I went to the Navy's website to find the original article and this is what it had to say:

"They picked up the bullet off of the floor in the back of the car. Well, I
decided that this is something, you know, the third bullet has never been decided
about ever, apparently. So what I did was I decided there was only person still alive
from the original Warren Commission. I went through the entire Warren
Commission book. I've got the whole report of the Warren Commission as a matter
of fact. I went through the whole thing and there was nothing in it.

Now, at that particular time nobody said anything about this. And I know
what we did. We brought that in, I mean Chief Martinell and Chief Mills went to the
White House, went to the Queen Mary, got the stuff off of the floor in the back seat,
brought it back out to us and we gave that to Commander Humes at the time.

I don't know what happened to it, so I decided that what I would do is I
would write to President Ford, which I did. I wrote to President Ford and asked
him, this was this past summer. I asked him about, you know, did he know anything
about this particular bullet that was given to the autopsy surgeons and he wrote me

back a very nice letter, said, "No, he didn't know anything about it, had not heard
anything about it ever." Well, at that point then I began to look around for other
issues and I found that Senator Arlen Specter had been an Assistant Counsel to the
Warren Commission. "

Young wasn't specific about who the "They" were in the opening sentence but it only makes sense that "They" were the Secret Service. The Navy NCOs were sent to retrieve the bone fragments, not search the limo. The fragments apparently were place in and envelope which was later given to Humes.  Young might have simply assumed the envelope also contained the bullet found on the floor of the limo. Nothing I have read indicates Young actually saw a bullet. As I observed earlier that it would make no sense that the Secret Service would turn over a whole bullet to the Navy NCOs while retaining the fragmented bullet. The only thing that makes sense is that the bullet Young had heard about and the fragmented bullet the Secret Service found were one and the same and that Young simply assumed the bullet was in the envelope. Misunderstandings such as this are the source for so many of the myths surrounding the JFKA.

Humes never said anything about receiving a bullet with the bone fragments and Young never said he saw a bullet so where is the evidence a bullet was received at Bethesda.

People who read the sources you are quoting are going to see how dishonestly you are portraying the evidence and how brazenly you are misrepresenting what Dr. Young said. You continue to just make up stuff, offer lame spins, dishonestly ignore key evidence, and then issue baseless, misleading conclusions about the evidence. Obviously, you still have not bothered to read the links provided in the OP, or the transcript of the 2001 interview, which is linked in two of the links.

Contrary to your falsehood, Dr. Young saw the bullet and even described what it looked like. He talked about this in the 2013 article, in his 2001 interview, and in his book What Price a Rose?. Let's read some of what you dishonestly left out:

Question: So, the bullet, again, was a copper jacketed bullet like a military bullet?

Answer: No, it was a brass jacket. . . . I don’t know, maybe it was copper, I couldn’t tell. But it was that color or brass and it was slightly bent on the end. It was not a straight bullet. In other words, it had hit something and it bent. . . . and so I called Tom Mills and I said, “Tom do you recall this situation?’ He said, "Yes I do" and he said, "You’re exactly right." He said, "We did bring that slug out from the back. . . ." (https://www.kennedysandking.com/john-f-kennedy-articles/bending-the-story-on-a-bent-bullet)

These statements are only two paragraphs below the paragraphs that you quote. Why did you omit them and then falsely claim that Dr. Young never saw the bullet?

Let's read more of what Dr. Young said that you omitted:

They went down, both Chiefs Mills and Martinell went down to the White House and then this I'm going to continue. [Quoting from What Price a Rose?] "The envelope contained three pieces of skull bone, one about three inches in diameter, another two inches in diameter and the third about one to one and a half inches in diameter. It also contained a brass slug about half a centimeter in diameter and distorted. These were found on the floor of the blood-spattered convertible. The convertible was splattered with considerable brain tissue. This also, I noted, on the back of the jacket of Agent Greer, the President's driver. (Transcript of 2001 interview, p. 51, https://whowhatwhy.org/wp-content/uploads/2017/10/Capt_James_Young_Interview.pdf)

Now, gee, why did you leave out these key statements as well?  In the interview transcript, they come just two pages before the statements you quote. So you left out key statements that come two pages before and a few paragraphs after the statements you quote. Obviously, you were trying to mislead readers.

You want people to believe your lie that Young never saw the bullet, so you omitted the statements where he made it clear that he saw the bullet.

