Okay heres the deal, but I can ONLY provide an answer based on the info you provided!!!!!!
1) You mentioned a "50 amps" so heres the voltage drop according to a formula I found (NO WARRANTY I did this in a hurry) and the data you provided:
If you use # 2 AWG Copper Wire 220 feet one way from meter to load 50 amps of current VOLTAGE DROP 3.53 Volts Percentage Voltage Drop 2.9%
If you use # 1 AWG Copper Wire 220 feet one way meter to load 50 amps of current Voltage Drop 2.8 volts Percentage Voltage Drop 2.34%
OF COURSE, NO 6 WIRE CAN HANDLE 50 AMPS BUTTTTTTTTTTTTT YOU SAY 220 FEET AND YOU ARE CONCEREND WITH VOLTAGE DROP, SO AT 50 AMPS IM ONLY ANSWERING YOUR QUESTION AND CONCERNS REMEMBER !!!!! If you wanna just use 6 or 4 gauge AND LOCAL AUTHORITY ALLOWS IT OR THE LOAD IS ACTUALLY LESS (in which case smaller wire suffices) ITS YOUR MONEY AND YOUR CHOICE
NOTE When I was a design engineer I didnt like over 2% in Voltage Drop I.E. you would need even bigger wire, 1/0 yields only a 2.21 volt 1.85% Voltage drop
NOTE If your actual load is less then 50 amps, then, of course, the wire size can be reduced, BUT YOU CANT MAKE THIS CALCULATION WITHOUT KNOWING THE LOAD, SO BEWARE OF BILLY BOB AND BUBBAS ADVICE AS TO WIRE SIZE (considering voltage drop) WITHOUT KNOWING THE ACTUAL LOAD!!!!!!!!!
2) Okay you stated from your "electric meter" to the shed NOT from any Main Distribution Panel out to what would be considered a "Sub Panel"
NOTE if thats the case, for a 120/240 volt single phase three wire service from the meter base out to the shed YOU CAN GET BY WITH RUNNING ONLY THREE WIRES (L1, L2, Neutral) just the same as you only run 3 wires from a service transformer to your meter and meter into main panel.
HOWEVER if you run from the homes main distribution panel out to a "sub panel" in the shed THEN YOU NEED FOUR WIRES (L1, L2, Neutral, Equipment Ground) and at the sheds "sub panel" keep the Neutral and Ground Busses SEPERATE AND ISOLATED FROM EACH OTHER
3) SUBJECT TO LOCAL AUTHORITY RULES NOTTTTTTTTTTT ANYTHING SAID HERE You may get by using direct burial rated cable like UF Underground Feeder or USE Underground Service Entrance and again for 120/240 volt single phase three wire service 3 CONDUCTOR FROM METER TO SHED OR 4 CONDUCTOR TO SHED FORM HOUSE MAIN PANEL
4) If from meter to shed, at the sheds panel the Neutral Buss is bonded to the Ground Buss and the Neutral Buss has a No 4 "Grounding Electrode Conductor" ran outside and attached to a "Grounding Electrode" which may be a "made electrode" such as driven copper rod or rods (SUBJECT to Local Authority Rules NOT whats anyone here including myself thinks, especially Bubba and Billy Bob lol) and other suitable approved grounding elecrodes such as metallic water pipes and structural foundation steel etc etc.
NOTE check with local authority because I have seen the Neutrals grounded 1) Up on the weatherhead service riser 2) in the Meter Base 3) Inside the Main Panel SO THE ABOVE MAY BE WRONG IF THE LOCAL AUTHORITY WANTS NEUTRAL GROUNDED IN THE METER BASE !!!!!!
5) If youre running from a main panel out to a sub panel, you still need a "grounding electrode" at the shed remember, its just that you need to carry 4 instead of 3 wires and at reh shed Neutral and ground are NOT bonded but seperate and isolated
Okay I do my best to give an answer based on THE INFO YOU PROVIDED........BUT LOCAL AUTHORITY IS WHAT COUNTS, NOT WHAT I OR OTHERS THINK....And I havent designed in years and am rusty on the latest codes SO NO WARRANTY, but I do my best........
You asked what you need for 50 amps and were concerned with VOLTAGE DROP, so thats the answer I gave you. I wouldnt run any less then a 60 amp 120/240 volt service if it were me and even better a 100 amp SO YOU HAVE TO SIZE YOUR WIRE TO MATCH THE LOAD NOTTTTTTTTTTT WHATS GUESSED AT HERE.
I know I left a lot out, so if any other experienced electricians and engineers here can add to this or correct me Id sure appreicate it.......... John T Too long retired EE and rusty on this but like to help the best I can