Since it looks like this subject is going to have a life of it's own" again, I guess I might as well enter my opinion, which is worth exactly what you're paying for it!
I stand somewhere in the middle between the two of extremes of "Use a LN M1903 and you'll die" and "LN M1903s are perfectly safe". I do agree that probably most low numbered M1903s are safe to use. However, I have made the decision to not use LN M1903s because I don't enjoy taking chances, even small (avoidable) ones.
As was stated above, they did shut down production in the middle of a war to correct the problem, so that's telling me it wasn't a small one. Low numbered receivers continued to be scrapped on the arsenal level between 1927 and 1941. Yes, I know they were used extensively in World War II and by the Marines. However, the term "war emergency" comes up. Taking a M1903 to the range for an afternoon, hardly qualifies as a "war emergency". Again, it is a risk, however small, that can be avoided. Yes, if an intruder was in my house and I needed a bolt-action rifle, I wouldn't dig through my '03s until I got to a high numbered one, I'd grab the FIRST one ... but again, the term "emergency" comes up in that situation.
I agree that there are ways that having a receiver burst can be lessened, but, again, when going to the range, it isn't that hard to grab #1205868, rather than #230477. (Both are serial numbered M1903s I own).
Obviously, this is a choice that any of us who own low numbered M1903s would make and I wouldn't even START to tell people what they should or shouldn't do.
(P.S. I will admit, the last November 11, when I wanted to honor my WWI ancestors, I DID take RIA 272,505 to the range and fire off 11 shots!)