Try e-gunparts.com, gun shops, gun shows, want ads.
Yes, 380 or 9mm from a model 58 or 59 is the same pin...
You need a gunsmith.
http://bryco-jennings-jimenezarms.com/forum/viewtopic.php?t=541
On line auctions.
The barrel on a Bryco Model 59 .380 caliber pistol cannot be replaced with a 9mm barrel because they are different dimensions. The internal components are also slightly different due to a difference in caliber.
Hi I've got a Bryco' 59 9mm handgun and it works well. I had this gun for over 10 yrs and i have paid around $250 . I am guessing it's worth now about $200
Try here http://stevespages.com/page7b.htm
Best to ask a gunsmith for help
Take it to a gunsmith
Try e-gunparts.com
Take it to a gunsmith and ask for help