Don't know if this satisfies what you refer to as "SageBrush Camo" but this is what my Remington 783 .223 Rem bolt gun looks like now. As you can see from the photo, a good match for the Kryptek pattern.
Just the various Krylon Camo-specific cans of Ultra Flat Matte colors.
As I recall Krylon "Sand" Ultra Flat Matte as the base.
After masking, I wrapped elastic stretchable Halloween netting all around the firearm before doing the larger stripes of a Matte Earth Brown. (I think that was from a bunch of Rustoleum I already had?) To break-up the base color.
Then cut yourself some sponge pieces approx 1.5 x 1.5 in. Then tear away pinches of the sponge bottom surface in order to create a very randomize shape to dab with.
In larger lighter colored area... use the sponge pieces to lightly dab-in your contrasting darker colors to breakup the lighter areas, and conversely on the darker strip areas... dab into those areas with your lighter colors so the darker region are also not rigidly defined in their edges.
NOTE: Don't dab it on right after dipping it into some paint. Take that dipped sponge and first dab it a buncha times upon your palette you have the paint sprayed onto. You want it to kinda get tacky/grabby with the paint, NOT WET LOOKING! Otherwise it'll blop on way too much with those first few dabs.
As you're dabbing, make sure to rotate the sponge randomly a little bit before each dab so the pattern it has is never repeated on the gun.
I have to paint them across saw-horses. If you can hang it to paint that'd be way better. If you have to use saw-horses to lay it across like I did, make sure to put a fresh piece of masking tape across the top edges of that plastic sawhorses to give it a "clean" surface to lay against.
After each step, ya need to give it 30+ min to dry before going to the next step.
NOTE: On other rifles I tried incorporate a Gray color, wanting to mimic the color of the dead oaks. I had to mix-in just a little bit of like the Sage or the Brown into that Gray upon the palette in order to slightly darken down the "loudness" and "brightness" of the color of that Gray shade I used.
Here is a similar one I did for my .308 Win. I was running low on the sand base coat, and because the intent was for this camo to be a little more Alpine in appearance, I opted to then use whatever sage/green color it was on the barrel, then just dither it in with the lighter colors.
THEN: the Matte Clear Coat. At least 2 or 3 coats. It'll look shiny there for a substantial bit until it dries more so don't freak out.
