Is it overly broad for me to say the "non-class 3' crowd generally don't know what they're talking about?
probably not, provided you recognize that there are exceptions. And this seems to be true with any and virtually every technical area. The "non-crowd" usually only knows hearsay and stories. And some of those stories are deliberate lies, that only people involved in the subject actually recognize.
And with guns, its even worse than many if not most other subjects.
Can't begin to tell you how many people have told me, over the years, and with complete honesty and faith, that, to get your semi auto to shoot full auto, all you have to do is "file the shear pin". They know this for a fact! They can't tell you what the "shear pin" is, where it is, or what it does, except that if you file it, your gun will shoot full auto!!!!
I'm part of the non-class 3 crowd, I don't own any NFA items. On the other hand, I used to repair machineguns for Uncle Sam, and I have shot them a bit...also understand the designs, features and functions common to full auto and select fire weapons, individual and crew served. Perhaps I'm an exception??
What I don't know as well as the class 3 guys are the details of the paperwork involved in civilian ownership. The guns, I know fairly well, and much better than the crowd who gets their wisdom from a TV screen on such matters.
Since so few people have actual hands on experience shooting machineguns, rumors, half truths and outright BS about them abound.
One of my favorite BS stories, and one almost universally believed, even by people who have actually shot one (once), is the myth about how the recoil of a Tommygun causes the muzzle to climb. (and climb up and to the right according to some, to the left for others...)
That IS what happens when undertrained shooters fire the Tommygun, but it isn't the gun doing it, it is the shooter.
Other than the fact that it is FUN, full auto has very little practical use, none for big game hunting, (even if it weren't legally prohibited) although an FA .22LR would make a nice pest gun, pest eradication & predator control isn't sport hunting.
Now, Select fire is a different matter. Although legally machine guns with all the restrictions, select fire allows full semi auto "utility" with full auto capability kept in reserve for "gravest extremes" and for those times you just want to rock & roll for fun.
In a way, select fire is the most modern iteration of the old US Army concept found on Krag & Springfield bolt actions, the magazine cutoff. The base idea was that you fired single aimed shots (reloading the chamber each time) and kept the loaded "high capacity" magazine (5rnds) in reserve for emergencies when rapid fire was needed.
