First, this is an idea I found on another forum and I'm just tinkering with it.
OK, I started with a vacuum cleaner belt (Kirby?), cut.
The other gentleman specified a .44 wad cutter punch, which I immediately saw as too expensive to buy just for this.
I had a cheapo set of punches that included a 7/16" (.437") and figured that was close enough.
At the spacing I chose, the belt was long enough for 11 holes. It looks like it might have been possible to squeeze in 12.
The holes are a good fit for .44's, but I tried .45 Colt and I believe those will work as well.
I plan on experimenting with glueing a second, solid layer on the back to provide more rigidity.
That should work fine as long as my glue is kept away from the holes, so the cartridges will still insert easily from the front.
I welcome all suggestions and improvements.
Mike