I drill my own ramrod holes and I do it as follows:
1. Buy a ramrod hole drill from TOW. They sell gun drills for this purpose.
2. Drill 1/16" feeler holes right down the center of the bottom of the barrel channel every three inches or so from the breech to the ramrod rear entry. Only drill in as far as the bottom of the ramrod hole is supposed to go.
3. Cut a ramrod groove in the stock slightly larger than the drill bit. Make sure that it is parallel to the bore of the rifle and that there is no lip where you start the ramrod hole. I take a gouge and start the hole with that just to make sure it goes in straight. As to cutting the ramrod groove, I have done it two ways:
a. use a router and then open the groove up with a plane(I make these) and round file after the hole is drilled.
b. use a gouge, plane(I make these), and round file.
4. I use grooved blocks of wood clamped over the drill bit in the ramrod groove to hold the bit in place. I put one block just back from the rear entry The other block is placed near the muzzle.
5. With the butt stock clamped in a vise and the forearm resting on a support with the ramrod groove up, I start to drill an inch at a time. Every inch, I back off and clean out the drill. I have used both an corded(cordless batteries don't last long) electric drill and a brace. I am not sure it makes much difference, time wise, which one you use.
6. As you drill through a feeler hole, stop and use a piece of wire (David Crisali's depth gauge is great for this) to check that the hole is on center and not drifting up or down. If it is drifting pull on the end of the drill bit such that you move the forearm in the opposite direction. You can change the direction of the drill bit slightly by doing this, but the main determiner is the straightness of the ramrod groove as a guide. Sometimes, the grain and curl of the wood can make drilling a straight hole next to impossible. If you have to breakthrough somewhere, inside the barrel channel is best. You will be in good company there.
I hope this helps some.
Mark E.