1974 Quarter

Hmm...odd, I had a similar experience the other day with a bicentennial half-dollar.
It really made an odd sound when dropped on the table. On my coin, I guessed the cladding was separating somewhere inside.

This is just a guess but I see this often particularly on halves.

If the coins in question (particularly the half) go "THUD" when dropped and sorta sound like a chunk of lead, so to speak, the odds are strongly in favor of them being Magician's coins.

Check the alignment of the obverses to the reverses and see if they appear to be rotated dies. If they appear out of line, suspect Magician's coins.

If the obverses and reverses do line up then there may be a separation in the clad layers that allows there to be a little air between the layers that would disrupt the proper ringing sound of the coin if it were dropped on a hard surface.

Magician's coins can be tough to find the seam on as it is usually just inside one rim of the coin and with a little wear becomes difficult to see.

Thanks,
Bill

If you want to, let me know what you see with respect to rotation.