Drilling and tapping WILL DESTROY the collector interest/value of your rifle.Both S&K and B square market a no drill mount for the M1903 and M1903A3 Springfield.I have not used these,but have used the S&K no drill mounts for the P14/M1917 Enfield and No4/5 Lee Enfield.If you do go into a sporter project with a drill/tap mount you must also alter the bolt handle to clear the scope and you must employ an after market safety.18 yrs ago I took a sound,but somewhat pitted, Springfield action and built a nice sporter on it.This involved shortening and re-crowning the barrel,polishing and re-blueing the unit,altering the bolt handle,installing an after market safety and trigger guard with hinged floorplate,drilling and tapping the receiver(these are tough buggers to work with),and fitting a sporter stock with monte-carlo comb.It is a smooth and accurate hunting rifle,but when all is said and done I could have had an off the shelf Rem 700 for the same price.I did it as a project and because I always wanted a Springfield sporter.The action I used had no collector appeal,but was a strong and servicable Remington variant.