Reloading is an addiction and fun and doesn't hurt anyone and keep you off the streets, so why not. DO IT...
To begin, hit the gun shows and pick up 3 or 6 or 9 or more used reloading manuals--different brands. Each presents the basic steps. STUDY THEM CAREFULLY. You will find one that is more "clear" to you than the others. The old data is useful for comparisons, but you want a brand new manual for brand new data for current production components. Buy the brand of new manual that you decided you like the best.
It ain't hard. You knock out the old primer and squeeze in a new one. All the time you are examining the case for problems. You need to squeeze the lubed case down a bit so it will go back into the chamber and hold a bullet tightly. (Resizing.) Then you weigh a powder charge, dump it in, and squeeze in a bullet. Saves 30 to 60% and can be alot more accurate...
Costs??? Lee Hand Press and all other components for a factory caliber, dies, scale, lube, chamfer tool, --under $100.00. Cheap enough and if you don't like it you ain't out much and if you do you will be spending money trying things the rest of your life... (addiction!). You don't need a Rockchucker press to start (although I love mine, started with RCBS JR. Corbins.com has the Rolls Royce of presses...
Now you mention .25/'06 AI. Great choice if you are not going p'dog shooting. Little hard on barrels rapid fire. BUT you will need custom dies. Huntingtons.com and ch4d.com have them. Maybe LEE. Maybe redding/ Hornady. Maybe Lyman. But they cost more. I would guess most of $100.00.
As said, the "sop" (Standard operating procedure) was to set the barrel back one thread / one turn (so the sights are back on top) and cut the chamber to be tight on factory ammo. (No sights and 1/4 to 1/2 turn is enough...) With the fixed barrel rifle this is not worth the effort/cost, so to establish headspace for something like the .25/'06 AI, you neck up to .270 (.27/'06 really) OR .280 (.28/'06 almost) OR .30/'06 and neck back down so the case headspaces on this little shoulder at the base of the neck, "jam fit" to prevent case stretch and great potential for head separation. Probably want to anneal necks alot sooner...
The other option is to seat the bullet out and into the rifling... No one likes this much, but it does work... Or oil the case... again, poor practice, asking for trouble...
PLEASE UNDERSTAND: If you shove the case all the way forward with the firing pin and the neck grips, then the base has to shove back under pressures of firing and stretch the body of the case. One shot and this is no big deal. Many militaries have plenty of headspace. If, however, you reload and full length resize and shorten the case and it has to stretch again (and again) you are asking for a pull apart. ["HEAD SEPARATION" ] And with a single shot you will need more resizing. Bolt guns have an 11 to 1 leverage at bolt turn down if I remember right... (Memory is going with hair...) POINT: If you pull a case in two during firing, you have hot gas at 2 or 3 times the temperature of a cutting torch loose. It only takes a tiny piece of anything blown into your brain to end YOU! And if you are not LUCKY, then you wear dark glasses while they rebuild your face... AND keep the dark glasses the rest of your life -???- Being CAREFUL, much CAREFUL is so much easier on all of us. Please do. enjoy... luck... happy trails...