Actually, HK’s are enough of a pain to re-barrel that whoever sold these to the gangs may end up dead.
It would be simpler to obtain working guns from South America than to re-work these.
The gangs may feel ripped off, not a wise career move for the smugglers who probably did not know they are blank firing guns.
These are mostly good for parts.
Actually, MP5s and G36s [as the Mexican FX-05 Xiuhcoatl] are manufactured in Mexico.
If they're down there, finding barrels will be easier than finding them here, at around $160 each. .
Anybody that buys a used gun, who knows anything about guns always checks the barrel and chamber.
The last thing you want to buy is a burned out or pitted barrel.
If you really want the gun and are willing to replace the barrel at least you are going to make the seller give you a low end price.
I think even a gang banger is going to look down the barrel.
Of course if you are selling to a gang banger it would be wise to be honest with them when selling them a firearm.