Correction......Yes, the government can stop them
The government can stop gangs from including guns and ammo in their drug shipments?
The government can stop them from giving some Army sergeant a bag of cash to look the other way while they steal a truck full of armaments?
The government can stop gangs from hiring an unemployed machinist to make guns in his basement?
People who don’t care about breaking the law can’t be stopped, except by imprisonment or death.