While I personally have no big problems with it, we know that guns are best avoided in official Magic. That doesn't mean there is no place for them in the game, there is some precedent and some guns might be in Unstable, but if the purpose of the contest is to make realistically printable cards, I feel there might be some problems with this card. If the purpose is to make un-cards or cards for custom sets, it could be fine. Except for this, I have no problems with the name in a vacuum or with the absence of flavor text (no room for it).
To be clear on where this design came from, it was designed as a card in my Piracy set, and was intended to be more historically representative of a pistol/gun that could only shoot a few times without being reloaded. I do understand that Wizards has tended to avoid guns in their cards, however, it strikes me that in the right context of a set, anything like drinking (e.g. Sleeping Potion), sex (e.g. Alluring Siren), etc. can all be done. Additionally, I am not clear on what is distinct between a gun and a sword and a gun or a cannon - both of which were featured in Ixalan. I definitely understand guns have a squeamishness about them, especially in light of recent tragic events in the US, and I am one of the biggest gun control people out there, but I also am concerned that this deduction of 1.5 points was a pretty dramatic hit. It seems to me that given that Magic is a 13+ game, and that as long as the card isn't using guns in a grievous way, I don't really see an issue between it and something like Pirate's Cutlass. I only ask for a distinction to be made here that isn't rooted in "guns are bad."
"Whenever you equip" is not standard template. Auras and Equipment "become attached" to creatures, so this should be "Whenever Flintlock Pistol becomes attached to a creature, put two charge counters on Flintlock Pistol." (-0.5).
This was intentional. Lots of cards in my set had "attach" effects (e.g. Balan, Wandering Knight), so I had phrased it as such in order to correct for those types of effects. This would normally be something in the design notes, so I am less upset about this than I am about the flavor, I had just wanted to offer my rationale here and ask for future contests how one might try and do something a little bit less than normal without being docked for it.
Anyway, to be clear, I am not mad or upset. I am disappointed in the flavor side of my card being docked "on principle" that a multibillion dollar company is too scared of its image to print cards with firearms on them, particularly since forum cards do stuff like this all the time when we don't have shareholders to answer to. (See all the Star Wars sets out there) I hope Wizards loosens this standard a bit in the future, because it does strike me as incredibly inconsistent, but se la vie I suppose.