Any time you heat metal up and put it in a preshaped mold you are doing investment casting, which dates back to the early bronze age, when it was known as "Lost Wax Casting."
MIM, "Sintered metal" etc. all are just fancy names to avoid the fact you are investment casting.
Colt began this semantical nonsense back when they began using "sintered metal" hammers and triggers. They would heat metal shavings up and put em in a mold.
Kimber has added to the semantics with MIM....Sintered metal, metal injection moulding, no matter what they call it, its just investement casting.
A rose, as Shakespear once said, would smell just as sweet by any other name. Supposedly the same logic states the reverse would be just as true for canine droppings. It would smell just as bad no matter what you called it.
Ruger can get away with investment casting for two major reasons.
Number one, their guns were DESIGNED to be made that way. Thats why their parts are generally LARGER, which is the second reason.
If you design a part to be cast, and you make it oversize in the first place it can equal the strenght of a forged part.
The problem is when you start taking guns DESIGNED to have smaller, forged steel parts and replace them with cheap castings, IC, MIM SM or whatever you want to call it.
Ruger and Dan Wesson make some strong guns. But nobody accuses them of being svelte.