I still have a X2 mini but it is relegated mainly to milling brass and aluminum. You will need a much stiffer machine if you are going to mill steel receivers and parts. Sounds like you are looking for a table top model. There are lots of Tawain and mainland chinese models out there to choose from. Anyone will tell you a used small bridgeport is way better than a new chinese mill but if you need to set down then thats probably out of the question.
A few sites to look at
www.use-enco.com
www.smithy.com
www.grizzly.com
www.harborfreight.com
www.taigtools.com