The barrel keeps crawling forward when I tighten the tang screw.
Make sure there is clearance on any areas that might be pushing the barrel forward as the bolt is tightened. The end of the tang is one example. Also check that the tang bolt head isn't pushing on the front of the counterbore in the tang as it tightens, that can drive the barrel forward. If it is contacting the counterbore, contact us and we can get it fixed.