[High-Tech/SEALS in Vietnam] 7.62x39mm Rcl

[Icelander]

As with several intermediate deer rounds in GURPS, the Recoil of the 7.62x39mm appears to fall very close to a breakpoint between Rcl 2-3. From light sporting rifles without any recoil compensation measures, such rounds as the .30 Remington, .35 Remington, 7.62x39mm and .30-30 appear to have Rcl 3.

On the 'Muskets and Rifles Table' on HT p. 120, the 8.9 lbs. TOZ SKS-45 in 7.62x39mm is listed with Rcl 3.
What appears to be the same gun, however, is listed as the SKS-45 (K-56), 7.62x39mm on the 'Rifles Table' on p. 32 in GURPS SEALS in Vietnam as having Rcl 2. There, it weighs the same 8.9 lbs.

On the other hand, the AK-47 and AKM list the Recoil for 7.62x39mm rounds as Rcl 2. As do the RPK and the ZiD RPD light machine guns chambered for the round. Even if the SKS-45 should have Rcl 3, it's easy to see why the heavier guns in the same chamberings do not. Also, even if the AKM is lighter than the SKS-45, it has a muzzle port which makes it easier to control on full auto.

This gives rise to several questions:

1) Is the Chinese-made SKS-45 used in Vietnam a different gun from the SKS-45 listed in High-Tech?
1a) If so, does it have a muzzle port or some other modification that increases controllability in full-automatic fire?
1b) If not, does the Rcl in SEALS in Vietnam take precedence over the listed Rcl in High-Tech, as newer stats for the same weapon?
2) When statting other 7.62x39mm weapons, such as the Ruger Mini-30 or other sporting rifles in the chambering, what are good guidelines to keep in mind for at what Weight the weapon should have Rcl 2 and at what Weight it should have Rcl 3?