Hi, I'd recommend contacting the manufacturer. Even if they don't sell them anymore they'd have to have spares for warranty work. They may be willing to just send you one out or you may have to send them the firearm. You can contact fn at 1-800-635-1321 for repair and repair inquiries or you can email them at (info@fnamerica.com). Only other option would be to go to a gunsmith and they can likely find one or find a similar spring that would work. Sorry to hear that happened but hope this helps some.

I would still call fn if no help there I would check Numrich for the part that's where any gun smith would go....

Hi, I would check with local gunsmiths and also check the "for sale" and "wanted to buy" sections of a few FN Firearms Forums as members buy/sell/trade daily and may have spares. Cheers and stay safe!

I did some searching and the only thing I can come up with (Being every site does indeed list this part as discontinued) is to take Edward C's advice with regards to local gunsmiths. My other suggestion would be to check with a site called Gunbr0ker or Ebay. I did find one sold FN 57 parts kit that sold on the bay and it looked to have the mag catch spring you're in need of. You could even message a few sellers of the FN 57 parts listings that are currently up and ask if they have what you need in their parts bin?
Good Luck with your search!!

I would check with some local gunsmiths in your area. If is only a spring, a gunsmith will have an assortment. If it needs more than a spring, a reputable gunsmith should be able to help. Good luck & have a great day!