We use alot of Electreat 50 from The Steel Supply Company. We use it for guide rods and piston plungers. We just machine the ends, (threads or keyways), and go.
They don't show this grade on the web site but you can call and request a buyers guide.
Electreat 50 is 50-60c rockwell and you can machine it fairly easily.
You probably would use a carbide drill, but you can get away with cobalt. If you slow things down.
It has a hard case, 115,000 KSI tensile, 100,000 PSI minimum yield, precision ground or chrome plated.
They also have #2 piston material, ground and chromed.