Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_12834315_2 ( barrel_length VARCHAR, name VARCHAR )

### Question ###
what are all the barrel lengths whith the name ar-15a3 competition hbar

### Accurate SQL ###

SELECT barrel_length FROM table_12834315_2 WHERE name = "AR-15A3 Competition HBAR"