I don’t know about glass beading “fine” gun parts. My glass bead cabinet was purchased for automotive/motorcycle/bicycle work, and any gun work that was done in it was to pumps that were rode hard and put away wet, decades before I got them. I’ve run black slag (aggressive as hell) aluminum oxide (pretty hot as well) and glass beads. My cabinet has a hinged bottom, that allows for quick abrasive changes, but, I had to learn to get all the aggressive stuff out before going to glass beads, as you end up with glass beads mixed with something hotter if you aren’t thorough in cleaning the other stuff out. For purely gun work, I’d likely stick with glass beads. You are also going to need to think about your compressor, a glass bead cabinet takes as much as an air file or a DA sander. I have a Quincy two stage QT 5 pump driven by a Baldore 3 horse single phase 1750 RPM motor, with a magnetic start off the pump control. I would advise you to stay away from the 3200 RPM special service motors that seem to come on the home owner versions of compressors these days. Do not think you are going to run a cabinet on a single stage compressor, you will end up with wet media, even with in line filters. It is important to have drained gravity drops in your manifolds that lead to whatever filtration/regulation you are using to allow you to get some of the liquid moisture out of the system. I’ve shot a lot of automotive paint out of my system, and did that work before I bought the cabinet, so, air supply/regulation/filtration issues were pretty well sorted. The cabinet was a natural fit for car stuff. I use a doubled up piece of old hardware cloth to sift big crud out of my media, and a junky shop vac to collect the dust from blasting.
Back when I was building a motor or two, here and there, I would rent a parts washer from the Safety Clean route salesman, usually intending to have it around for a month or so, but, the dang things were so handy to have around the I’d extend the contract, often for months. Gentle cleaning that doesn’t tear up the surface, really good for non ferrous parts. it is nice to have both options on hand, but, not always practical. The guy shows up and services the solvent on a regular schedule, and his solvent is the best.

Good luck.

Best,
Ted