How is seniority between NCOs of the same rank determined?

It's date of rank. When both dates of rank are the same, then total active federal service (BASD).
It's in AR 600-20 Army Command Policy

TIG takes precedence over TIS. If those are the same then it goes to TIS. And as a kicker, of both of those are the same then DOB is the determining factor. Reference AR 600-20 The Army Command Policy.

SSG (Join to see) Rally Point generally considers it’s members to have a little more knowledge than you have expressed!

For officers it’s date of rank. Should work the same for NCOs.

For the record, I had told him it came down to TIG, but he said different. Was mainly looking for others to prove my point

Starting at the top, working downwards:
RANK
TIG
TIS
DOB

It is TIG or position. If I had two E5's and one was team leader or squad leader then TIG didn't hold as much weight. That being said just treat each other with respect and you will stay out of trouble.

TIG then TIS

TIG; by the time I retired I think I was the ranking SSG in the Army. I was certainly one of the few that had been a Spec 6.

I'm currently an E-6 in the National Guard, with all my schools completed. SSD and SLC and second on the promotion list to E-7. Right now I have a E-6 rating me, that out ranks me by time and grade. I have no problem with this. The problem I have is this, the E-6 is non-promotable, flagged for ABCP, and PT. In National Guard Aviation, E-6's in the same shop and two other shops are competing for that E-7 slot. How is this even allowed to have a E-6 rate another E-6 going for the same position. How is this not a conflict of interest. This guy could rate me badly just because he doesn't want me to slide into that E-7 slot. I'm not saying this guy will rate me badly but sometimes in the guard your waiting for someone to die for this slot and this person could make or break you for your career progression. Anyone else understand what I'm talking about. Please Leave your comments.

Thanks