I notice you dropped all your nonsense about the limo having to be driven to Bethesda. I also notice you failed to acknowledge your gaffe of quoting the highly condensed version of the 2013 edited by Sobocinski, obviously not realizing that it contained excerpts from only three of the 12 pages of the 2013 article.

I also notice that you simply ignored the fact that Chief Mills confirmed to Navy historian Jan Herman that he and Chief Martinell found a bullet in the limo and that Dr. Young later called him to confirm his recollection.

If you had read Milicent Cranor's article on Dr. Young's account, you would know that she debunks your theory that Dr. Young was referring to "the fragmented bullet the Secret Service found." You're talking about the two bullet fragments that the Secret Service found in the front of the limo (near the front driver's seat), whereas Mills and Martinell found a deformed whole bullet in the rear of the limo.

Even your description is dishonest. The Secret Service did not find a "fragmented bullet," but only two fragments, part of a nose and part of a tail, that constituted less than half of a bullet. And, again, those two fragments were found at the opposite end of the limo from where Mills and Martinell found the misshapen bullet.

Moreover, the two fragments found in the front of the limo were never taken to the autopsy. They were handed over to the FBI and never got anywhere near Bethesda Naval Hospital. So, clearly, those two fragments had nothing to do with the deformed whole bullet that Mills and Martinell found in the rear of the limo and that Dr. Young saw with his own eyes.

Oh, gee, Humes never admitted that he received a deformed whole bullet along with the skull fragments! Gosh and golly! What a surprise! LOL! Humes also never admitted that he determined for an absolute fact during the autopsy that the back wound had no exit point, yet we now know that he did. Humes never admitted that the first two drafts of the autopsy report said the back wound had no exit point, yet we now know that he did. Humes never admitted that he knew about the throat wound by no later than 10:30 PM at the autopsy, yet we now know that he did (partly thanks to Dr. Ebersole, the autopsy radiologist). Humes never admitted that he did two separate brain exams and excluded Finck from the first one, yet we know that he did. Humes never admitted that part of the rear head entry wound was contained in a late-arriving skull fragment, yet Dr. Boswell admitted this to the HSCA and the ARRB. Humes never admitted that he sawed open the top part of the skull, yet two autopsy witnesses, including one of the morticians, revealed that he did. Humes never explained why he said nothing about the brazenly obvious high fragment trail in the autopsy report. And on and on we could go.

Here were have a former Navy O-6, a former Navy chief, and a Navy historian confirming the finding of a misshapen bullet in the limo, along with some skull fragments, and you falsely pretend that Dr. Young's account is just a fanciful story floating around the internet.

This is yet another example of the refusal of WC apologists to acknowledge evidence that refutes their theory, no matter how credible and compelling the evidence is. Even though Young's account was vetted by a Navy historian and was deemed worthy of publication in an official Navy history, and even though Chief Mills confirmed the finding of the bullet and confirmed Young's later phone call to verify his recollection, you guys reject Young's account and offer lame excuses, demonstrably false claims, and misleading omissions to justify your rejection.

I agree. A bullet striking the radius while his right forearm was on or near his lap and deflecting up over the front seat, let alone the windshield and then striking Tague, would not only be goofy and bizarre but it wouldn’t fit the evidence.

So are you agreeing that Tague was wrong about being hit by the second shot?

Let's add one more piece of ballistic gymnastics to your already goofy theory. JBC's was struck while holding his hat in his lap. For a bullet or even a fragment of a bullet to bounce off his wrist bone and fly over the front seat would be remarkable on its own. Then to have it fly over the windshield and strike the curb near Tague would take us into the realm of the bizarre.

I agree. A bullet striking the radius while his right forearm was on or near his lap and deflecting up over the front seat, let alone the windshield and then striking Tague, would not only be goofy and bizarre but it wouldn’t fit the evidence.

    When the woman's dress neckline appeared a couple of years ago John Cotter and some other members posted that it vindicated "The much maligned Brian Doyle"...

So you were correct about an irrelevant triviality. Congratulations. You must be so proud.

it is common practice for nutters to explain these discrepancies away with lame excuses.
  they just pile up. every one. every time.

What you call excuses is nothing more than applying critical thinking. Rather than assume every discrepancy is evidence of a conspiracy we ask ourselves whether there is a more mundane, less sinister explanation available. Invariably, there is one and it is the far more likely choice than the sinister one.