IT SHOULD HAVE been obvious a few years ago when people began wearing camouflage fatigues and combat boots to the supermarket what the next step would be: they'd want the weapons to go with their outfits. Apparently some are getting them. According to an estimate published in Newsweek, there are about 500,000 assault weapons in private hands, and approximately 125,000 of them have been turned into machine guns by home handymen.

There are no special federal restrictions on the sale of popular semiautomatic weapons such as the AR-15, which can fairly easily (if illegally) be converted into an automatic weapon like the military's M-16. Another popular gun is the little Uzi, which Newsweek says has a top firing rate of 600 rounds a minute. There's a firing range in Georgia where men and women blast away with machine guns at such items as bowling pins and posters of the ayatollah. In time maybe this sort of thing will get to be as common as pottery classes.

It can be argued that 600 rounds a minute is a strong discouragement to criminals. The argument loses some of its force, though, when you consider that criminals are also acquiring assault weapons and, in some parts of the country, are using them with alarming frequency.

Meanwhile, the possibilities grow for a dramatic escalation of the average neighborhood dispute over a stolen skateboard or a parking place. Consider the following fanciful scenario: Mrs. Hatfield, just back from a session at the firing range, confronts Mrs. McCoy from across the street over damage done to somebody's rose bushes by somebody's dog. Mrs. Hatfield absentmindedly punctuates her argument with a warning burst from her Uzi, awakening Mr. McCoy inside, who jumps up, shouts "This is it!" and rakes the other side of the street with a blast from the living room. Mrs. Hatfield retreats under covering fire from her neighbors, while in other houses along the street families are assembled, issued weapons and told: "The day we have been training for is here. To your posts. We're at war with the other side of the street."

But enough; this is ridiculous stuff. Almost as ridiculous as the idea of people keeping Uzis in the broom closet and a national government that seems to think there's an unrestricted right to bear AR-15s.