From the cases that I have read in which my work has been cited in defense of those disqualifiers, it appears that:
1. A lot of domestic violence incidents that should have been prosecuted as felonies over the years were charged as misdemeanors in some states because that was sort of okay in local mores.
2. Felony charges sometimes get plea-bargained down to misdemeanors or a jury decides that it really was not that serious. I understand that judges here in Idaho sometimes encourage spouses to drop charges because "he won't be able to go hunting." My reaction is "Boohoo! Maybe he needed to think about that before punching his wife in the face. Or maybe he lacks the self-control appropriate to possession of a firearm."
However, attorney friends have related cases where someone who got a little too handsy at a fraternity party 20 years before who pleaded no contest because it was just a fine have since discovered that the Lautenberg Amendment applies even to old convictions for which the defendant could not have forseen such serious consequences.
Also, a lot of actions that are really pretty minor on the violence scale: shoving your spouse out of the way, throwing a plastic cup, can be turned into a domestic violence misdemeanor.
My late brother-in-law had an argument with his mentally unstable second wife. His claim was that he was defending himself from a violent attack. (While I never saw him in a particularly favorable light, she was crazy and I found his claim credible, or at least plausible.) Police of course, hauled him away and charged him. There is a strong bias towards the idea that domestic violence is almost always male on female.
The case on which I am working involves someone with a misdemeanor domestic violence conviction. While this is only a ten year disqualifier under state law, it is lifetime under federal law. Reading the account to which he pleaded nolo contendre does not cover him with glory nor does it make him sound particularly violent or scary.
So I have been researching battery laws. They have a far more interesting history than I expected. Under English law at the time of the Revolution and in many of the colonies, battery was usually dealt with by civil suit not criminal prosecutions because the legal definition of battery involved any unwanted touching, even of your clothes. Violence or injury were not required.
I spent some time gathering sentences for battery from the colonial period. To my surprise, lots of cases were visible online.
For 1866, just before the 14th Amendment incorporated the Second Amendment against the states, I found often very complete records of sentences by state or city.
These sentences were fascinating. Sentences were never as severe as the state law allowed. In a number of cases, the sentence was a fine of six cents! Even in 1866, this was not even a slap on the wrist, more like a tap on the wrist.
And again, battery was often resolved through civil suits. Battery by itself was not considered terribly serious, unlike extramarital sex or running a gaming house.
Domestic violence had theoretically severe penalties under Massachusetts and Plymouth Colony laws. There were very few cases. One case had the husband put in the stocks.
It does not appear that domestic violence was ignored. One of the Plymouth cases came to the attention of the authorities because the neighbors were concerned for the husband's life. This was resolved by a night in jail, the husband pleading for her release, her promise to mend her ways and a threat of more serious punishment if she went back to her old ways.
I think the courts need to come up with a way to distinguish relatively minor disputes (flying plastic cup, holding the door closed) from incidents that show an extraordinary level of violence or abuse. Certainly by the standards imposed by Bruen, battery was not a sufficiently severe crime in 1791 or 1868 to justify a lifetime firearms disqualifier.
Worse, this defendant's felony charge seems intended to force a guilty plea to misdemeanor parading.
