It's as easy to smuggle guns into the US as it is to smuggle in drugs that aren't grown there. It's also pretty easy to manufacture them. I suspect the latter is just your perception from never having tried.
I don’t know much about gun smuggling. Do you have sources or experience in this area to know that gun smuggling is as easy as drug smuggling? My impression, not based on experience, is that gun smuggling can’t occur at near the level that drug smuggling does. For one it’s far easier to track the manufacturing of guns as the location of factories is well known and public knowledge.
Is it your contention that any old fool like myself can produce useful guns (ones that don’t explode when I shoot it) and ammunition? Does this ability scale the same way that growing marijuana does?
You might know where the factories are, but what does that matter if manufacturing guns isn't illegal in those places? At present, guns are smuggled _out_ of the US quite effectively [1]
As for whether it's easy to produce a working gun: well, generally you can purchase the component parts of a gun on some continuum between raw materials and final product. The exact point on the continuum that you make your purchase depending on your risk level and how restrictive gun component laws are where you live. After that it's a case of following schematics and a little machining skill.
However, it seems unlikely that individual criminals would manufacture their own guns, in the same way that drug users don't typically manufacture their own drugs. It would require investment into machinery and minor expertise, but the barrier to entry is low enough that suppliers shouldn't have much problem stepping in to meet demand. I would assume that the US has the highest prevalence of gunsmithing expertise of almost any nation at this point. Those skills won't vanish overnight.
If you're really interested in making a home made gun, without involving a supplier, there are already ways to do that [2]. It seems unlikely a ban on 3D printing or other machinery and raw materials would work out.
I’m aware of 3D printing. At this time it is not ubiquitous or cheap enough for mass consumption. When it becomes so then the comparison to the drug trade will become more apt.
There are lots of examples of countries with effective illegal drug operations and effective gun control. Therefore the belief that banning guns will necessarily be as effective as banning drugs is provably false. As such it’s a poor argument. There are lots of valid reasons to believe that banning guns in the U.S. won’t work.
Is it your contention that any old fool like myself can produce useful guns (ones that don’t explode when I shoot it) and ammunition? Does this ability scale the same way that growing marijuana does?