I use Super Lube on my internal lock parts. It is a synthetic multipurpose lubricant/grease, is highly lubricious, clear and non-toxic. it includes PTFE micro powders that provide longer life protection against friction, wear, rust and corrosion. It will not run, drip, evaporate or form gummy deposits. Nor will it melt or separate. It is dielectric and impervious to salt water. It retains is viscosity between -45F to +450F degrees. If interested, google 'super lube' to see other information on it or where it can be purchased.
On my external lock parts, such as the frizzen and frizzen spring, I use Track of the Wolf's mink oil for a lubricant.