If your casting these your self , you can " beagle " the mould. Basically you add some small strips of aluminum tape to one side of the mold block.
Don't worry about them being out of round. I cast for a 35 marlin with the mico-groove barrel. I beagled a rcbs mold so I could size them to .360. 1.5" - 2" groups at 100 yards, no leading. The bullet will squeeze " round " when sizing or in your barrel.
Powder coat is soft, if the bullet doesn't fit the bore , I don't believe PC will help. If buying your cast bullets, I then suggest just ordering the proper size. If its a micro groove barrel, go .002 over slugged bore Dia. Don't go by what it " should " be, slug it yourself- easy., you would be surprised by the difference. ( Google slugging your barrel, beageling ) if your unsure