Very easy fix for that. Any mechanic or gunsmith could think of a dozen ways to fix the present shotguns so that would not be a problem. And the gun nuts are reaching for straws here.
As a gun owner, for nearly 60 years, I see no need of large capacity magazines. They are illegal in most states on a hunting gun, and no advantage in personal protection. From personal experiance, you can back down a bunch of agressive people with a single shot 12 gauge.
My personal opinion? You can have up to 10 rounds in any given magazine. Shit............if you want, you can even have it in a semi automatic weapon such as a shotgun, rifle, or handgun.
But...................no more than 10 rounds per clip. If you can't hit your target in 10 shots or less, you need to spend more time at the range.
It ain't about hitting a target. That has nothing to do with. In the case that you might find yourself using your firearm to protect yourself, you might also find yourself protecting yourself against multiple targets, in which case the more ammunition you have in one clip, the better, and the second amendment is about your right to bear arms to protect yourself and form a militia to protect yourself against an out of control government that's forgotten they work for us, we are their bosses, not the other way around. Limiting the number of bullets in a clip is one of the stupidest ideas to come out of this, and nothing more than another infringement on our rights.