For my recent needs I did this and it might be suitable for you:
http://tukijaverkosto.org/obat/?cid=59
This doesn't include gun details in the main screen but there's even "similarity" search so you can find similar units. Some units have ATGMs as secondary weapons in the OOB so this system is slightly confused with them. You can also limit the year of availability if you want to compare the tanks of certain year to each other.
Also: Here you can d/l the PostgreSQL database dump:
http://forum.shrapnelgames.com/showthread.php?t=46034