I think Calamity would be more fitting here.  
Him being outcast by his family is as close as can get to Boones edginess of backstory.  
And both are magnificent deadshots.

@redweasel  
At least she isn’t depressed and stoic like Boone.

@Meanlucario
 

>joyful
 

this is super cute and neat! ^^
 
 
despite the fact that boon is replaced by pip

@Tavi959  
And that’s the problem. It’s a missed opportunity to have the cold and sober Boone next to a joyful Pip, two characters who both when through hardships but reacted to them dramatic ways. If the artist really wanted Pip in Boone’s hat, than just have her sitting on his head wearing the hat or next to him after she stole it off his head. That would have been just as cute, if not cuter.

@Depressed Knoll  
Because that’s not the point. The point is putting a hat on a cute pony to make the hat cute and the pony cuter. Personality has nothing to do with it.
 
You are reading way too deep into this. Strictly speaking, Littlepip has suffered a whole lot even compared to Boone in their respective stories. The difference is that she’s not a trained sharpshooter and she’s not a dark, brooding Cold Sniper. She’s had her darkest moments and come out the other side strong. Boone is implied to have passed the despair event horizon, and the only reason he’s still alive is that he wants to kill as many members of the Legion as possible before he dies.
 
If anything, Pip’s stronger than Boone is by virtue of not having lost her sense of self after everything she’s been through.

@Tavi959  
So why not have Lil’pip be joyful on Boone’s head, showing him annoyed and comparing the character’s personalities?

@Depressed Knoll  
I disagree. Pointless crossovers happen all the time just because someone likes a character.

@Tavi959  
My point is, personality-wise, the thing that’s kind of important with crossovers, they aren’t similar enough for this to count, nor even share a similar backstory, so no compare-contrast.

We need more Pip in New Vegas.

Every time I did this quest, Boone would glitch and start shooting at me.

@Depressed Knoll  
The Sniper from TF2 is not a pony, nor is he from a Fallout game.
 
Pip’s not as good a sniper as Boone or Calamity, but she can hold her own thanks to her targeting spell. She’s also adorable, which is arguably the reason she’s here.

@The Toaster Repair Pony  
@Depressed Knoll
 
If I were to make Fallout Equestria (And PH since I ran out of main characters) into TF2, I’d make Pip the Solider, and Calamity the Sniper… Velvet is the medic, Blackjack should be the Scout… since I’m adding the Project Horizons characters, and there aren’t two medics, I guess I’ll make Glory the Engineer. Steelhooves is Heavy, and since Pryo is the closest thing to a melee-focused character I’ll make him/her Rampage. Xenith is the only stealth-focused character so she’s the best pick for Spy and by process of elimination (and since he’s the only explosives expert other than Steelhooves) that would make P-21 the perfect choice of Demoman.

@The Toaster Repair Pony  
So does Sniper from TF2.

@Depressed Knoll  
Pip favors sniping too

Not sure how this works, considering the character Pip and Boone are quite different, as far as I know.