Welcome to SigTalk! Your trouble is likely because the take down lever wasn't fully pushed forward. You have to make sure that you push and hold it is as far forward as possible so that the slide "glides" over it.
On the SAS the slide take down pin has no lever on it. Only a coin slot.
I found a nickle coin fits the pins slot well and is big enough to hold on to.
When you are removing the slide and cleaning the pistol it is very easy to not notice that this pin gets rotated.
With no lever to see that it is out of position you will not be able to get the slide back in place.
Most of the time you will find the slot has rotated to the up and down position.
The slot in the pin needs to be running left and right aligned with the bottom of the slide.
With the slide off, you will need to push the slide lock up when you are rotating the take down pin to the horizontal position.
This is easily seen when there is a lever
A forum community dedicated to SIG Sauer Pistols and SIG Sauer Rifles owners and enthusiasts. Come join the discussion about optics, hunting, gunsmithing, styles, reviews, accessories, classifieds, and more!