I've explained the difference. A better gun analogy would be allowing the purchase of an AR-15, but not the M-16. Same gun, different features.
You said they could ban certain types of guns under the commerce clause, but not a particular application of guns, such as deer hunting.
I've looked for your explanation, but didn't find one and still don't see why there is this difference. Setting aside for the moment the argument about illegal drugs, for legal drugs, they are ALSO banning certain applications, such as assisted suicide. Drugs are legal, but only for federally approved applications.
The gun is legal, and must be legal for hunting if the state says hunting is OK.
The drug is legal, but cannot be legal for assisted suicide, even though the state says that's OK, because the Congress says it is not an approved drug use.
So if Congress embarked on a regulatory scheme (to which is due all the deference in the world, of course) to regulate deer hunting by abolishing it nationwide, and they said yeah, guns are legal, but not if used for the application of shooting deer, why would that not supercede state hunting laws?
It seems like, based on your logic, it must. Explain the difference (again?)