Hi:
"Timing" is a poor term on a Krag. You are doing two things, getting the front sight perpendicular and getting the extractor cut in the proper location.
Almost all of the rifles mentioned were made on manual machines as fast as possible for war time production. The last Krag was made around 1900. Their idea and today's ideas of tolerance are pretty different. What most of these experts forget, is all of the rifles mentioned were final head spaced by swapping bolts out. Chambers and bolts were made with lots of variance due to the speed for war production and tools available. The guy barreling or re-barreling had a bucket of bolts and swapped them in barreled actions until the gauges said O K. English Enfields had removable bolt heads that came in different lengths - 1 to 5 to head space.
I have shot a lot of Krags, Springfields and M1's (worn out many barrels). I have changed several barrels. They usually have a witness mark on the action and arsenal barrels. You screw in until the marks line up. Some screw in easily and some don't! Sometimes you have to cut the barrel face where it meets the action face to screw it in enough and sometimes you end up lapping the threads in to get them to fit up. Most of the time the head space is off. If the chamber is short, just sink in the chamber with a reamer. If too long you have to cut the chamber face on the barrel and sometimes the cut the chamber end of the barrel (cone). Re-chamber to Sammi specs. Do not shoot a military rifle that has had barrels swamped with out testing with head space gauges. I have had the pleasure of having an M1 fire out of battery (twice). It gets very exciting and loud! Digging the brass out of your face is less fun.
Kreiger barrels has a subsidiary company called Criterion Barrels. Criterion makes very high quality button rifled barrels contoured, threaded and parkerized for a Krag for about 225 bucks (also M1 and Springfield). They also have the sight cuts and extractor cuts in the barrel. They are short chambered so you line up the extractor cut & front sight, unscrew and final chamber. If you are using a scope, cut off the first inch or so and line up the extractor slot. Barrel Link:
Civilian Marksmanship Program eStore
I wish the Krag guys lots of happiness and luck swapping barrels. Remember most of them do not understand fits, tolerances and how small a couple of thousands is.
Well I guess someone put a bunch of quarters in my "on button" slot. For better or worse, that is my 2 cents worth.
George