[dop_lex]

Disclaimer: I have not bought all of these items but this is a possible build for this gun. Feel free to correct me if these parts do not go together. I am not responsible for wrong assumptions.

Barrel - This fits on the stock hop up:
Angel Custom G2 SUS304 Stainless Steel 6.01mm Sniper Rifle Tightbore Inner Barrel (486mm / Snowwolf M24), Accessories & Parts, Sniper Rifle Parts, Barrels - Evike.com Airsoft Superstore
Internal piston -
Airsoft Sniper Rifle Upgrade Kit for APS / Type96 / Shadow Op / MB01 MB05 / Snowwolf M99 / M24 & Comp. Sniper Rifles, Accessories & Parts, Internal Parts, Springs, Sniper Rifle Springs - Evike.com Airsoft Superstore
Bucking & Nub (may need customization) -
King Arms H.Q.A. Airsoft AEG Hopup Bucking - 80 Degree / Hard Type, Accessories & Parts, Internal Parts, Hop-Up, *Hop-Up Bucking - Evike.com Airsoft Superstore
Angel Custom CNC "H-Hop" Hopup Spacer For All Airsoft AEG (Set of 2 / Black & Clear), Accessories & Parts, Internal Parts, Hop-Up, *Hop-Up Bucking - Evike.com Airsoft Superstore
Advanced Hop up (over Seas) -
X-FIRE PDI official distributor
APS Hop-Up Chamber (M24/APS-2)

I recommend getting the evike.com together and use the coupon code to get 20% off
Also if someone can correct me if I'm wrong I will update my post