Not a term I normally use, however, I see nothing wrong with using it when among adults that have an interest in firearms
An object, esp. a gadget or machine, regarded as providing amusement for an adult:
Same here. My SVT Lightning is a toy, and it's probably far more dangerous than any of my firearms. Some of my firearms are "true" toys, that is bought with the intention of no more than fun at the range. I have always called my guns toys and likely always will. Problem? Tough.I have to go with the "Lighten up, Francis," crowd.
My Harley was a toy. My 4x4 is a toy. My ZTR mower is a toy. When and if I find the right used Beechcraft Bonanza, it will be a toy.
One definition of "toy".
"An object, esp. a gadget or machine, regarded as providing amusement for an adult:"
Pretty much sums up all my firearms.
I think some people take some things too seriously.