The requirements for the original design specified that the rifle weigh no more than 4.1 kg, had an effective range of 1,000 metres and a large magazine capacity.

This required an ambitious development of rifle technology but the CETME engineers, based on earlier German experiments, believed this would be possible using an unconventional projectile.

In addition, sources state that at 1,000 metres, the projectile could perforate Spanish, Russian, Italian, Czech and German helmets.

The lightness of the projectile meant it had a lower recoil impulse, which was a key objective of the engineers as it would reduce bullet dispersion during fully automatic fire.

[1] This round, chosen due to requirements of the then-interested West German Bundesgrenzschutz,[6] was dimensionally identical to 7.62×51mm NATO, but with a lighter bullet and powder charge to reduce recoil, making the fully automatic fire more controllable.

[6] Due to the tests performed by the Bundesamt für Wehrtechnik und Beschaffung [de], the ergonomy of the rifle was improved.

With feedback from Heckler & Koch, the rifle was able to fire the fully powered 7.62×51mm NATO round due to the better quality of its steel.

The 7.62×51mm CETME differed from the standard 7.62×51mm NATO round by having a lighter full-metal-jacketed, plastic-cored lead bullet and a reduced propellant charge.

The reliable functioning of roller-delayed blowback mechanisms is limited by specific ammunition and arm parameters like bullet weight, propellant charge, barrel length and amount of wear.

After a short period on the production line, it was discovered that they were weaker than the previous models and that continuous fire deformed the firearms rapidly.

Available accessories included a 1" scope mount, a plastic snap-on rifle cover, and the stock CETME magazine loading tool.

In the late 1990s Century Arms International (CAI) began offering semiautomatic only civilian versions known as the CETME Sporter, which are manufactured from assembled military surplus and US made parts.

Earlier rifles retained the wood furniture of the originals while later examples were available with Heckler & Koch style composite stocks.

The CETME delayed roller lock design has a violent extraction and ejection process that flings the empty brass far from the weapon.

The brass generally cannot be reloaded due to denting during the ejection operation, this is of no consequence when using mil-spec surplus ammunition with Berdan priming.