>>64174878
So a G3 and CETME locking mechanism is different, the G3 is a plunger and the CETME locks onto a tab. On top of that the CETME C and CETME L have different size locking tabs and the CETME L is smaller so you can't directly connect a CETME L bayonet to a CETME C despite the muzzle device being compatible on all three rifles.
There's a second issue (at least on my example, a Century built G3); The CETME's front plug has a cleaning kit and the cocking tube does not stick as far out meaning that the you'd have to remove the cleaning kit tube. There's another difference where the G3 has one locking pin for the front plug and the CETME has two holes.
I think it's possible with modifications to a CETME front plug and your triple frame by
1) removing material from the lug so it fits in the bayonet
2) removing the cleaning kit tube
3) adding a hole opposite of the existing retaining pin hole on your triple frame
3a) You'll also want to egg the existing hole like on the G3 so you can depress one pin, rotate the pug and depress the 2nd pin for removal.
t. has a CETME C, G3 and CETME L bayonet in front of me.