You can still season your barrel before shooting it... it helps on cleanup because it keeps fouling soft, improves velocity and reduces friction! However, if you shoot sabots & copper bullets, you need to use a nitro-type solvent to remove it.

Major gun oils are not petroleum oils. Good ones like Breakfree CLP, FP-10.. etc inhibit barrel rust and keep fouled actions working longer. I recommend removing the seasoning when you clean... re-apply it before shooting. Store your rifles with gun oil... not the seasoning agents out there. Bore butter will hold-up in a climate-controlled, humidity-controlled environment, but I wish good luck in doing so to shooters who live in a 4-climate atmosphere with up & down temperatures & humidity like here in Michigan and continue to store their rifles with bore butter in the barrel.