(adsbygoogle = window.adsbygoogle || []).push({}); Series of gun types within the game high damage, low damage etc.
All share the same damage models.

However also a type of gun called a bullpup, this is given a couple cool bonuses.

Faster movement when ADS
Less recoil when moving
Less spread when moving
And better hipspread

Downside is they are worse when not moving compared to other guns within the same class.

The following weapons are bullpups within the game. Believe that all of them.

ARs:
L85
AUG
F2000
SAR 21 - Does not gain any bonus, but it a bullpup by design.
FAMAS
QBZ 95-1

Carbines:
A-91
SG553
MTAR-21
Type 95B-1

LMG:
QBB-95-1

DMR:
RFB
QBU-88

Sniper rifles:
338 recon

Is a bug with some which removing the speed bonus if you add a sight to the gun. This is due to be fixed I believe.