Promoted from the comment area.
Comment:
I’m not buying the “testing of a bullet proof vest”. A bullet can still break ribs from the force. You wouldn’t just have a dude shooting you from ten feet away. Like, maybe it was a marketing gimmick “test”.
Response (expanded):
It’s fair to say it was a marketing gimmick, but the photo is real, and so is the incident. The photo is found in the Library of Congress, labeled Sept. 13, 1923. The photo shows an employee of the Protective Garment Corp named W.H. Murphy demonstrating his company’s product. The shooter, Joseph Stehlin, also an employee of that corporation, fired two shots.

The incident was covered by a local D.C. newspaper. Murphy and Stehlin also staged a duel at point-blank range, from which they emerged unscathed. On September 13, the evening newspaper ran a photo of that encounter, which had taken place that same morning in Potomac Park, so the LOC seems to have its facts straight.

After that demonstration, Murphy allowed a uniformed policeman named O.W. Reese to fire one shot from an even shorter distance.

Sergeant Reese was not part of the staged demonstration, and used his own service revolver, so there could have been no trickery involving blanks or fake pistols. Murphy presented Reese with his own bullet, suitably flattened.
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There are other pictures available of men being shot from still shorter distances. To demonstrate his own patented vest, an inventor named Leo Krause would let people shoot him from inches away. He allegedly was shot 4,000 times without being injured. I hope he sold a lot of vests.

Not only would I not volunteer for Leo’s job, I would even have been afraid to be the shooter. I don’t know the physics of those vests, but I’d be worried about the bullet or fragments ricocheting back at me. Of course, my cowardice is legendary (I euphemistically refer to it as “prudence”).
Here is an interesting article from Atlas Obscura: “The Story Behind the Bulletproof Photo Craze. Men shot each other all the time, it seems, for publicity photos in the 1920s.”

In the 1940s, as the U.S. began developing military body armor with various “modern” materials (starting with doron), there was a lot of testing of “how much armor, and how much padding, do you need.” Material that was “bullet-proof”, backed with some sponge rubber, kapok or even layers of duck cloth, made being shot entirely painless — without the backing, the target person could experience hematoma, pain and edema, but usually without fracture. In the end, the added weight of backing material — especially since it would absorb water and sweat — was felt to be not worth the trouble. “Not being perforated” was good enough; soldiers wearing heavier armor would have other health problems, and would be less willing to wear the armor.
Wow, I stand corrected