In vanilla FO3 assault rifles are meh, they spray a bit too much for what they're supposed to be and the G3 is a piece of rubbish not worth using. So here we have a simple ESP which does the following:

For the mod-phobic you don't need a mod manger just activate it the way you did your DLC. Unpack into fallout3/data and tick under "data files" in the launcher.

"Assault Rifle" (G3/CETME/HK33/whatever)
Damage 9->11 (on par with Chinese AR)
Crit Damage to 9 (one less than Chinese)
Min spread 1.5 ->0.75
Max spread 4->3
Mag size 24->20 (has to be a downside)

Chinese Assault Rifle
Health 400->500
Spread 4->3.75
Min spread 1.5->1.1
ROF 8->8.5 (increase of 1/16)
Mag size 24->30

Xuanlong
Health 400->550
Spread 4->4
Min Spread 1.5->1
ROF 8->8.5
Mag size 36->40