I may have missed something but in The Walking Dead Season 7, Episode 4 - Service The Saviours came to Alexandria and took ALL of the guns, After Negan remembered that Rick and his group had "an assload of guns.
They went through the invoice, and when they realised that they were missing 2 guns Olivia was threatened, until the guns were found in Spencer's house.
Rick even handed over the rifle that Michonne was practicing with and attempting to hide.
From then on in the Alexandrians are not shown to have any guns except for:
Rick when Daryl gives him his Python back
Rosita with the gun she got in Episode 4 with the bullet made by Eugene
The focus of Season 7, Episode 12 - Say Yes was Rick and Michonne trying to find guns to fulfil their bargain to Jadis.
How then, at the end of this episode
Rosita leaves Alexandria and turns up at the Hilltop, in what appears to be a confrontation with Sasha. However Rosita tells Sasha how the group aren't ready to fight Negan yet and wants Sasha's help in killing him. She then opens a bag and pulls out a scoped rifle.
This looks like the rifle that Sasha has used throughout the series. Sasha even give a bit of a look that made me think she was being reunited with her old gun. How did this rifle miss being taken by the Saviours and why was no mention made of it till now.
Especially as Rosita went through the hassle of getting a bullet made.
Or is it just that Rosita stole one of the guns that Rick and Michonne found, that looks like the one Sasha used to have and it just hasn't been noticed yet?