There is only one problem with any center conductor that sticks out more than 5/16 to 3/8 inch beyond the center white insulator. In the days of hex crimp connectors, it din not matter. With the SNSIT or the SNSUTL tools that fits into the annular slot of the barrel of the compression connector and forces the plastc sleeve between the outer jacket of the coax and the barrel of the connector, again, it doesn't matter.
But, there are a whole lot of compression tools that pushes on the inside of the barrel and the floor of the nut to compress the connector. In this case, a longer center conductor will bottom out onto the floor of the center hole of the plunger on the compression tool. As the compression connection is made, this forces the center conductor and the insulator over it into the coax. Ideally, the insulator on the center conductor must rise above the floor of the connector inside of the nut about 1/32 to 1/16 inch. This protruding insulator impinges on the insulator of the female F81 connector to form a gasket like seal. A space would be present, if the center conductor was forced below the floor of the connector. This space or air gap is where water vapor is most likely to collect and corrode the connection.
So, it is wise to snip the center conductor to 5/16 and no longer than 3/8 inch, check the connector after compressing it so that the center insulator is not below the floor, and to see that no stray shield wire is wrapped around the center conductor.
But, there are a whole lot of compression tools that pushes on the inside of the barrel and the floor of the nut to compress the connector. In this case, a longer center conductor will bottom out onto the floor of the center hole of the plunger on the compression tool. As the compression connection is made, this forces the center conductor and the insulator over it into the coax. Ideally, the insulator on the center conductor must rise above the floor of the connector inside of the nut about 1/32 to 1/16 inch. This protruding insulator impinges on the insulator of the female F81 connector to form a gasket like seal. A space would be present, if the center conductor was forced below the floor of the connector. This space or air gap is where water vapor is most likely to collect and corrode the connection.
So, it is wise to snip the center conductor to 5/16 and no longer than 3/8 inch, check the connector after compressing it so that the center insulator is not below the floor, and to see that no stray shield wire is wrapped around the center conductor.