Mk25 recoil spring possible rust????

[USMC169]

So I got a new Mk25 a few months ago and I'm finally able to take it out. I went to clean all the grease from the factory and when I took off the slide I noticed the recoil spring is multicolored. So is this rust or is this normal??? What say you Calguns.

[briguy64]

Normal, my 226 has the same. I think it is just some sort of factory paint that is left on there during production

[IVth Horseman]

I believe the paint indicates the springs strength. When you replace the spring, red would be factory standard.

[thai562]

Sig's springs are color coded to the caliber of the pistol.

[P5Ret]

Normal Sig color codes their recoil springs.

[sully007]

Everything normal, nothing to see here.

[nikki#2]

That's not rust... This is rust:

[USMC169]

Thanks everyone. Just checking cause this is my first sig. I've seen that post and that was one of the springs I checked.