Went digging into the magazine archives (boxes in the basement) and found that article. Maybe I'm shedding neurons faster than I'd thought. Some stuff got scrambled in there, but at least I found that a couple of them were still firing; just a bit out-of -proper-sequence.
The article was from much further back than I'd thought. It was published in the June 2003 issue of "Guns" as "Aguila's Innovative Rimfires" by David M. Fortier.
The picture I remembered of the fellow shooting a Winchester 1903 semiauto is there but, as Jim pointed out, I'd gotten the cartridge wrong. However, Aguila apparently was making .22 Winchester Auto cartridges at that time, which I suppose is how my gaff got started.
From the photos in the article, it would seem that Aguila made a special run of the .22 Win. Auto for Old West Scrounger. The boxes are labeled "Limited Edition Cartridges" and bear the Old West Scrounger name and their old "Hwy A-12" address. There's no mention of the run's total number, but from what I can gather it's almost certainly long gone now.
Old West Scrounger's site doesn't list them and Centurion Ordnance's (exclusive U.S. importer) aguliaammo.com site says it's "Under construction. Please try later".
Sorry again for the mix-up. Walt's post triggered the memory of seeing it mentioned that Aguila was making new ammo for the 1903 and I'd hoped to be of some help. My bad for screwing up the timeline and details.