As a professional tool and die maker and shop owner, I'd say you are in over your head. A'Farm shop milling machine and a few skills' won't cut the mustard and you'll screw up your barrel, but it's yours and a new one can be bought and taken to a competent machinist/gunsmith and done properly.
There is a whole lot more to fluting a barrel blank that jut a ball mill and milling machine.
It distills down to 'pay me now ot later' scenario.
Put another way, I have a 'few skills' as well and I wouldn't attempt fluting a barrel because I don't have the proper machinery to do it, not do I have the correct fixturing.
I worked with a guy that brought in a Remington heavy barrel in the shop and fluted it with an old Barber Coleman hob!! He used a standard gear cutter, and the flutes were pretty, but the slight taper created a headache he never quit overcame. Took him about an hour after he got everything setup with a very light cutting load. Called me down to show it to me while it was still chucked up in the hob. Then he removed it, and found out that he'd made a serious mess of things! The barrel must have bent a quarter inch! I actually straitened it to within about .005". He then took a very fine pencil torch and got it within a thousandth. Barrel went from shooting half inch groups to two inch groups in a .308! And that was after a complete recrown and a heavy bead blasting. Four hundred dollars later he was back to shooting in the half inch range again, but he did own a good tomato stake.
gary