You know that quite a few weapons in real life that are used in militaries today are things that were created back in the 80s and beyond, right? Or at least merely updated from the original version of that weapon. Like the AK-47 turning into the AKM, then the AK-108, but still the same frame and workings. The Colt M1911, while not the main US military sidearm anymore, is still used by soldiers and that was made in, as it says, 1911, over 100 years ago. The Browning M2 .50 caliber heavy machine gun was also produced back in the 1920s.
Basically, if it ain't broke, don't try to fix it.
In terms of JUST the multiplayer, non-Scorestreak weapons (people can feel free to correct me as I'm no weapon expert):
MTAR - Just a rename of the TAR-21, which was also in MW2, and real.
Type 25 - While there's no actual "Type 25" in real life, it was actually originally going to be the Type 95 from MW3, which is the QBZ/"Type"-95 in real life (Chinese).
SWAT-556 - Based on the SIG SG 550
FAL OSW - Real
M27 - Real
SCAR-H - Real
SMR - Based on the Saritch 308, a Russian assault rifle in development.
M8A1 - Based on the XM8 assault rifle that was cancelled
AN-94 - Real
MP7 - Real
PDW-57 - No actual weapon called that, but it's usually compared to the P90.
Vector K10 - Real
MSMC - Real
Chicom CQB - Based on the JS 9mm
Skorpion EVO - Real
Light Machine Guns:
MK48 - Real
QBB LSW - Real
LSAT - Real
HAMR - Based on the HAMR IAR (Heat Adapted Modular Rifle) (International Automatic Rifle; competition), from the SCAR family. Never made it to production.
Remington 870 MCS - Real. Was the Stakeout in Black Ops I.
S (Saiga) 12 - Real
KSG - Real
M1216 - Real
SVU-AS - Not by that particular naming, but it's based on the Dragunov SVU (Russian)
DSR-50 - Real.
Ballista - Real
XPR-50 - Not real.
Five-Seven - Real.
Tac-45 - Not by that name, but based on the FN FNP
B23R - Not by that name, but based on the Beretta B93R
Executioner - Not by that name, but based on the Taurus Judge revolver.
KAP-40 - Not by that name, but based on the KRISS KARD.
SMAW - Real
FHJ-18 AA - Not by that name, but just a modernized Stinger Missile Launcher.
RPG - Modernized-looking RPG-7.
A-91 is a carbine.
Also the Type 25 and QBB-LSW are not real life guns and are the futuristic versions of the Type-95 (1995). The 25 stands for 2025 which is when this game takes place. The QBB-LSW in this game clearly uses the Type-25 platform and not the Type-95 platform, so it isn't a real weapon either.
One dead give away is the guns differing appearence to the type-95, although they are both bullpups.
Just some (way too many) corrections :3
The MTAR is a smaller version of the TAVOR or TAR 21
SWAT 556 is the sig 556 only the civilian version (i believe) this is noticed due to the size of the hand guard
the PDW 57 is a mix of FN P90 and MagPul PDW prototype (not sure if they released it)
the Chicom is a "throw-together" of a bunch of guns like the MagPul FPG (FMG 9 not original name) handle and a bunch of others
QBB LSW does not exist however resembles the QBB 95-1
HAMR is literally just a decked out Scar H (heavy) lol even the drum mag is a standard today
SVU-AS is a real weapon
DSR-50 is actually just DSR-1
TAC-45 i a very slightly modified version of the FN-45
B23R dude, seriously? im pretty sure its damn near impossible to not see the resemblance to a tactical m1911 from today? even the slide exists as well as the hammer and the mag and the silencer (osprey somthing) and the sights. the only resemblance to the M93R is the burst shots and the corny name rip off
The Executioner and the Taurus Judge are exactly the same except for the barrel and the grip texture (stippling, easily done at home)
Kap 40 is the Kriss Kard with a MagPul look to it, also wtf? Kriss Kard, more like Piss Tard lol
Get you facts straight little boi