What is the difference between the John Deere 6M 200 and 6R 200?

Here is how the John Deere 6M 200 and John Deere 6R 200 compare on John Deere's published specifications:

• Horsepower: John Deere 6M 200 197 hp vs John Deere 6R 200 197 hp
• Pto horsepower: John Deere 6M 200 159 hp vs John Deere 6R 200 158 hp
• Weight: John Deere 6M 200 19180 lb. vs John Deere 6R 200 19621 lb.
• Fuel capacity: John Deere 6M 200 85.9 gal. vs John Deere 6R 200 95.1 gal.
• Wheelbase: John Deere 6M 200 110.2 in. vs John Deere 6R 200 110.2 in.