Or the shotgun section, but I'll post this.
Measure with a rod down the barrel from the bolt face when the bolt is closed. You want to be absolutely sure of the measurement - there are no gimmies, if you're short by
1/32" you're in serious trouble.
You are OK with OAL because the smallest allowable is 26" and you're 28 - although I'd double check that too if I were you.
http://www.atf.gov/publications/down...f-p-5320-8.pdf
.