dummy magazines

how would one go about converting a 5/30 mag into a dummy mag?

loaded with 30 dummy rds with all components of a magazine including follower and spring and whatnot, but is pinned or fixed in such a way that no rounds can be fed and all 30 rounds are fixed into the mag.

I have a project I'd like to get into for translucent mag or something similar for display but I'm asking the noob questions here first to tackle the legality of undertaking such a project.

Not sure about the legalities of the issue.

I don't think you can load 30 rds due to spring tension. My guess would be maybe 25 rds then you weld a piece of metal over the ammo in the magwell. This will seal off the rounds permanently. You can still see them from the transparent side.

Personally, I don't see why it won't be legal if the mag is sealed off but who knows about our dumb laws!

With our dumb laws as soon as your mag is "unpinned" it's illegal whether it's empty or filled with anything it's the "unpinned mag" that becomes illegal