I know this is a highly contested debate and I'm sure many people will disagree with me since the unsafe range does not mean a manufacturing defect, but rather the possibility of one.

This may be the benchmark on what is considered a safe receiver. The receiver design was then changed at Springfield around serial 1,275,767 where they then used nickel steel alloy and changed the heat treat process. Yes, The army recognized an issue with the heat treats and implemented a double heat treat some time around serial number 750,000 to 800,000, but if you really study the investigation into the failed receivers and the sample lots tested, there were castastrophic failures even at serial 808,792 It appears to be a great rifle, but I just want to bring up the endless debate on if it is or is not safe to shoot. All Springfields made after this change are commonly called “high number” rifles. Those Springfields made before this change are commonly called “low-number” rifles. This was commenced at Springfield Armory at approximately serial number 800,000 and at Rock Island Arsenal at exactly serial number 285,507. To solve this problem, the Ordnance Department commenced double heat treatment of receivers and bolts. It proved impossible to determine, without destructive testing, which receivers and bolts were so affected and therefore potentially dangerous. M1903 rifles made before February 1918 utilized receivers and bolts which were single heat-treated by a method that rendered some of them brittle and liable to fracture when fired, exposing the shooter to a risk of serious injury. WARNING ON “LOW-NUMBER” M1903 SPRINGFIELDS Good news! Yours is a high enough serial number so you there's no reason to not shoot it if it checks out functional. One thing to be aware of on early M1903 rifles is that some had bolts/receivers that may not have been hardened properly.

1903 springfield serial number lookup