Greetings:
The last time I was at the range I ran into a problem and thought I’d share my solution with you.
I was firing an auto-loading pistol that tosses brass forward, at a firing bench that had a lot of other people brass in many calibers in front of the firing line. When a cease-fire, was called I picked up any and all brass from 9mm to 45acp. It beat picking up and discarding calibers that I do not reload, only to pick up the same shell again. The cease-fire was short and it seemed the only solution at the time.
When I got home I needed a quick way to sort the brass by caliber. . I prefer to tumble only one caliber of brass, as sometimes a small case will slip into a larger case and wedge its self so tightly that both pieces must be discarded. I didn’t want to sort every piece by hand.
I had a plastic shoebox, from the dollar store and some scrap wood strips. The wood strips were about ¼ X 5/16 of an inch, and were leftover scrap from another project. I made a picket fence with 2 horizontal bars and 9 vertical pickets. I spaced the pickets apart with a 9mm shell wrapped in one turn of electrical tape. The pickets were pinned in place with a brad nail-gun.
I cut and sanded the picket fence to fit the shoebox, which had a small shelf about ½ an inch down from the lip.
To sort the brass I picked up a handful and dropped it on the picket fence /sorter grid and shook it. The 9mm fell through, the 38/357 hung on its rim on the wooden grid, the 40 and 45’s stayed on top. The large trashcan sized shells were 45’s and the smaller were 40’s. From this point it was easy to separate the various sizes to containers and repeat the sorting process.
In no time at all I had sorted a large coffee can of mixed caliber brass. After tumbling I inspected all shells for defects and head stamp and primer type.

Ivan