Oil added to the hopup bucking or the barrel can foul the bucking by swelling. There's no need for silicone oil inside your ammo path at all (inside or out). Oil can effect your hopup also, greasing the BB and preventing the hopup from working properly.
I use dry rifle patches and swab until clean. If there's debris in the inner barrel, I use a small dab of Teflon, silicone spray on the corner of the patch. Swab down, twisting as I go. I don't contact with the bucking and swab out, twisting as I go. Change the patch and swab and twist until the patch is clean, replacing as necessary.
This seems to work okay for me.