Crusher dust for cob?

Title says it all. Anybody have any experience using crusher dust instead of sand in a cob mix?

I'm busy building a cob oven. The building sand available around here is beach sand. They tell me it's not beach sand. It looks like beach sand. Feels like beach sand. Smells like beach sand. Makes cob like beach sand. It's beach sand.

Anyway, I found a large pile of abandoned road base (crushed rock) the other day, and decided to use it in the cob for my oven. The resulting cob is extremely hard and dust-free, which is great. The problem is that road base has too wide a variety of particle sizes. From dust particles all the way to giant, two-hands-to-carry rocks.

Yes I screened it first. But since the quarry sells the dust from the stone-crushing process as a by-product (cheap, $20ish a ton), I may as well skip the screening and just buy the dust. Right?

Anybody see any problems with this? Can fine crushed rock be used instead of sand, which is mostly crushed rock anyway, in a cob mix?

Beach sand is often no good because the grains have been rounded off with wave action, they do stick together as well and other sand.
Crusher dust may be too dusty, so be careful.
I guess if experimentation has shown it works that is good.

Thanks John. I'll report back after some more testing

My entry is meant to read' they dont stick together as well as other sands...."