With the forend removed, will it lock up better? If the forend stud is not on straight, it can affect latch engagement, causes the one sided latch engagement, but that's not real common and an extreme. If it has an NA serial number prefix or later, H&R will fix it, or you can fix it yourself with the barrel fitting info in the Centerfire FAQs if it's not the forend stud issue. Their toll free number is (866)776-9292.
Tim