Can you own a long gun with a juvenile felony?

There are a lot of dependencies. You can have it erased from your record. However in order to receive a gun license you will undergo an extensive background check that could bring up an erased felony. If you have let's say attempted murder, don't bet on being able to legally own a gun. But then again they might not be able to find out. Just don't count on it. If you have a felony like GTA, they might look at your tax record, any other offenses, etc. Know that there is a person who judges your character to see if you're the type of person they could trust with a gun.

http://www.cga.ct.gov/2006/rpt/2006-R-0212.htm

Short answer: Maybe.