named Gary Kleck. His 'study' is so deeply flawed that any reputable statistician will laugh until they collapse from exhaustion when they look at it.

What Kleck did:

Using standard polling procedure he randomly dialed 5000 phone numbers and asked a series of questions that supposedly qualified the responses.

What Kleck did wrong:

At the time of his 'study' only 35% of households had guns and could possibly answer yes to the DGU question. So immediately 65% of the sample was useless. Based on the answers he got he extrapolated the results to all 300 million Americans which again only 35% could actually claim a DGU.

Second he used data that could not be corroborated through empirical measures. No police reports, no secondary witnesses, NOTHING to lend credence to the claims of the respondents.

Third he asked a highly loaded question to an audience with a bias to responding 'yes'. The possibility of getting false positives is extremely high in these situations as people who have and reallllllly like guns want to justify the importance of having them. If I wanted to get a lot of false negatives I'd ask if the respondent routinely watches porn and just accept their response without looking a their browser history.

Fourth he failed to correct for the 'telescoping effect'. This effect tends to inflate results because it uses information from outside the time window of the 'study', i.e. was the DGU in the 12 month window or was it 15 months ago?

So Kleck's 'study' wasn't really a study. It was more like a poll and a very poorly conducted poll at that.

birth certificate, Jade Helm, and the secret agenda that Democrats have for confiscating guns, the cold-dead-hands, Tea Party-leaning, Second Amendment-absolutist, NRA-pandering Gun Nuts will believe any fear-mongering lie that the Right Wing bought-and-paid-for Gun Lobby tells them.

These are the same idiots that will give Trump the nomination, and for the same reason: target-marketed fear.

link: As we suspected: NRA's Myth of Defensive Gun Use is largely just a myth

The myth of defensive gun uses as beneficial compared with the carnage caused by guns in america, is also only a small part of the overall Second Amendment Mythology (complete with 14 volume Mythology Bible set, chapters & verse).

Hear hear: But I also think these foamy-mouthed gun nuts who have to have guns everywhere they go, who have these bizarre delusions the government is going to take their guns and who buy and hoard MORE guns every time there is a notable shooting … they are the ones who buy into the Myth of the Gun hook, line, and sinker. They build their entire lives around this false belief. They threaten others who even try to discuss adding some sort of common sense to the discussion. They consider these facts to be an affront to their “rights” and it is so clear they do not give a fart about your rights.

Proponents of such putative benefits often claim that 2.5 million Americans use guns in self-defense against criminal attackers each year.

That would be Gary Quack's dgu study, which was of ~5,000 phone calls in one year asking if recipients had performed a DGU in the past year, & the whopping total of 55 said YES! I/WE DIDDED DO A DGU!

In fact, herewith is an interview Mr Kleck (my bad above) about the very issue! and note that Gary Kleck is a registered lifelong democrat (as well as a gun book seller for hire):

The interview was conducted September 14-17, 1993 by J. Neil Schulman,

SCHULMAN: I understand you asked questions having to do with just the previous one year. Is that correct?
KLECK: That's correct. We asked both for recollections about the preceding five years and for just what happened in the previous one year, the idea being that people would be able to remember more completely what had happened just in the past year.
SCHULMAN: Okay. So you've given us the definition of what a "defense" is. It has to be an actual confrontation against a human being attempting a crime? Is that correct?
KLECK: Correct.
SCHULMAN: And it excludes all police, security guards, and military personnel?
KLECK: That's correct.
KLECK: Well, as a percentage it's 1.33% of the respondents. When you extrapolate that to the general population, it works out to be 2.4 million defensive uses of guns of some kind -- not just handguns but any kind of a gun -- within that previous year, which would have been roughly from Spring of 1992 through Spring of 1993.
KLECK: We had a total of 4,978 completed interviews, that is, where we had a response on the key question of whether or not there had been a defensive gun use.
SCHULMAN: So roughly 50 people out of 5000 responded that in the last year they had had to use their firearms in an actual confrontation against a human being attempting a crime?
KLECK: Handguns, yes.
SCHULMAN: Had used a handgun. And slightly more than that had used any gun.
KLECK: Right.
SCHULMAN: So that would be maybe 55, 56 people?
KLECK: Something like that, yeah.
SCHULMAN: Okay. I can just hear critics saying that 50 or 55 people responding that they used their gun and you're projecting it out to figures of around 2 million, 2-1/2 million gun defenses. Why is that statistically valid?
KLECK: {Kleck does a fancy little tap dance here which you can read via the link below!}

KLECK: Fifty-four percent of the defensive gun uses involved somebody verbally referring to the gun.
Forty-seven percent involved the gun being pointed at the criminal.
22% involved the gun being fired.
14% involved the gun being fired at somebody, meaning it wasn't just a warning shot; the defender was trying to shoot the criminal. Whether they succeeded or not is another matter but they were trying to shoot a criminal.
And then in 8% they actually did wound or kill the offender.
SCHULMAN: In 8%, wounded or killed. You don't have it broken down beyond that?
https://www.firearmsandliberty.com/kleck.interview.html

From the above 55 dgus, Mr Quack voodooed out & got 2.5 million dgus per year in America.
Putting real numbers behind Mr Quack's percentages, remember Gary agreed with this for total DGU's: So that would be maybe 55, 56 people?

8% of 55 dgus is, um, 5. Maybe 6 if he rounds up. Wounded or killed. Maybe a few more if multiples within a dgu.
14% 0f 55 people is about 8. Eight people were shot at trying to hit them, but not wounded. (multiples?)
22% 0f 55 dgus is about 12 People(s) being shot at, not trying to shoot the criminals.
Here comes the big guns - 47% of 55 people is 27 had the dgu gun POINTED AT THEM.
About 29 criminals were VERBALLY WARNED TO GO AWAY OR A GUN WILL BE GOTTEN (some of these verbals might've escalated to other higher echelon dgu actions, such as actually being shot at, so we can't really say the half of dgus' are simply verbals, I suspect more like 30% are simply verbals).
Quack Quack.