The whole sight tower is canted to the right. Short of going back to KVAR/Arsenal, how do I fix it? The rifle is NIB.
Contact Arsenal.
How long have you had the rifle? If you bought it within the past year (?) Arsenal should repair it for free. If it has been longer than that, they may charge a minimal fee.
Send it back or run a red dot.
Send that shit back. You can do it yourself but its a pain in the ass without the right equipment. Besides, make them fix it. It would drive me nuts to look at a crooked FSB
I know sending guns back sucks but this is their screw-up. Make them fix it.
So yeah, it’s an Arsenal so you can send it back, BUT since you asked specifically about SHORT of sending it back:
Tap the pins out (the punch from the tool kit is the right size) - they’re not taper pins, you can go either way. Lay the rifle on its side, lay the front sight block on a block of wood, then tap them out.
Next take the rifle and put the FSB in a vice with shims of wood to prevent the vice from marring the metal of the FSB. You’re going to tighten it in there, then take a crescent wrench and put it on the frontmost part of the receiver. You may want to put a protection of some kind between the crescent wrench and the receiver. I didn’t and it scratched some paint, but I don’t care so I didn’t bother.
Twist by hand or using gentle taps with a mallet on the end of the wrench. If you only moved it a little, reinsert pins. Otherwise, use a drill bit to take the corners off the now misaligned holes before reinserting the pins.
Now, as you can see, this is definitely in the style of troglodyte maintenance, but it works. I’ve done this three times. I’ll be shocked if nobody comes in and tells you what a bad idea this is and pleads with you not to do it. In the end, it’s your rifle so you need to decide what you’re comfortable with (I pounded the FSB on with a mallet in the first place, so this was just in the same style of “workmanship” :D)
It is probably a good idea to make a small witness mark on the barrel and FSB so you see how much you’ve moved it. Also, please note that if you misalign the gas block and FSB it can cause difficulty inserting and removing the cleaning rod. If it’s fine now, it may be hard when you twist the FSB. You can move the gas block using the same technique - there is wiggle room there because the hole in the gas block is considerably larger than the gas port in the barrel.
Think hard before you decide and go slow if you do it - I haven’t bent anything on my rifle, but that doesn’t mean it’s not possible. This is definitely above field maintenance and into armorer level stuff we’re talking about 
Before you play Joe the Hobo gunsmith, send the thing back to Arsenal and make them fix it.
This way they also know that there is an issue and will hopefully correct it.
I’ve taken a rubber mallet to the sight leaf block many times before to correct ‘cants’ caused by shotty support when pressing in rivets 
Either I’m a brazen idiot, or it gunsmithing isn’t that ‘hard.’
Arsenal sent me an RMA and the rifle goes back Monday. Quoted 4-6 weeks, I think, for repair. The nice lady at Arsenal gave me zero poop about it and was wonderfully helpful. We will see.
That’s good to hear. I have one arsenal ak left. They are usually pretty good on their QC.
That’s not gunsmithing, its just hitting your gun with a mallet 
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Nonetheless, sometimes a mallet is the proper course of action.
What’s the proper “gunsmithing” way to fix a canted FSB? 
That is the only correct way to do it. Align it, drill it out to the next size, and re-pin.
Are you drilling it out to the next size or just, as you say, knocking the corners down to allow the original pins to go back in? If the latter is true, how do you NOT have issues with the FSB “wiggling?”
I’m not trying to call you out, and I’m not a machinist by trade, but I’ve been into fabrication, metal work and mechanical repairs long enough to not quite be able to wrap my head around this.
Thanks for the link. The part where he heat treated the pin was awesome!
Unfortunately it didn’t at all address my question 
He starts the video saying he already fixed the alignment, then spends the rest of the time making a new pin and drilling new holes. How did he twist the FSB to begin with?
This was a Saiga conversion I did, so the holes weren’t even in the FSB to begin with. I don’t have metric drill bits, so they were already slightly undersized. It’s definitely not impossible for a hard blow to knock the FSB off slightly, though.
My experience just working with the (damn frickafrackin’) thing tells me it’d be hard to get that to happen in practice, however. Even without the pins in, the FSB is so tight on there that to be able to move the FSB, you’d have to secure the entire rest of the rifle. If you just hold it and hit it (or set it on something and hit it) the rifle would wiggle or jump, sapping energy from what’d be needed to move the FSB. Add the pins in and it’s even more secure. Maybe I’m totally wrong, though. Who knows?
Oh, and don’t worry about calling me out. If I say something retarded, I would hope somebody stops me before I convince somebody else to do it too
Once the pins are driven out its pretty easy to rotate the front sight.
Not on my rifle In any event, that’s what I assumed the previous poster was using the mallet for. Tapping it over after the pins were out.
Were you assuming he was doing it with the pins in? If so, I agree that’d be just wrong