You probably already know this but just in case and a reminder for others;? Are you using an active circuit true peak reading (pep) wattmeter to monitor the output of the 301?? On a regular wattmeter like a Bird 43 that doesn't read the peaks you will only measure average power which is 10-30%, depending on the voice, of the actual power the transceiver is developing on voice peaks.
The 301 makes full power nicely using the hand mic that was originally supplied with the transceiver.? I have found other mics generally lacking and in need of a preamp.? A D104 crystal mic works great when followed by a FET used as an impedance converter to go from high to low impedance.??
https://www.w8ji.com/d104_to_low_impedance.htm
