I'm having issues with reloading benches.

It seems it'll often not allow me to breakdown ammo and I cannot figure out why.

I have 90 repair skill and the Jury Rigger Perk, I want to breakdown 12ga Shotgun rounds, the option is greyed out and says "Breakdown 12ga (38)".

So I have the rounds, and the skill, but for some unknown reason it will not give me the option to break them down. I have 20ga shells I really want to make (love my Level-action shotgun!) but can't.

Is there some other reason the game won't allow me to breakdown this ammo? I have options to breakdown other ammo, but not all the ammo I'm holding.

Are you sure they are regular 12 gauge rounds? You can't break down special rounds like slugs, magnums and such.

Yes, they are indeed normal 12ga rounds.