Well things got dry around here finally yesterday afternoon so maybe by tomorrow the range won't be a total mud hole.
We got the screw/shaft heat treated to a place we like but it not a process not easily done at home. A small temperature controlled oven that will reach 2000 degrees is a must. We used some temp indicator crayons from McMaster-Carr at
http://www.mcmaster.com to get the proper temper after hardening the screw/shaft by heating it to nice cherry red and dropping it in quenching oil at my friends shop. This makes the unit very hard and brittle. I think he used a 1800 degree crayon for that. I was not there for that part. We then found that if we heated the hardened unit to 450 degrees and then quenched it we wound up with a tough screw/shaft that was not brittle. We used the 450 degree temp crayons to make sure of our temperature. When the crayon color turned brown, out of the oven it came and into the oil. We did ruin two screw/shafts in the process. One we had too brittle and the other we are not sure what went wrong. Both broke.
On Friday I turned down a couple of Allen head cap screws to the correct diameter and length and then threaded them on my Unimat lathe. It was raining hard so I had more time on my hands. They did not need heat treating as they were already tough enough.
The heat treating process we did was very precise and is easy if you have the right equipment. Without it, it would a guessing job and I am not sure how that might come out. I have done things like this with an oxy/acetylene torch in a pinch and the crayons will take some of the guess work out. I just worry about someone not getting it right and ruining a screw/shaft and having to buy a new mag. I have access to stuff at home and my friend has everything else that I don't and then some. He is even thinking about making a batch of screws for club members and beyond. Again, retirement and too much time to play.
In the end we now have 8 very nicely functioning mags. When things dry out, I plan on going up to the range and running a few dozen rounds through my 5 and see what happens. They so far they work very slick with dummy rounds, so I am pretty confident they will work nice and slick with live ones. Recoil is the only wild card my friend can foresee.