Does a large caliber rail gun count as a destructive device under weapons ownership laws?

Question

I am planning on building a large caliber railgun in my garage

If it has a bore capable of firing a 30mm dart at high speed, enough so to pass through a vehicle, does it classify as a destructive device, and thus require a permit?

Same question goes for homemade pulse lasers capable of punching through 1/8 in steel...

Hypothetical mind you, but i have the schematics...

Answer 1

Yes it does. And if you use it, you may spend a long time as a guest of the state.

Answer 2

Any firearm other than those recognized by the ATF as suitable for hunting that has a barrel diameter of more than a half inch is classified as a destructive device per the National Firearms Act of 1934.

Answer 3

Under federal NFA law it's not considered a destructive device. Check your state and local laws and ordinances before you continues.