Stargate Through the Looking Glass and into Heaven.

[The Immortal Watch Dog]

Right that's the big question, how effective is the Jaffa's body armour? Level III? IIIa? IV?

It's armor designed primarily to stand up to energy weaponry, hence Ras honor guard could take two or three hits from a staff weapon to the chest before going down when they were armored properly. Final battle had a bunch of them rushed outside. Their helmets contain their own life support system in case they have to fight in a low to no oxygen environment. Jaffa are immune to most poisons and resistant to a lot of nerve agents so the masks are designed more for visual aid and communications.

The original SG team was equipped with the standard stuff that marines would carry at the time minus Ferrettis Ventura style minigun

They were able to wear down Jaffa armor through sustained fire, is how I've written it.

So they can be penetrated but it takes time and time and ammo wasted wearing them down = lives lost as Hammond and O’Neill both found out. Though Hammond more so due to the fact that Ra's guys were equipped for ceremonial duty and dealing with primitives.l and thus they were able to shoot at exposed areas where they were barely clothed.

A properly armored Serpent Guard who are the military backbone of the Empire would look something like this

]If the Jaffa are wearing full body suits of armour that exceeds our level IV plates, that's a nightmare scenario that pretty much requires something like the very finest tungsten-carbide AP ammo, the new NGSW, or a new family of weapons based on something like .338 Lapua necked up to .50 to handle the sabot for the steel penetrator, to defeat

For stopping power it would probably be above level IV plates. At least when going up against the Serpent Legions or the Bull guard that belong to Horus. That would be the Marine/Army equivalent.

As far as reverse engineering; they could get a head start on teching up for the war to come if they swallow their pride and make nice with the icky eugenics warriors in that season IV episode, 'The Other Side'; the Eurondans .

Well SG1s primary job would be to avoid that war via politicking. They aren't opposing all System Lords and while what they did to Ra and what they will do on Chulak will be the Goa'uld equivalent of 9-11 but once it becomes clear why they did what they did it will make both Ra and Apophis look like the aggressors and mitigate that.

Plus you're assuming this will be like the show where all System lords are enemies period
There's no reason for say Amaterasu or Ba'al to make a low key alliance with the Tau'Ri or hell even Hathor for that matter.

Since they're not interested in tearing apart the empire and ruining the only source of stability. They may wish to use The SGC against Apophis to keep their hands clean.

That really depends on how much exposure risk you want the Earth's governments to embrace.

Higher risk means quicker development. I'm betting there will be lots of secrecy. So I wouldn't expect to see much beyond prototyping for the first over the 1st 5 years, production would require probably a decade for the tools to be made to make the tools to make the tools...you get the picture.

For now, what the SGC is ordered to obtain are clean energy sources and pharmacological stuff. And some atmosphere scrubbing flowers that will show up in a few "episodes"

Weaponry and armor is going to be a secondary concern which O'Neill and Hammond both will think is mighty bizarre.

But yeah there will be a lot more civilian involvement in this.

Hell even Sam Carter is technically civilian in this timeline.

So security concerns will be paramount and maybe something I'll explore.

What I really expect to see more of in the first 2 seasons is the use of captured equipment.

Yes! That indeed will happen.

Yes, especially if Jaffa armour is hard to penetrate, stealing and using their blasters will be a priority, as will reverse engineering them.

Indeed.