I'm sorry, I will not be debunked publicly. Of course, I would have been much more willing to go with this kind of debate (off the boards) had you not stated:
Geez the .223 tumbling thing was debunked 20+ years ago. Lay off the Mack Bolan novels
Perhaps you should spend a bit less time listening to the bozos at the range/gun store who tell you that a .45 will knock someone down, a .223 "tumbles", and substitute a bit more personal research shooting, reloading, and reading up on current ballistics theory.
Maybe this will help. My maternal grandfather was a gunsmith, as am I. My mother will out shoot almost any man alive with a .45, or pretty much any handgun. I grew up with guns in every corner of the house (and, I mean that very literally - my father made a good living on buying and trading guns to put extra income into the household). I've put together guy's guns who've taken them apart and brought the pieces to me in a small paper sack. You ever seen how many springs, pins and miniscule parts make up the inards of a gun? A gob!
I've done trigger work on hard pull units. I've polished the metals down using precise equipment and set the trigger to specific weights of pull. I've pulled apart guns that shouldn't be pulled apart and I know the little quirks of most of the makes out there (these little quirks are why people have a hard time with guns...As an example, there is a screw in a Smith and Wesson make that, if removed, MUST be replaced, or the gun will function improperly - it is a set screw and cannot be taken out without the need to replace it).
I don't need to talk "theory" - I have hands on experience.
Fact: When a slug travels down the barrel of a firearm (rifle and handgun - not shotgun, unless, of course, you are shooting a slug through the shotgun), the barrel expands to allow the slug space to travel. This is why, specifically, barrels need to be replaced after, normally, 1,000 or so rounds. This is not so extreme in a gun that uses mostly lead bullets, since the lead is soft and will contract, rather than force the barrel to expand. However, for most rifles, pure lead bullets are not usefull, as the lead melts from the energy (heat). This is why they use a copper jacket. Solid copper bullets, on the other hand, will burn out a barrel in 500 or less rounds, hence the need for the copper jacket surrounding the lead (just the right amount of each goes much easier on the barrel and keeps the integrity of the bullet).
Fact: If you set off the primer on a loaded shot shell, without it being in a firearm, the load will do nothing more than fizzle. No explosion, just fizzle. Most of the guys (and I'd say most = 99.99%) on the firing range will tell you that that is a completely crazy thing to suggest. Never the less, it is fact. Please note, that is specific to a shot shell, not a cartridge which will rip apart if you attempt such a thing).
Fact: The .45 long colt will knock a man down - hence the name, "The man stopper." The .45 is a big slug and it moves at a very slow rate (about 900 feet per second, depending on the powder used, the grains behind it and whether or not you are using a pressure load - no matter what, it is still a slow moving slug). The very fact that it is big and slow means that the energy will be transferred throughout it's hit area, say the chest, rather than blow through the body as would, say, a .357 round. Of course, there are contributing factors to this - the weight of the slug, whether or not you are using a full metal jacket round nose and if it is hollow point or not. Basically, if it is an ACP (semi-auto round), it may not knock the target back (again, subject to powder and bullet specifics). If, however, it is a long colt (revolver), chances are it will knock the biggest of men down on the hit. Argue that all you want, it doesn't change the fact. And, if you actually get out there and ask, say, a gun smith, he'll tell you that I'm not feeding you a line.
I worked professionally as a gun smith for several years. I finally gave up. You see, the gun industry is at the point where there aren't a whole lot of things that they can do to make guns better. As a result, they change very tiny parts on the guns and how they function. Each year, there are hundreds of tiny changes made and it gets very, very frustrating trying to keep up with these minor and questionable changes - they are NOT necessary (they don't make the gun shoot better, fire faster or do much at all to increase their reliability). Of course, the manufacturers are very quick to tell you otherwise.
In any case, give me any pre-1990 firearm and I will take it apart, including the trigger mechanism and bolt (if it has a bolt mechanism) and all internal parts and put it back together in full working condition. Moreover, give me any gun as above that YOU'VE taken apart and dropped all the parts into a box in no specific order and, given the time, I will figure out exactly
how it all goes back together and set it up in working order for you. Of course, your buddies on the firing range will probably tell you that's pretty easy.
In closing, I will address this issue:
I have my grandfathers S&W revolver which has a slight barrel bulge midway down the barrel.
It was your grandfather's gun, therefore it is old. You should note that the older guns were made with metals that are not the high quality of the metals used in firearms today. The loads that we use today are stronger, as a result of better powders. Better powders are used because the metalurgists have made steels that can take more powerful loads. Using loads on the market today, in conjunction with guns made as recently as 50 years ago, is a bad idea. The older guns simply cannot deal with the high power loads that are ordinarilly marketed today. In other words, some door knob used your grandfather old gun to shoot something that it simply could not deal with - hence the bulge in the barrel.
And that, sir, is not "theory."