03-21-2014, 03:12 PM
The marks often come from dragging against the barrel extension teeth, and are normal for rack-grade guns that use the cheapest extensions as possible.
Blown-up images magnify the features to a point that most people are not used to seeing, and it's easy to jump to conclusions.
I like to polish my barrel extension feed ramps and take edges off where the projectile, neck, and shoulder interact with the extension.
You will also get pretty bad scratches from extracting the cartridge, as mentioned by StoneTower, where the ejector is forcing the cartridge to bind against the inside of the barrel extension teeth.
Can we see pics of your barrel extension?
Blown-up images magnify the features to a point that most people are not used to seeing, and it's easy to jump to conclusions.
I like to polish my barrel extension feed ramps and take edges off where the projectile, neck, and shoulder interact with the extension.
You will also get pretty bad scratches from extracting the cartridge, as mentioned by StoneTower, where the ejector is forcing the cartridge to bind against the inside of the barrel extension teeth.
Can we see pics of your barrel extension?