Had ridiculous feeding issues with the stock magazines that came with my Remington 597. Bought these upgraded MCarbo springs, installed them in my old factory mags and they feed flawlessly!!!
What's more, after seeing the price of new magazines, I found a free STL file online of the Remington 597 magazines. Downloaded the file, then sliced it with a slicer program and uploaded the file into my 3D printer.
I 3D printed my own magazine with ABS filament and installed this MCarbo spring. Wow! Feeds flawlessly after a little sanding.
The price of a 597 magazine is ridiculous and I just created one for the price of the spring! The best spring on top of that!
*1st pic: the 3D printed mag on the left, new mag on the right
*2nd and 3rd pic: old factory mags cleaned up with MCarbo springs installed