I would say that with out a doubt a 130 is big enough for deer. The difference between 130 and150 is the 130 will be flatter shooting being faster, way faster than the 30/30. The 150 will deliver more energy being heavier. velocity X mass = force. The 243 for deer would be between 90 and 117 gr and will do a fine job out to about 250, 300 yards. Shot placement is the key to any caliber and bullet. The difference in drop between the 2 weights you mentioned at 150yards probably wouldn't be more than 1 inch difference. The rifle being new to you, your goal should be to find the bullet that gives you the best group regardless of the weight. that way when you make that 200 yard shot you are confident that bullet is going where you put it. Just guessing but 1 inch high at 100 would make you between 3" and 4 " low at 300yards. Outstanding deer gun.