Ditto on this ratio! hamburgers on the grill stay together and a burger in the fry pan will leave no fat in the pan.Just enough fat to hold the meat yet not fatty!70/30 is our go to mix when using game meat. I too use pork butt.
... Burger, 100% venison. I want my venison burger to taste like venison. Just ground up 40 lbs and put it thru the patty machine.
I'm all with you on 100% Venison for burger grind.
I don't make a lot of "burgers" with it but I find that mixing in the seasonings into the meat and then making patties allows for my 100% venison burgers to hold together no issue. I do use Minced/Dehydrated Onion rather than granulated or powder. This helps some and man I LOVE how it cooks up with grilling and smoking meat! Some pieces are crispy and crunch, some are soft and flavorful because they absorb the juices and hold it all to the meat!