What a Weapon Workshop Does That Ammu-Nation Cannot
A Weapon Workshop is the only place in GTA Online where a standard weapon can be converted into its Mk II version. Ammu-Nation sells the base guns and their ordinary attachments, but the Mk II conversion itself — along with the special ammunition types, high-end scopes and research parts that define these weapons — happens only at a workshop bench.
There are more of these benches around than most players realise. The classic route is a GTA$245,000 Weapon Workshop fitted inside a Mobile Operations Center, Avenger or Terrorbyte. Newer options include the Agency's Armory, a bench aboard the Kosatka, the Arena Workshop's weapon expert, and two workshops that cost nothing at all once unlocked.
Converting is not the whole system. The conversion buys you the Mk II frame; most of what makes it special, from explosive rounds to thermal scopes, is unlocked separately through Bunker Research and then fitted at the same benches.
Key Takeaways
- Mk II conversions happen only at Weapon Workshops — never at Ammu-Nation.
- The vehicle workshops (MOC, Avenger, Terrorbyte) each cost GTA$245,000 on top of the vehicle and its required property.
- 12 weapons have Mk II versions, with conversion prices from GTA$73,750 to GTA$165,375.
- Bunker Research unlocks the special ammo and attachments; each project can be fast-tracked for GTA$225,000.
- The Freakshop's workshop is free once unlocked, and the Arcade gains one at no cost during Casino Heist planning.
1. The Vehicle Workshops: MOC, Avenger and Terrorbyte
The original workshop arrived with Gunrunning in 2017, inside the Mobile Operations Center. Fitting the Weapon Workshop to the MOC costs GTA$245,000 for the standalone bench, or GTA$995,000 for the combined Weapon and Vehicle Workshop that fills two bays. The MOC itself starts at GTA$1,225,000 and requires you to own a Bunker first.
The Avenger offers the same GTA$245,000 workshop as an upgrade, but the aircraft requires a Facility before you can buy it, making it the most expensive route of the three. The Terrorbyte's workshop also costs GTA$245,000, fitted to a truck that starts at GTA$1,375,000 and requires a Nightclub to house it.
All three benches do exactly the same job. Choose between them based on which vehicle you want for other reasons — the MOC for its missions, the Terrorbyte for the Oppressor Mk II and Client Jobs — rather than for the workshop itself.
The Bunker's own role is different, and it matters. The Bunker does not convert weapons; it is where Research happens, covered in Part 4 below. That is why the MOC route begins with a Bunker purchase even though the bench sits in the trailer.
2. Property Workshops: Agency Armory, Kosatka, Arena and the Free Benches
The Agency added with The Contract includes an optional Armory, priced at GTA$720,000, which works as a full Weapon Workshop for conversions and restocking. It also sells weapons at a discount, and a few tools of the trade, like the Stun Gun and Compact EMP Launcher, are sold only there. Our Agency guide covers the property as a whole.
The Kosatka submarine carries a weapon bench on board as part of the vessel, which makes it the workshop most Cayo Perico players already own without realising it. The Arena Workshop joins the list too: hiring the Weapon Expert there adds workshop access for your Arena property.
Two benches cost nothing. The Freakshop, unlocked by working through Dax's First Dose missions in Blaine County, includes a Weapon Workshop you can use for free — the cheapest legitimate route into Mk II weapons in the game. The Arcade also gains a workshop downstairs at no cost once you choose a gunman while planning the Diamond Casino Heist.
If all you want is conversions, take a free bench and skip the vehicles entirely. The paid workshops earn their money through convenience and everything else the vehicles do.
3. The 12 Mk II Weapons and What Conversion Costs
Twelve standard weapons can be converted. The first six — Pistol, SMG, Assault Rifle, Carbine Rifle, Combat MG and Heavy Sniper — arrived with Gunrunning in 2017. Six more followed in later updates: SNS Pistol, Heavy Revolver, Pump Shotgun, Bullpup Rifle, Special Carbine and Marksman Rifle.
Conversion is a flat fee per weapon, paid once, on top of owning the base gun:
- Pistol Mk II — GTA$73,750
- SNS Pistol Mk II — GTA$79,575
- Pump Shotgun Mk II — GTA$82,500
- SMG Mk II — GTA$85,500
- Assault Rifle Mk II — GTA$98,750
- Heavy Revolver Mk II — GTA$99,000
- Bullpup Rifle Mk II — GTA$105,750
- Carbine Rifle Mk II — GTA$107,500
- Combat MG Mk II — GTA$119,000
- Special Carbine Mk II — GTA$135,000
- Marksman Rifle Mk II — GTA$149,000
- Heavy Sniper Mk II — GTA$165,375
A useful workshop perk softens the cost of the base guns: at a Weapon Workshop you can buy the standard versions of these weapons without waiting for their usual rank unlocks, so a low-rank player with a bench can start converting immediately. For which finished weapons are actually worth your money, see our ranking of the best weapons in GTA Online — this article is about the upgrade system, not the rankings.
Once a weapon is converted, you can switch it back to its standard version, and back again, at any workshop. Be aware that toggling can reset the attachments fitted to the gun, so re-check your setup after switching.
