I want to study MBBS /BDS/vet from west Bengal... my neet score 300..sc cat...can I get a govt seat?

You still have a hope because for your AIR in common rank list may be 1 lakh to 1.5 lakhs...but your SC AIR will be between 4000-7000. When the state prepares its own merit list, your rank will further be boosted up. For reserved category, 300 is a ok ok type score. Keep hope.
This may help you dear, look at the trends, this is of 2015 AIR trends for opening & closing ranks in WB , which is quite similar to 2016 as well. Have a look :
http://skillguard.com/news/2017/05/10/west-bengal-government-medical-colleges-cut-off-neet-2015/

Chances are very less to get seat in MBBS and BDS course with this score but you can try for vet. if you want as chances should be average for the same.

Good Luck!!!