I would just say don't put a bearing in. Boom, no oil needed
Sent from my SM-G930V using Tapatalk
If the bearings are seizing up you may want to some oil once in awhile. I doubt Tuna used sealed bearings so I would remove the trigger and lay it on
The bearing really makes no difference other than adding a level of complexity that is not needed, and to give it the appearance of being a high-end product.