The adaptors with a side oil port do not meter their oil dose. You'll shoot most of the oil out in a single mag fill. The reason I recommend adding oil to the propane tank once every eight mag fills is that heavy lubrication is not required. Overlubing results in your gun getting the drips. Adding oil to the filling cycle gets oil inside your mag which also maintains the seals in your fill valve and fire valve. External application of lubricant does not do this because oil does not reach the innermost seals on your fire or fill valves.
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