Willing to take a few bite marks? Can't read minds?
Willing to take permanent tendon or ligament damage?
Willing to take upwards of 100 stitches?
Willing to lose muscle tissue?
Willing to lose use of the limb?
Methinks Jacobie hasn't read much on large dog breed attacks. Either that, or he's much braver than I am.
Note: Broke up a fight between a Great Pyrenee and a Pit bull yesterday at the park. I love dogs, and am not unduly afraid of large breeds. Violently aggressive large breeds inspire what I consider a reasonable and necessary amount of fear. In the market for a Vizsla at the moment, and have owned a shepherd/rott mix and a catahoula, and taken care of dogs ranging from labs to American bulldogs. I have a lot of experience at breaking up fights at my local dogpark, too.
However, the injuries I described above have all been suffered in recent history by victims of serious dog maulings. I didn't bother to list fatalities, but although they are rare, they happen, too.
So how much injury are you willing to suffer before a firearm comes into play, exactly?
On reading of minds, as several posters have already noted, it's all in the body language. Some breeds are more vocal than others, so growling isn't necessarily a valid cue, but it isn't hard to read body language if you know dogs in general. The OP indicated he has plenty of dog experience, so I'll assume he can read the cues.
In the OP's case, assuming he is familiar with dogs, and the dogs were threatening, and assuming he had a safe backstop for his warning shots, I have no problem with his actions. The local police may cite him for discharging a firearm within city limits (I know somebody who was hit with a misdemeanor charge in the Orlando area for dispatching a rattlesnake in his yard with an M-1 carbine many years ago), but then again they may not.
One thing is sure, the dogs didn't harm the OP or his group, and neither the dogs nor any third parties were actually harmed.