This would benefit from a 6 inch length and slightly larger diameter. And greater distance between baffles so less baffles Also, shouldn’t the baffles be a copper color since it’s h900 17-4?
22lr doesn't need huge volume and this thing meters around 114 so the baffles are definitely doing their job. 17-4PH is the same color as most all SS's. The straw color you're referring to is from heat during machining. If you run it hot, it will get that color (approx 350*C). Similar to Tig welding SS's. The chromium moves towards the outer layers of steel and oxidizes. Use enough coolant, during machining, and the metal won't change color. During Heat Treat, the Copper (in the 17-4) is what gives the straw tint. Even if the metal does tint, there are several ways to remove it. Mechanical (wire wheel, grinding, media blast, etc) Chemical (acid solution, etc) or Electrical (electrolysis bath).