4. Bunker Research: Where the Special Ammo Comes From
A fresh Mk II weapon is only the frame. Its signature parts — the special ammunition, advanced scopes and several attachments and liveries — are unlocked by Research at your Bunker. Assign your Bunker staff to Research and projects complete over time as supplies are consumed, in a random order you do not choose.
In total there are 48 Research projects covering Mk II upgrades and weaponised vehicle modifications. If patience is not your style, any project can be fast-tracked instantly for GTA$225,000, which turns a full clear into an expensive shopping list. Our Bunker guide explains how to run the property that feeds the system.
The headline unlocks are the five special ammunition types: Incendiary, Hollow Point, Armor Piercing, Full Metal Jacket and Explosive rounds. Rockstar's own Gunrunning notes also list the era's new sights — night vision, holographic and thermal scopes — among what the Mk II system added.
Special ammo is deliberately scarce. It is carried in small amounts, it is pricey, and restocking it means a trip to a workshop bench; ordinary Mk II ammunition can be bought from the Interaction Menu like any other ammo. Plan restock stops into your sessions rather than discovering an empty magazine mid-fight.
5. A Sensible Order to Buy Everything In
Start with a free bench if you can. The Freakshop's workshop costs nothing beyond playing the First Dose missions, and it converts weapons exactly as well as a GTA$245,000 vehicle bench does. Convert the workhorses first — the Special Carbine and Combat MG cover most fights, and the Heavy Sniper becomes the game's defining long-range tool once its research lands.
Buy a Bunker next if you do not own one, because Research is the real grind of the system and it cannot be rushed cheaply. Every hour your staff spend researching while you do other things is progress you did not have to fast-track at GTA$225,000 a project.
Add a vehicle workshop last, for convenience, once the weapons justify it. The Oppressor Mk II already pushes many players towards a Terrorbyte, and its bench means one vehicle covers both flying and firearms. The order matters less than the principle: benches first, research second, convenience third.
Frequently Asked Questions
Where can I upgrade weapons to Mk II in GTA Online?
At any Weapon Workshop. The main locations are the Mobile Operations Center, Avenger and Terrorbyte with the GTA$245,000 workshop fitted, the Agency Armory, the Kosatka, the Arena Workshop with its Weapon Expert hired, the Freakshop, and the Arcade's downstairs workshop once a gunman is chosen for the Casino Heist.
Can Ammu-Nation upgrade weapons to Mk II?
No. Ammu-Nation sells the base weapons and standard attachments, but the Mk II conversion itself, and fitting research parts and special ammunition, can only be done at a Weapon Workshop.
How much does a Weapon Workshop cost?
The workshop fitted to an MOC, Avenger or Terrorbyte costs GTA$245,000, not counting the vehicle and the property it requires. The Agency Armory costs GTA$720,000. The Freakshop's workshop and the Arcade's workshop are both free once unlocked.
What is the cheapest way to get Mk II weapons?
Use the Freakshop's free Weapon Workshop, unlocked through the First Dose missions. You still pay each weapon's conversion fee, from GTA$73,750 upwards, but you skip the millions that the vehicle-based workshops cost to set up.
Which weapons can be upgraded to Mk II?
Twelve: the Pistol, SNS Pistol, Pump Shotgun, SMG, Assault Rifle, Heavy Revolver, Bullpup Rifle, Carbine Rifle, Combat MG, Special Carbine, Marksman Rifle and Heavy Sniper. Conversion prices run from GTA$73,750 for the Pistol to GTA$165,375 for the Heavy Sniper.
How do I unlock explosive rounds and other special ammo?
Through Bunker Research. Assign your Bunker staff to Research and the special ammunition types — Incendiary, Hollow Point, Armor Piercing, Full Metal Jacket and Explosive — unlock among the 48 random projects. Any project can be fast-tracked for GTA$225,000.
Where do I restock Mk II special ammo?
At a Weapon Workshop. Special ammunition can only be topped up at a bench, while ordinary Mk II ammunition can be bought through the Interaction Menu. Special ammo is carried in small quantities, so restock whenever you pass a workshop.
Can I switch a weapon back from Mk II to standard?
Yes. At any Weapon Workshop you can toggle a converted weapon between its standard and Mk II forms. Note that switching can reset the attachments fitted to the weapon, so check your setup afterwards.
Do I need a Bunker for Mk II weapons?
Not for the conversion itself — a free Freakshop bench can convert weapons without one. You do need a Bunker for Research, which is where the special ammo, advanced scopes and other defining Mk II parts come from, so most players end up buying one.
Does the Kosatka really have a Weapon Workshop?
Yes. The submarine carries a weapon bench on board, so owners can convert and manage Mk II weapons from the same vessel they use to plan the Cayo Perico Heist.
Wrapping Up
The workshop system is simpler than its price tags suggest: one bench, anywhere, does every conversion, and the Bunker quietly unlocks everything that makes Mk II weapons special. Take the free Freakshop bench, convert the few weapons you will actually use, and let Research run in the background while you play the rest of the game.
