Do you care if your shaft rusts? Or would you rather more bending resistance?
17-4PH is the way to go. I'v made my own shafts, I'v used Mako shafts, now I'm using JBL shafts and riffe shafts.
Mako shafts are strong and I haven't had a problem with the shark fins rusting; but the tip and the notch rust. The notch rusted so bad it started to bind my trigger mech (neptonics reef mech).
The shafts I used to make were 17-4ph and fairly easy to drill and work with; but I'm able to get JBL shafts with shark fins for only a few dollars more then I cost me to make them after time and the pain in the ass. Riffe shafts are nice and do the job but are a little pricey for me.
If fish are bending shafts then try and get a better shot angle.
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