New GP100 question

[xring]

Just today I bought a NIB blue GP100 with the 3" barrel. After dry firing it no more than 25 times a very distinct turn line has developed. It is almost fully through the bluing. None of my S&W's have done this.
Is this a Ruger trait, or is something amiss? I applied some flitz to the cylinder bolt stop, but really don't think it's made a difference.
Thanks, Randy

 

[JohnKSa]

You can polish the bolt to minimize the effect. Rugers are designed to drag the bolt.

 

[Fumbler]

My GP-100 has the drag lines. It's inherent in the Ruger design.