Yeah, if using a KA this is what I would recommend buying.
https://www.kitchenaid.com/countert.../p.metal-food-grinder-attachment.ksmmga.html? Stay clear of the plastic one. Garbage.
Understand even like the old Hobart made ones these are NOT dishwasher safe being made of cast aluminum. They also are not large enough to replace a heavy duty stand alone machine such as a Lem version. Those have much larger grind chambers and can feed more meat through much faster.
It's not that any (full size) KA mixer does not have the power or durability. (Artisan Mini aside). Every one from the Classic on up to the large Commercial has MORE than enough shaft horsepower to withstand this work. The issue is the tiny little grinder attachment not the power head.
Honestly all of them have enough power to EASILY run a grinder head as large as a Lem. I honestly don't know why KA does not market a large enough grinder attachment to actually compete. But, that's on them.
So if you REALLY want to grind a lot of meat (doing it very often or in large quantity) invest in a solid stand alone machine like the Lem mentioned above.
But if you already have a good KA mixer and just want to make a few meatballs once in a while or a few burgers now and then. Invest in the attachment. It does work and work well and believe me it will NOT over tax the mixer. But it will be ssssllllllooooowwww going due to the small size.