Instead of a comparatively moderate reformer like Khrushchev or Brezhnev, hardliners maintained a Stalinist party line and were more than willing to throw the KGB at anyone who suggested anything else. This would possibly merge with a strand of Trotskyism as the Soviet Union becomes more willing to outright invade nations that won't play ball with the party line.
The Beretta 92 is generally a better handgun than most things Russia produced and would be a better service pistol than keeping the TT-33 and Nagant revolver, and given you seem to mostly fight 'security forces' who are supposed to keep the peace in occupied territory, a shotgun like the SPAS-12 makes perfect sense to issue to forces. As well, Italy (and thus presumably Italy's arms manufacturers) have been under the Soviet flag since at least 1953 if not sooner, since presumably the Soviets also occupied Italy in their victory in Europe. Hence why these "Western Guns" are seen in Soviet hands.
For much the same reason as why Tatarin and the news broadcasts are done in English, Soviet troops are taught enough English to enforce compliance with the locals. Since, imperialist conquerors or not, they have the end goal of eventually winning over the locals, having troops that can give basic instructions and orders in English to non-Russian speaking citizens of the US would be helpful. Thus the Soviet MPs who have enough of a grasp of English to work with Chris.
- Even early in the game, you can easily recruit a couple of former soviet soldiers to your side for the low, low price of some basic medical attention. Said soldiers are about as competent as your average Freedom Fighter, that is an average US Citizen whom picked up the closest gun and fought... This, combined with the fact this is the Soviet Union (which is infamous for it's We Have Reserves military policy) we are talking about, already implies low morale and conviction among the invasion/occupation forces.
- Later on, former Soviet soldiers go from a rarity to being somewhat common among the ranks of the Freedom Fighters. While it says a lot about the Freedom Fighters that they are so willing to accept hapless enemy conscripts into their ranks (whether they're desperate for any help whatsoever or just idealists), the fact that 10% (give or take) of the insurgent forces are former Soviet personnel says a lot about attrition rates, as these 10% of the insurrection are only the 1) deserters that 2) were willing to switch sides instead of go into hiding and 3) survived long enough to do so, with or without help from Chris.
- Early on, Freedom Fighters use mostly the Kalashnikov rifles in standard dotation among the Soviet occupation forces. The more the games goes on, the more you see Freedom Fighters using shotguns (standard dotation among the Lieutenants) and PP-19 Bizon submachine guns (standard dotation among the Spetznaz). Considering almost all your equipment is taken from the enemy, the only plausible explanation for this improbable weapon use is that your random plucky rebels were kicking some serious ass before you recruited them to kick more ass.
- Of course, Soviet propaganda was doing it's best to demoralize the rebels, telling them their heavy fighting amounted to nothing but a mild annoyance, and they believed they were hopelessly outmatched...
- Until Chris took over the Tv station and gave his speech... And they realized they were giving the Soviet occupiers an ass whooping all along...