Lol the best thing for range and accuracy would be;
Long barrel with cylinder that's rated to the barrel
FPS matched to hop-up rubber
But again -- My team's Realsword Type 56 with the 455mm barrels and 390 FPS spring shoot only about 10-15 feet shorter than my SVD with a 690 mm barrel and 450 FPS spring.
The reason? Compression. SVD uses proprietary parts so I wasn't able to install any Airsoft Research Syndicate parts
ARS Cylinder heads combined with the ARS Piston heads is the BEST
air-seal I've come across to date.
All guns are using the proper hop-up rubber/spacers...
Almost make me wanna get a Type 56 lol