DIY Sealed Bore
The Cylinder Mod is a cost-saving upgrade that increases air volume. The stock brass cylinder has a hole that some say is essential for cylinder to bore matching however, real-world tests shows that upgrading to a sealed bore type is beneficial for aeg's with longer barrels. Here is a good DIY article on how to make your own sealed bore, This upgrade will be helpful especially if you are upgrading to a longer barrel (ak47 length)
Tada!
This MOD has been proven 100% effective in m4-type AEGS and long-barrel configurations.
Cheers!