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_23430 ( "Colt model no." text, "Military designation" text, "Barrel Length" text, "Barrel" text, "Handguard type" text, "Buttstock type" text, "Pistol grip type" text, "Lower receiver type" text, "Upper receiver type" text, "Rear sight type" text, "Front sight type" text, "Muzzle device" text, "Forward assist?" text, "Case deflector?" text, "Bayonet lug?" text, "Trigger pack" text )

### Question ###
What is the rear sight type on the model with the acr muzzle brake device?

### Accurate SQL ###

SELECT "Rear sight type" FROM table_23430 WHERE "Muzzle device" = 'ACR muzzle brake'