The R-6500 section from my old rec.guns faq
The next model out was the Sporter II (Cat# R-6500). When
this gun first appeared in 1985 it had many of the old Sporter
1 (SP1) features. New to this model were these M-16A2
features.
Flash hider with closed bottom
Barrel with 1in7" twist, heavy from front sight base forward,
same as SP-1 under handguards
Front sight post squared
Round handguards
Longer, stronger buttstock
Delta ring; A2 style, angled
finger-grooved pistol grip
Early guns had no forward assist, when first added it used the
old M16A1 teardrop style plunger. Later a large round style
plunger was used. I have also observed at least one of this
model with the cartridge defector hump behind the
ejection port , this rifle was also one of the export guns made
up in .222REM instead of .223REM.
Later R-6500 with teardrop FA.