Now that's what reloading is all about....Congrats!! You are right about the 5-shot groups. They will usually give a better idea of a load's potential. Temperature and humidity changes are important factors to consider too. Often a load that shoots well in 60 deg. weather will cause problems at 80 deg., and vice-versa.
You are probably going to want to try those tight groups at longer yardages to see how they perform "out there". Just some things to consider... But, it sure puts a smile on your face to know you've got something good going, doesn't it??
Keep on pluggin'..........