Was able to repair a Wiss aviation snip that my father used at Boeing Aircraft in the 50s &60s. A little sharpening and this replacement spring and we are all good to go!
Bought this hoping to replace the broken spring in my WISS M300 cutter. Thankfully it worked out OK.
Apparently the M300 is slightly smaller than the M2R or M7R. To fit perfectly into the M300, trim about 1/4" off the length of each leg of the spring.
Or not, since I didn't trim the legs and it works OK as is. Beats throwing away a tool because of a broken spring.