On the surface, yes, there seems to be an antigun consensus among the Democratic candidates. But if you drill down into the details, there's quite a bit of variation. Beto O'Rourke, for example, would ban the commercial sale of assault weapons, but would let current owners continue to use them "safely and responsibly." Elizabeth Warren doesn't want to adversely affect long-time gun collectors (meaning she wants grandfathering?). Amy Klobuchar seems to be appealing for the Fudd vote, asking of any gun control measure, “Would this hurt my Uncle Dick in the deer stand?” And so on.
One thing I have to say is that all this is going to look very different, on the Democratic side, once the nomination is wrapped up. The Democrats know that the election will come down to the Rust Belt states of Pennsylvania, Michigan, and Wisconsin, and/or the Sun Belt states of Florida and Arizona. Gun owners are a crucial voting bloc in all these states. The Dems can't afford to alienate these gun owners too much, and that's why they're going to fall strangely silent on the issue.