I don't know episode titles, but they were meeting with a band of rebel Jaffa who were led by a Jaffa named K'tano. The idea was to team up to fight the Goa'uld, including giving them Earth weapons, but SG-1 thought K'tano was acting just like the Goa'uld themselves, and Teal'c found out from Lord Yu that K'tano was actually the Goa'uld Imhotep, just rounding up a Jaffa army like any other Goa'uld would. (I suspect the episode title was "Imhotep".)
In the scene you're talking about, the Jaffa had not wanted the offered weapons because they're primitive and low-tech compared to their energy weapons (and because they run out of ammo and need to be reloaded, whereas their staff weapons apparently could stayed charged for a very very long time). So Jack called for a demonstration to convince them of the guns' power and accuracy (including, I think, having the rope which the target hung from severed by a single shot at the end), reminded the Jaffa crowd that some of them had seen how effective they were before when they had been in battle against the Tauri themselves, and then held up a gun and a staff-weapon in each hand and explained the difference between a "weapon of terror" (designed to intimidate) and a "weapon of war" (designed to kill).
"K'tano" seemed pleased by that and accepted the guns with thanks. The alliance didn't happen, though, because his power-grabbing aspirations turned SG-1 off even before they knew he was really a Goa'uld pulling a deception on everyone. After the chat with Lord Yu, Teal'c challenged Imhotep to a duel for the leadership of the group, spent most of it getting beaten up in Matrix Bullet Time because it was Goa'uld versus Jaffa, and won by acting more worn out and beaten up than he really was and thus luring overconfident Imhotep close enough to spring his trap (a sudden last-minute stabbing with a broken, splintered weapon). Imhotep died, and the followers he'd gathered became one of the original groups of Free Jaffa.
