I got the boom mostly assembled. I have a few more things I want to solder on but that will come.
I had to cut 1/8 inch off each side of the taigen chassis to make the M4a3 hull casting from Nick Aguilar fit onto it. What a job that is. Takes a good half an hour per side. Its messy rough and tough on the face if you don't have a shield while using a dremmel cut off wheel

Here are the two small hatch tanks Im working on. The M4 and the M32B3. I have roughly fit the 3 piece tranny cover that comes in Christians M4a4 kit onto the taigen, but its not fitting well since its was made for a HL. Its too tall and long. I cut the bottom back and heated it up to reshape it a bit after grinding away lots of the material inside. Its still about 1/16 too high pushing the hull back so I am going to trim that much off the bolt bar, then reshape the bolt bar further forward on the tranny cover and sand the bolt frame braces of the 3 pieces back to shape. Should work in theory, we will see. Otherwise I will just cut down another nick tranny cover to fit like the m4 or maybe try to use the taigen, but it has a few issues preventing the hull from sitting down in place. Metal is so tough to work with.....