Well over the Last 2 yrs i've had so many people ask me if it's possible to shroud the 400 and the answer has always been no, well up till now anyways. It took me a while but got there in the end, just need to put the Transfer tube in from Cylinder to Barrel when it arrives in the post. Done this one in Blue to make it stand out.
I presume you have a commercial interest in not showing pics of the internal mods so I wont push it. It would have been interesting to see how you tackled the considerable increase in distance between bolt and hammer but I assume its just a longer link screw. Is the purple bit 3D printed or metal?