I understand your point, but to be precisely true:
Fundamental rights are subject to a strict scrutiny standard, not just a reasonable standard. This means [from Wiki]:
To pass strict scrutiny, the law or policy must satisfy three prongs:
1. First, it must be justified by a compelling governmental interest. While the Courts have never brightly defined how to determine if an interest is compelling, the concept generally refers to something necessary or crucial, as opposed to something merely preferred. Examples include national security, preserving the lives of multiple individuals, and not violating explicit constitutional protections.
2. Second, the law or policy must be narrowly tailored to achieve that goal or interest. If the government action encompasses too much (over-inclusive) or fails to address essential aspects of the compelling interest (under-inclusive), then the rule is not considered narrowly tailored.
3. Finally, the law or policy must be the least restrictive means for achieving that interest. More accurately, there cannot be a less restrictive way to effectively achieve the compelling government interest, but the test will not fail just because there is another method that is equally the least restrictive. Some legal scholars consider this ‘least restrictive means’ requirement part of being narrowly tailored, though the Court generally evaluates it as a separate prong.
I would be very, very happy—would probably jump for joy—if the SC held that the right to keep and bear arms is a fundamental right [which it should do].
If they did, then they'd probably incorporate it and make it applicable to the states -- something we might regret.
Once incorporated, the SC interprets it for all states. For example, the first amendment is incorporated. The SC said nude dancing is "speech" and is therefore protected. All states must honor that interpretation. Ditto abortion -- allowed. Flag burning -- allowed. Under God -- nope. Nativity scenes at Christmas Winter Festival - nope.
Now, imagine 5 liberal justices on some future SC stating that "arms" don't include handguns. Or "bear" doesn't include concealed carry. Or "keep" means in a state armory.
Hey, if they can find abortion in a penumbra of an emanation, they can find anything.
To me, a reasonable regulation of a fundamental right is a law which passes a strict scutiny test. A reasonable regulation of a non-fundamental right is a law which passes a rational basis review.