INFO from:
http://www.world.guns.ru/assault/as60-e.htm
data for CETME mod. B / Mod. 58 rifle
Caliber: 7.62x51 mm reduced power load; also 7.62x51mm NATO
Action: delayed blowback
Overall length: 1015 mm
Barrel length:
450 mm (450 millimeter = 17.7165354 inch)
Weight: 4.4 kg
Rate of fire: 550 - 600 rounds per minute
Magazine capacity: 20 or 30 rounds
INFO from:
http://www.cruffler.com/review-july-00.html
Type: Self loading rifle
System of Operation: Delayed Blowback
Caliber: 7.62mm NATO
Capacity: 20 round detachable box magazine
Sights, front: Elevation adjustable post
Sights, rear: Four position elevation flip aperture
Length: 40.75"
Barrel length:
19.75"
Weight: 9.7 lbs
The 17.7" barrel quote is the same as for the G3, and is the rifled portion of the barrel only, and does not include the length of the flash suppressor or muzzle device.
I believe that the 19.75" barrel quote on the cruffler site includes the length of the permanently attached muzzle brake that used to be on post-ban CETMEs. The most recent CETMEs from Century do not come with the muzzle brake, so you are back to the original 17 inch length of the barrel.
Hope this helps.