Have this checked out. These pre 1920 receivers were made under primitive process controls and the metallurgy is highly varible, low grade, and inferior to the same stuff made today.
Take a look at the 1895 Mausers and the lug set back here:
http://dutchman.rebooty.com/1895Chile.html
Receiver set back is a very serious and dangerous problem.
There are a number of National Ordnance M1903A3 on the market, many were soft, I had one, and mine experienced lug set back, but I stopped shooting it before anything bad happened.
This guy had one blow up on him due to the receiver stretching.
http://forum.pafoa.org/general-2/53553-ouch-i-hurt-my-gun-broke.html
The owner reported he had only 76 rounds of factory ammunition before the lug set back caused a cartridge rupture.
Look at the damage and understand you don't want this to happen to you.
This young man was very lucky he did not lose an eyeball. I expect he had more facial damage than what you see in these poor camera phone pictures.
And he did nothing that was his fault. He simply fired enough factory ammunition until the National Ordnance receiver failed.
This is another account of a National Ordnance which blew up in the gentleman’s face.
http://www.milsurps.com/showthread.php?t=8778&highlight=national+ordnance
Later he commented on his injuries
i was the guy who had the National Ordnance 03A3 blow up in my face. I like you am still pushing people away from those ticking time bombs they call rifles. I had one surgery after I last conversed with you. Had to have a tooth removed, piece of brass was blown into my nerve and the sun still burns my eyes from absorbing heat.
http://www.jouster.com/forums/showthread.php?t=2893