Number one, you will not reach 200m, best you will do is like 140-150m, and that's if you use .69g ceramic BBs.
Gun - Novritsch SSG10
Cylinder - stock SSG10
Trigger - stock SSG10
Spring - Rapax 4J
Piston+guide - stock SSG10, maybe with piston weights
Hop chamber - AA red is what I'd use, good choice
Nub - Masada nub is good, but take a look at the SS-nub tutorial in my signature
Bucking - I'd go with either a Maple Leaf 2021 80* or 85* Autobot, or an R-hop and a flat bucking
Barrel - ESCW 5.98, EdGi, or lapped PDI, DaVinci, or Lambda 6.01
DIY stuff - one piece receiver, tape barrel spacers, cylinder sleeve, bolt handle lockup stabilizing
Gun - Novritsch SSG10
Cylinder - stock SSG10
Trigger - stock SSG10
Spring - Rapax 4J
Piston+guide - stock SSG10, maybe with piston weights
Hop chamber - AA red is what I'd use, good choice
Nub - Masada nub is good, but take a look at the SS-nub tutorial in my signature
Bucking - I'd go with either a Maple Leaf 2021 80* or 85* Autobot, or an R-hop and a flat bucking
Barrel - ESCW 5.98, EdGi, or lapped PDI, DaVinci, or Lambda 6.01
DIY stuff - one piece receiver, tape barrel spacers, cylinder sleeve, bolt handle lockup stabilizing