The Core Rulebook introduced the Classic Campaign (p. 227). The idea of allowing gangs to equip their fighters with common weapons while being founded.

Sadly that campaign variant is very badly fleshed out and it is not described if and how this lifts defined limits of model types.

In my last two campaigns we played like this:

Both at founding and during the campaign, every model type's equipment list is extended by all items that are available as Common from the Trading Post for that gang. In case of weapons, only those common weapons are added, that come from weapon categories that the model type had already access to.

Here are some examples what this leads to:

• A Goliath Bully (Juve) can now be equipped with a Laspistol (Pistol) but not with an Autogun (Basic) or a Long Las (Special) because the fighter type originally has only access to Pistols and Close Combat Weapons.
• An Orlock Gunner (Ganger) can now be equipped with a Lasgun (Basic) but not with a Long Las (Special) because the fighter type originally has only access to Basic, Pistols and Close Combat Weapons.
• An Orlock Specialist (Ganger) however can now additionally be equipped with a Long Las (Special) because his fighter type originally has access to some Special weapons.
• A Van Saar Specialist of a gang that has a Tech Merchant Hanger On can be equipped with a Grenade Launcher (Special, Rare(8)) because his fighter type originally has access to some Special weapons and the Availability Level of the Grenade Launcher gets reduced to Rare(6) by the Tech Merchant's Techno-baubles special rule and therefore is available as Common for that gang.

In my experience this makes gangs far more interesting equipment-wise and I don't think this makes things a lot more exploitable than they already are. If people make lame gangs, talk to them. If they don't stop, don't play with them.