I have been doing some reading and decided to plan a pistol build in the furture cambered for 5.45.  What barrel length would be ideal for this round. From what i read it get a bad rep for accuracy due to the sights on aks. Also the other downside wohld be that it is corrosive. I am only going to be using maybe out to 200 or 300 yards at most.

I can't really see a reason why you'd go 5.45 when it's so similar to 5.56 and the surplus is no longer 8 cents a round.  I understand wanting 7.62x39 or 300 blk for .30 cal options, but why 5.45?

Ballistic Advantage had some shorter 5.45 options listed.  Looks like the only thing currently in stock is 14.5" though.  Most of the barrels have dried up with the surplus ammo.  Not much demand I'd imagine.