You should be able to get an AR-15 SBR set up for about half that amount.
I think .40 would work OK -- or at least as good as the 10mm -- if you are limiting yourself to subsonic and pick good, heavy bullets.
For an optic, something like a DrSight or JPoint would be a good choice.
Let me offer you some alternatives, though, if your goal is to kill a bunch of hogs. A suppressed rifle (non SBR), shooting either subsonic or supersonic ammunition, will probably be a lot more effective. One, you can shoot them from further away, and the report (even suppressed will be totally undetectable). You could even use full power ammunition if you were 40-100 yards away (or further). Some of the options include .308, or pistol calibers, etc. This would allow precision and accuracy you can't get with the pistol, definitely more oomph on impact, and the ability to basically drop them as fast as you can get a good sight picture, with almost not chance of detection.