edges/cylinder segments on the inare not evenly spaced, ruining the curvature already
edges are not lining up with the perpendicular cylinder edges
Depending what this mesh is used for (offline rendering? game art? highpoly/sub-d model to be baked down?), just start with a really low amount of segments. This will ensure it's much easier to manage merging the two together, and easier to control the shading.
In essence, this issue you have is just due to way too many erratic segments, which are then smashed together.
Preparing the two meshes to be welded/booleaned/merged together, ensuring the segments are low and manageable, and line up
Booleaned together, no stray vertices, edges are straight and preserve the cylinders curvature
Added additional holding edges/support loops for sub-division.
More high poly work has been done since last time.
Added scope and mount. Added classic iron sight, front handguard and buttstock. Added a short version, bustock, handguard with suppressor and a new magazine. Added new grip and flashlight attachment. Added DBAL attachment.
Let me know what you think! Now I will start the low poly ) wish me good luck hehe. Thanks!
Wrapped this guy up. There are a few more things I might add at a later time, but I'm feeling pretty good about this so far. https://www.artstation.com/artwork/0nvVg4