Rpg, the gun is an older model from S&W--2004 manufacture. However, it only has approximately 4,000 rounds through it. The recoil spring was replaced around 2,000 rounds, and the gun does not see any +P ammunition. I have no intentions of selling this gun, as it is by far my favorite handgun, just want to make sure it is safe"
I doubt the crack poses a safety issue. It is primarily cosmetic.
I suspect the crack is related to machining the external extractor cut out on the slide.
I think any functional failure ( unlikely as it is) would occur in the failure (perhaps disintegration) of the extractor mechanism.
I doubt it would create a safety issue unless you needed the next round.
Since your 1911 is purely a range gun, you don't need that next round. The worst that could happen is you score badly in some competition game.
By the way, I have Colt 1911's with factory recoil springs with many thousands of rounds fired and no need for replacement.
Seems coil springs are very resilient.
Hard to imagine that 2,000 compressions would indicate a need for replacement.
After all, I've got a bunch of springs compressing and releasing compression many thousands of times in a minute in my Toyota 4 runner. Probably more compressions and releases driving to the corner than any 1911 has ever experienced.
Replacing springs after 2,000 rounds seems unnecessary unless you imagine I have to replace the springs in my 4 Runner every time I get to a stop sign.
It would be odd if such a change was necessary, or even helpful, considering I have 200,000+ miles on my 4 Runner without changing the springs that now have worked just fine over what must be many millions of compressions and releases.