Tantal vs AK74 vs AR15

According to the specs I've read the following weights have been applied to the respective rifles:

TANTAL = 8.4 pounds
AK74 = 6.7 pounds
AR15 = 8.5 pounds

The Tantal has the metal wire stock and the AK74 has the composite stock. Is that why the Tantal weighs so much more?

I would say that my fixed stock Bulgarian AK-74 feels at least as heavy as my Tantal, if not heavier. Is there a possibility that this is an apples to oranges comparison, where the Tantal weight is the weight with a (loaded?) magazine and the others have an empty magazine or have no magazine inserted? The mags, especially the loaded mags, can make quite a weight difference (and the AK-74 mags are a lot heavier/sturdier than AR-15 mags). The Tantal feels fairly light and handy to me.

This is from Wikapedia:

TANTAL
Type: Assault rifle
Place of origin: Poland
Service history:
In service 1991–2005
Used by Poland, Iraq
Production history
Designer OBR Radom
Designed 1981–1988
Manufacturer Łucznik Arms Factory
Produced 1991–1994
Number built ~25,000
Variants Kbkg wz. 1974, skbk wz. 1989 Onyks
Specifications
Weight 3.69 kg (8.14 lb)
Length 943 mm (37.1 in) stock extended / 748 mm (29.4 in) stock folded
Barrel length 432 mm (17.0 in)

----------------------------------------------------------------------
AK74
Type: Assault rifle
Place of origin: Soviet Union
Service history
In service 1974–present
Used by See Users
Wars Afghan War, various other conflicts in Asia and the Middle East
Production history
Designer Mikhail Kalashnikov
Designed 1974
Manufacturer Izhevsk Mechanical Works
Produced 1974–present
Variants AKS-74, AKS-74U, AKS-74UB, AK-74M, AK-101, AK-102, AK-103, AK-104, AK-105
Specifications
Weight AK-74: 3.03 kg (6.7 lb)
AKS-74: 2.97 kg (6.5 lb)
AKS-74U: 2.5 kg (5.5 lb)
AK-74M: 3.4 kg (7.5 lb)
Length AK-74: 943 mm (37.1 in)
AKS-74 (stock extended): 943 mm (37.1 in)
AKS-74 (stock folded): 690 mm (27.2 in)
AKS-74U (stock extended): 735 mm (28.9 in)
AKS-74U (stock folded): 490 mm (19.3 in)
AK-74M (stock extended): 943 mm (37.1 in)
AK-74M (stock folded): 700 mm (27.6 in)
Barrel length AK-74, AKS-74, AK-74M: 415 mm (16.3 in)
AKS-74U: 210 mm (8.3 in)

One of these days, when I find a cheap fish scale or something, I'll do a verified apples to apples hang weight comparison of a magless Tantal versus Bulgarian AK-74, and then with empty mags, and then loaded mags.