whats the line? *too powerfull*

[tetrasodium]

So my character is a Gun Guy. He runs guns, its his high concept and everything.

So is it crazy for him to always have access to some Big guns. Like Ak47s (Weapon 3) Bear Hunting Revolvers (S&W 500) (Weapon 4?) or a RPG or 50 cal Rifle with incendiary rounds (Weapon 4 or 5?)
I have pretty good resources and craftsmanship.

Should I be spending fate chips for this stuff?
Same thing with special Ammo, I mean if this was me, and the Dresden stuff was real, I would get my hallow points and fill the cavity with silver.

So what I worry about is being seen as "Cheap" or "munchkin-ing", I've had NO problems so far with either of this in my wonderfull group and our excellent gm. Its more of a personal thing.
So for example

I have a 50 Cal Sniper Rife with a Scope, I spend one round Aiming, and use my Stunt "Scope User" which makes it pretty easy for me to pass a Aim roll.
Then the next round, I shoot the badguy, with my guns being 5 *assuming a Rolled a neutral* +2 for Aiming, Plus +4 for weapon, and I spend a Fate point to tag an aspect +2?.
Thats pretty good, Wizard Level to be braggy. But I was wondering If I could throw in a Naval Gazing Maneuver in there? If so what would I do, and when would I do it? Do I do it on the Aiming round, or what?
Also would this be against the spirit of the game?

The question to ask yourself should be  is your powerful gun usage disruptive to the game?  If you were locked in a closet & your friends got jumped by something nasty, would the GM need to use a different scale of critter than if it was any other person in the group locked in the closet but you? If you guys get in a fight, is your impact so overwhelming that everyone else could just stand back and watch you kill it & they might as well since their own attacks are a waste of time... if most of those are yes, then yea maybe you are overpowered.There's nothing wrong with being able to lay all your cards face up and ascend to a different playing field that your group couldn't do more than gawk at from a very long distance telescope.. if they are careful not to get killed doing so.  It's only a problem when you can't keep some of those cards close to your vest in a non-obvious way to stay on roughly the same playing field as your group until things go wrong and hit the fan making everyone pull out anything resembling a trump card... if your trump card just happens to be super effective, so be it... don't worry.  If it's obvious like when an adult ries to play sports with a kid, try seeing what you can do to pull/guide your group up to par.  Sometimes GM's will give a bit more leeway when someone tries to pull the group up onto the same playing field, in a way it makes GM'ing easier since you don't have to redesign plans on the fly as much based on the presence of one player.

[ways and means]

I don't think a guns build is every going to be too powerful especially not compaired to some builds out there, for instance I once did a Geralt of Rivia build using crafting and swordsmanship, I went around with about 15, 10 shift blocks (Quen), 8 weapons rating 8 zone wide bombs (grapeshot) and many , many potions up too the level that I could add +12 to my roll in two turns (two potions of 3 aspects each Thunderbolt and Rook) oh and some magic swordmanship as well.