at the end). To reload, you flip a safety switch to disengage the gears from the battery, pull the cup back into loading position (it has a tab on it that comes up through a slit in the top of the barrel, and serves as rear sights; for long barrels, it typically has a lanyard attached so you can just grab and yank that back), drop a bullet in, then attach a hand crank, wind the mechanism, detach the hand crank, and finally flip the safety switch back to shooting position while shouldering the weapon.

However, that requires a sufficiently-long reload process that it may reduce the weapons to "one shot per battle," which is very much not what I want. Absent Fast-Draw, and ignoring the time to actually wind the mechanism, I'm thinking you could flip the safety and pull the cup back into position as a single Ready; draw a bullet from your pouch as a Ready; remove the cover, drop the ball into the cup, and replace the cover as a Ready; draw the handcrank as a Ready; attached the handcrank as a Ready; detach the handcrank as a Ready; stow the handcrank as a Ready (you could skip this step if you have it on a lanyard, simply dropping it as a free action); and take a final Ready to, well, Ready the weapon and flip the safety. That's 8 seconds!

What options would I have to speed this up? Having the crank permanently attached would cut time in half, but absolutely ruins the aesthetics of the weapon, so I'd rather avoid that. Might it be feasible to have a folding crank, such that the weapon doesn't have a big bulky thing off to the side normally, but you can pop it out, crank it, and put it back in (with the crank's position serving as the saftey - pulling it out switches the battery to be connected to the winding mechanism, putting it back in switches the battery to be connected to the gears). Or should I allow the battery to store multiple shots, so that reloading during combat only consists of pulling the cup back into position and dropping a bullet in?

For cranking and damage, my inclination is to define battery capacity in terms of pounds, have a character charge it by BL lb with each Ready (either 1.5xBL or 2xBL with an All Out Ready), and have the damage be equal to thr at the ST for which the battery's capacity matches its BL. That is, a battery that can store 80 lb would take a character with ST 10 around four seconds to charge (three or two seconds if going All Out) and deal damage equal to thr at ST 20 (2d-1). Does that sound feasible? Note if you dislike setting battery capacity in terms of pounds, you could instead use Joules - for 5xBL Joules, 7xBL Joules, and 10xBL Joules, respectively (of course, damage probably is unlikely to match up at all using Doug's spreadsheet, but that's fine - this is for Dungeon Fantasy, not Tactical Shooting).

I could go on, but ultimately, these are my current questions (repeating some from above):

1. What are some good options to speed up the loading process? Does a built-in crank make sense? Should storing multiple shots worth of energy be an option, or would we be stepping on the toes of archers too much?
2. Does my BL/cranking time to damage relationship make sense, from a game balance perspective?
3. What sort of weight should these weapons have? I'm thinking of taking the simplified formulae for firearms I worked out based on Classic Vehicles and simply applying a multiplier - that is, a gear rifle would weigh something like 1.2x as much as a comparable firearm.
4. What effect should barrel length have? I'm thinking a longer barrel means the battery can discharge over a longer period of time, increasing efficiency. But by how much - and what should be the "zero point?" Perhaps a "typical" gear rifle is BL 80 and has a 1-yard-long barrel, and weaker weapons can get away with a shorter barrel and still have maximum efficiency, while stronger weapons need a longer one.
5. What about rifling? I like the idea of actual rifled weapons having their brake located partway down the barrel, with a portion of it that only the bullet travels through being rifled, imparting spin (thus, you're basically sacrificing damage to get higher accuracy). Problem is, I want bullets that are made of fired clay (including hollow ones that you can fill with stuff like alchemist's fire) in addition to the typical lead ones, but I don't think said clay would engage with the rifling the same way lead would. Do clay bullets require a smoothbore weapon - or might a wax "jacket" be an option?
6. Caliber. Should the above be for pi, pi+, pi++... or even pi-? How should things scale with other calibers of bullet? One idea might be that the reduced efficiency of having the battery discharge rapidly has to do with the speed of the gears more than the time period over which the energy is discharged, so heavier bullets can get away with shorter barrels to reach maximum efficiency. Even so, what about damage? Should I just scale this like Innate Attack does - that is, if the base is pi, then pi- would be +67% damage (around +2 per die), pi+ would be -17% damage (around -0.5 per die), and pi++ would be -37% damage (around -1.5 per die)?

Any assistance would be greatly appreciated. Hopefully this time I've avoided my chronic issue of "information overload in the first post."