A few points:
A typical Presto canner in the 15"x15"x15" size has nearly 1,000 square inches of surface area. At 10-15 psi there is tremendous potential inside. Having seen the results... Another common mistake is trying to speed cooling with snow or ice, don't.
There is a chemical reaction involved in browning meat. It has to be hot, much hotter than boiling. That requires a relatively dry frying pan and lots of small batches. Crowd the pan and you end up with boiled meat. That adds nothing. Giving anyone unable to taste difference the benefit of the doubt they likely did not truly sear the meat. Browning bulk ground meat is slower, requires care to keep the liquid level down in the pan, and the extra surface area takes more messing around.
The head (extra space) in the jar is what builds vacuum and seals the jar. Cans do not require head because they are mechanically sealed before cooking.
I canned several bears this spring in retort bags. For meat there is no comparison between jars and retort bags.
