There is no such thing as a Weeded Out, low number reciever. They are low number or they arn't. The <800,000 Springfields are UNSAFE. Just because one hasn't blown up yet, doesn't mean they wont.
I recommend not firing it, as mentioned, the CMP will not allow any low number Springfields to be used in their matches regardless whether one thinks the Low Numbers have been weeded out.
CPT USAR Ret
USAMU Sniper School Oct '78
Distinguished Rifle Badge 1071