Mike,
there are at least 4 modern US sets available from Preiser.
72500 - Modern US Infantry
72519 - Modern US Infantry in action
72524 - Tank Crew US Army 2000
72530 - Tank Crew US Army 2000 (Set 2)
http://www.plasticsoldierreview.com/ManufacturerList.aspx?id=22PSRs Preiser index can be a bit confusing because they list many true H0 sets (1/87) as well.
One of the misconstrued sources for the mythical "
100 sets of WWII Germans" in the
Book of 1/72 Legends... .
One more is still announced, although it could take several years until its release.
72544 - "US-Army modern, Fahrer & Aufsitzer", modern US Drivers & Seated Soldiers
https://hobby-guensel.de/PREISER-72544-US-Army-moderne-Fahrer-und-Aufsitzer-Massstab-1-72Although the sets are all labelled "modern", some are more appropiate for late Cold War and some are better for early 2000's Afghanistan/Iraq.
Regarding modern russian weapons, the latest ModelCollect/Caesar set could be interisting for you.
http://www.plasticsoldierreview.com/ShowFeature.aspx?id=106The figures are available seperately as well afaik.
As mentioned before, in general I also would love to have such hard plastic sets you're referring to.
Till then we can take suitable surplus weapons from the mentioned figure sets and use the customary alternatives in resin & metal.
ACE 7228 - Modern Soviet/Russian weapons (etched metal)
Lancer 72025 - Russian hand weapons, AK family (all resin)
Lancer 72026 - Russian weapons, MG & Grenade Launchers
OKB Grigorov W72001 - M79 Grenade Launchers (all resin)
OKB Grigorov W72002 - RPG-7 Rocket Launchers
OKB Grigorov W72003 - RPG-7 rocket-propelled Grenades
OKB Grigorov W72004 - M16A1 Assault Rifles
OKB Grigorov W72005 - M82A1M Barret Sniper Rifles
... some "modern" (well, at least post WWII) examples.
Hope this helps a bit?