Actually, rattling ammo is usually only a factor to the shooter, but when you really want to be silent and invisible, it can affect your confidence and comfort level. I experienced it this way.
During a search warrant for a fellow who'd killed two people in a drug deal gone bad, my partner and I were going room to room through a darkened house. (Daylight, but the owners were default on the electricity, so only dim light through curtained windows.) Tension was high, because when we crept to the doorway, the killer's sister said, "No, he's not asleep, like I said he'd be; he saw you coming, and he's hiding somewhere in here." (I voted to back out and call "Tac" [tactical team, for barricaded suspects] but the detectives who wanted us for "uniforms" [bullet-catchers] to run the warrant insisted on going ahead, and I was only a rookie on my last day of training, so we went ahead.) When we went into the second room, a semi-naked female jumped out of the bed, acting surprised. Acting seemed to be the key word, so I took my flashlight (I was a rookie, so was always prepared; I had the only flashlight in the house) and knelt to look beneath the bed. Holding my 4 inch S&W 41 mag close to my body, I lifted the dangling bedcovers with the flashlight hand. And there was a face! Inches away, staring right back at me! Adrenaline surged, I grabbed him by the hair, drug him out, and we threw him around and cuffed him. The sister runs in, begging us to not hurt him, and says, "Oh, what are you doing? That's not him! He's still in here!"
"What?? You mean we gotta do this again?" I thought... With the "under-bed" guy (also a wanted felon) under control, we continued down the hall, me in the lead. My senses were on maximum power, just like a woodland stalk. I heard an unusual sound, that I hadn't heard before. I stopped where I was, crouched, and did a slow scan, trying to find the sound. It was in front of me. It was my gun. My adrenaline had me gripping the gun so tightly that the rounds were rattling in the chambers. I'll grant you (now) that I was probably the only guy at the time who heard it. But the fact is, I wanted to be making ZERO sound at that time! Like a hunter with game in sight, I thought; "Surely he can hear my heartbeat!" Combined with stress caused by a retarded detective who kept racking rounds into (and out of!!!) his shotgun "for effect", which scared the crap out of me each time he did it, the noise from my revolver made me a little bit less confident about my "stealth", which was the only advantage in this situation where a man on his own turf was expecting people to come and take away his freedom, and possibly his life. (Texas is a REAL death penalty state!)
When "facing the elephant", you need all the confidence you can get. I want power, reliability, ease of use, and stealth. Maybe stealth is a small part of the equation for some, but it's a REAL part, so I list it as a factor. Maybe nobody else who's been in harm's way has been afraid, but I have, and I'll make allowances for that fear, and try to minimize it's effect. If a homeowner picks up a firearm to stalk a potential threat (without backup, or ballistic vests), I think they'll be feeling the same degree of nerves (possibly even more?) that I did as a rookie policeman.
The Smith was an okay gun. I don't know about clearances, or quality. It was made in the mid 1980's. After I'd put about 2,000 rounds through it, the hammer stud broke, and it had to be sent to the factory for repairs. Of the 38 Smiths issued to my academy class, 29 needed some type of work, and 19 were deemed unsafe for use without serious re-work, so I'm guessing this was not a great period for Smith and Wesson's quality control. I was a Ruger and Dan Wesson fan, so I didn't care for the Smith, but Dallas allowed us to carry a Smith or Colt, .38 or larger, and I was a big .41 fan, from silhouette shooting. The Department issued Model 64's (heavy barreled, fixed-sight stainless .38's), and I upgraded to a Model 657 at the first opportunity.
(Incidentally, I found the guy hiding in a shower stall at the far end of the house, after the detectives had given up, declaring; "Screw it, let's leave; he's not here!" He surrendered without a fight.)
My comment about the flashlight also comes from this gun. I had a Mag-light go out when I fired it in that "back-of-hand to back-of-hand" style that is sometimes taught. I attributed that to the blast coming out from between the cylinder and forcing cone. I never had that happen with a Streamlight, but then, I was always conscious to keep the "head" of the flashlight as close to my left fist as possible when shooting with it. Frankly, I think the Ayoob flashlight method is superior.
I think there were some good comments on here, and something for homeowners to learn from. The comment about "having it" really has merit, as do the comments on training. By training, you can get closer and closer to "having it", but until you experience it, you won't really know. After you experience it, you'll know, and you'll be truly confident, not simply full of bravado. Those who are hunters will understand, and can take confidence and comfort from that.
Every firearm can win a gunfight, if only the shooter can.