Cool and fun card. Whip out a ranged weapon and snipe something, its a cool card in idea and practice. it's just not very good.
This is what the card does:
A +1 damage effect, these are hard to come by in a manner that stacks, layer on the Vicious blow and the gun and you're dealing 4 points of damage in one hit. Sometimes the 3-damage attack is good enough too!
Sniper effect. You counter a couple keywords that might increase the risk or cost you an extra action. Ever so often you save an action moving into the enemy, since the enemy might be located to one side or at a finished spot, this then might double up by not making you haul yourself right back again.
You get quite a bit of cool stuff, so that would make it seem like a good card right? 2 saved moves is EASILY worth 2 spent resources. The extra damage. Sounds good? Not quite.
This is a -card-, you gotta draw it, play it, costs money to play and most importantly, it's 1/15th of your deck! characters do not have much luxury in card draw unless their name is Joe Diamond. also struggle with resources.
What I'm getting at is this: Marksmanship is this real cool effect, a timesaver and circumstantial problem solution, doesn't actually do much that you cannot already, no extra accuracy nor grabbing clues or evading or whatever. If Marksmanship isnt immediately helpful, it's a full blown dud! You might draw the enemy yourself, it's engaged with you, a dud! Dealing +1 damage wont let a 2 damage weapon kill a 4 HP enemy, a dud! Maybe you just don't afford it, even if you got the cash you need to save it to pay for the next weapon or ally and the 2 resources will set you back too much, a dud!
So you see how many shades of "dud" the card is? I've toted copies of this cards in my hand in PERFECT scenarios, drawn it even. Rougarou? Miskatonic Museum? Pretty much all of Carcosa? It just isn't helpful enough. In a card game the best decks have as few potential duds as possible.