Try e-gunparts.com
You will need to find out who made it first.
Try e-gunpartsl.com
On www.FirearmsGuide.com
If you have taken it down farther than you can remember how to reassemble it, it's time to take it to a gunsmith. If you are determined to do it your self, there are several books on shotgun disassembly/reassembly. Check out DBI publishing or Amazon.com to find one which has your shotgun.
No-one seem to have a diagram on the repeater but I did find this on the web. see the link below
I am not sure about the diagram,but I would check at numrich gun parts corp. first for the parts you need.
J.C. Higgins is an old brand name used by Sears.
Many different makes, models and designs. Start with Google.
Try e-gunparts.com, gun shops, gun shows, want ads.
i need a diagram of the internal parts of this gun. where would i find it..
Best left to a trained gunsmith.
numrich gun parts has breakdown drawings and assembly steps