Riteshraja, here’s a link to a discussion I was reading about the size of the overhead bin on MD80’s you can refer to and see if you find some useful information:

http://forums.anandtech.com/archive/...t-1384436.html

However, I would still suggest you check with someone who’s traveled on these aircrafts for more reliable information.

As for your second question, the BRX 22” upright is indeed Briggs & Riley’s lightest carry-on in the 20”+ category. It weighs just 7.5 lbs!