Members of SG1 are shown to carry a H&K MP5 as their primary weapon in the earlier series/seasons. At some point, they replace that with an FN P-90.

Was it ever explained why?

  • 2
    Out of universe it was almost certainly down to the availability of blank-firing rounds. I've also seen rumours that the show was getting product-placement money from H&K for the first few seasons but that's totally unconfirmed.
    – Valorum
    Commented Sep 26, 2014 at 9:24
  • 6
    Plus the empty rounds drop to the floor and are not spat sidewards on your co-actors glasses.
    – Einer
    Commented Sep 26, 2014 at 9:31
  • 4
    FWIW, the change happened after "The First Ones". Commented Sep 26, 2014 at 10:14
  • 3
    Mallozzi said that he liked to have an odd variety of weapons to emphasise that they're a 'special ops' team that can be trusted to choose their own guns.
    – Valorum
    Commented Sep 26, 2014 at 10:34
  • 2
    I could've sworn there was a line or two about the new equipment being issued when they change over.
    – Brian S
    Commented Sep 26, 2014 at 14:27

5 Answers 5


There is a specific episode when the characters change weapons, and it is explained why they do so. The episode where the switch was made is called The First Ones, which is season 4 episode 8. After Daniel gets kidnapped by an Unas, and after the rest of SG-1 figures out that it was an Unas who kidnapped him, they return to Stargate command. Once there, they inform General Hammond that an Unas had taken Daniel, and Jack recommended that they go back with P90s.

Turns out that they work pretty well against bad guys, so from then on the team has used them.

  • 3
    Unas being particularly hard to kill and all.
    – user15742
    Commented Sep 27, 2014 at 15:11
  • 2
    Not really an explanation, though. The exact dialogue is: "O'NEILL : Recommend units one and two, P-90's. I also recommend we take off right now, Sir."
    – dg99
    Commented Sep 28, 2014 at 4:44

That is obvious.

FN P-90 has more stopping power and a higher rate of fire than a H&K MP5! It is also marginally lighter and has a higher effective range. If you are Special Ops what do you go for??

Portability, Stopping power, rate of fire. You don't want to get too encumbered, you want the things you are shooting to stay dead and you want to put so much hurt downrange that enemies get suppressed when you fire at them.

A simple Wiki search will tell you all you need to know about these 2 guns.

Never explained why, although if they had any kind of advisor he/she would tell to switch. Especially if the Director/producer is looking for a more cool looking gun.

  • 5
    This is more of a real-world answer. We're after an in-universe explanation why they'd change.
    – Valorum
    Commented Sep 26, 2014 at 12:21
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    @Richard: This is also an in Universe answer, as the in Universe military is based on the real world military, if real world military would make this choice why wouldn't the in universe military? Commented Sep 26, 2014 at 12:46
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    Clearly you think that it's a superior weapon. The problem is that you've not shown me why Jack O'Neill would agree with you.
    – Valorum
    Commented Sep 26, 2014 at 12:52
  • 6
    They do give the p90s to the rebel jaffa at one point and carter teaches them to use them, and while teaching explains why they are such good guns. never any complaints about the mp5, but at least it shows they like the p90s. They also started wearing those dumb eye guards when they got the p90s >.>
    – Himarm
    Commented Sep 26, 2014 at 13:21
  • 3
    @BinaryWorrier This is as much an in-universe answer as answering the question "Is there an in-universe explanation for the different uniforms between star-trek series" with "in 1989 we had better clothing materials". Let me put it this way: If someone was asking for an out-of-universe answer, would this not be a much better fit? The answer isn't bad, since the series doesn't seem to provide justification and this seems to be as close to an explanation as you can get. But it's still incomplete - it does not specify whether an in-universe explanation exists or not.
    – mechalynx
    Commented Sep 26, 2014 at 16:15

No, a rationale for the change in weaponry is not discussed at any point in the script of any episode. (Hard to provide a reference for a counterfactual, so you'll have to trust my having watched each episode too many times.)

As mentioned above, Jack does discuss the benefits of projectile weapons (specifically the P90) over staff weapons when giving them to the rebel Jaffa, but there's never a discussion of P90 vs. other Earth weapons.

On a side note, over the years SG1 hired several combat veterans as consultants specifically to improve the realism of their combat scenes. That's why SG teams are always seen firing in short bursts (even with full-auto weapons) and why the actors often yell to each other during pauses in firefights (because in reality they'd be deaf). Notice how when they're in Zat/staff fights, they don't yell to each other very much.

  • 2
    "SG teams are always seen firing in short bursts" Actually it always distressed me that they didn't do this very much Commented Sep 27, 2014 at 14:46

The hypothetical in-universe explanations that I've heard which seem to hold water are

1) The unavailability of their older weapons owing to the start of the Iraq/Afghanistan wars. (It's well established in universe that those wars were taking place)

2) The older weapons were simply being phased out of service for newer ones, and as maintenence parts were harder to find, well, that sort of thing does happen in militaries fairly regularly.

That said, neither of these answers are canon.


There was also a point in which the base had upgraded all the monitors on base from CRTs to LCDs, and yet there was no in-universe explanation for that either.

Hardware upgrades happen on a regular basis because they happen in the real world too. And they happen for the same reason: newer, better equipment comes along. It's not a particularly interesting thing to spend time on, and it doesn't add to the story.

  • This doesn't really answer the question. In this instance, there's no obvious reason for the change from a newer/better argument.
    – Valorum
    Commented Jul 10, 2015 at 23:39

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