Robert Prudhomme

No foresight?

There seem to be cops milling around the street outside the TSBD and quite a few people standing around there...not sure if I see Robert West in one of the pics - I wonder if these were taken during one of the assassination reenactments?

Also looks like the scope is strapped on - can the bolt be operated and a cartridge ejected?

Very observant, Ian! Yes, there is no foresight on the rifle, and the scope does appear to be fastened to the rifle with two wraps of tape. And no, the bolt cannot be opened and drawn back with that rear piece of tape in the way. Clearly, the scope was cabbaged onto the rifle merely for the photo session.

What is really interesting is the rifle itself. If you look closely under the stock, you can see a protruding box magazine that clearly identifies this rifle as a 6.5mm Carcano, although I do not think it is the same model as Oswald allegedly owned, that being an M91/38 short rifle. The barrel looks a bit too long to be a short rifle, although I could be wrong, and I would venture a guess it is a 6.5mm Carcano long rifle, either an M91 or an M91/41. Whatever it is, the stock has been customized and either the barrel cut short or, at the very least, the front sight removed.

The removal of the front sight is itself unusual. In 1963, scopes on hunting rifles were not that common, while it seems that everyone today owns one; to the point many rifles are made without sights, as they are unnecessary with a scope mounted. For this rifle not to have a front sight indicates someone intended to eventually mount a scope on it, although I hope they used something a bit more substantial than two wraps of tape to mount it.

So, if this rifle is a Carcano, that scope is not only poorly mounted, it is in the wrong location. As can be seen on C2766, it is necessary to mount the scope offset to the left to 1) allow the en bloc clip to be top loaded into the magazine and 2) to allow the bolt handle to stand up and be pulled back without running into the scope.

Now, if this rifle was intended to have a scope mounted on it, it tells us something else. If it was an M91/41, with standard twist rifling, cutting the barrel short would not have much effect on accuracy, and mounting a scope on this rifle would be a great idea. However, if it was an M91, with progressive twist rifling, cutting the barrel short removes the tightest part of the rifling, and this thing would be about as accurate as a slingshot. The only people who would waste a good scope by mounting it on this rifle are people who don't understand what progressive twist rifling is.

I seriously think these photos may have been taken shortly after the assassination. As I said earlier, the newest car I can find in these photos is a '63 Chevrolet Impala, and those would have been for sale in the showrooms in the fall of 1962.

Lovelady appears to be of the same height or just slightly taller than PM, and I would put this down to PM being at the very back of the 48" wide landing, and Lovelady being at the very front.

The camera is obviously lower than these two subjects, and this makes the closer subject appear taller.

Here is an interesting collection of photos shared with me by Bart Kamp.

http://www.prayer-ma...htbox[group]/1/

As best as I can tell, the rifle photos were taken from the 6th floor of the Dal-Tex Building. I looked closely at the cars in these photos and could not find anything newer than a '63 Chev Impala, meaning it is very likely these photos were taken not long after the assassination.

Notice anything unusual about the rifle?

Here is an interesting collection of photos shared with me by Bart Kamp.

http://www.prayer-man.com/sniper-position-in-daltex-building-by-shell-hershorn/#lightbox[group]/1/

As best as I can tell, the rifle photos were taken from the 6th floor of the Dal-Tex Building. I looked closely at the cars in these photos and could not find anything newer than a '63 Chev Impala, meaning it is very likely these photos were taken not long after the assassination.

Notice anything unusual about the rifle?

Look at it this way. Knowing a big cartridge in a short barrelled rifle produces a loud muzzle blast, there is simply no way a 6.5mm Carcano short rifle could have been fired from the Sniper's Nest a mere sixty feet above the heads of the onlookers in Atgens 6, 3.5 - 5.2 seconds before this photo was taken, without very obvious signs of reactions visible on these people.

I agree. Four seconds after the blast I would expect nearly everybody to either be looking around for the cause of the blast, or talking to their friends about it.

So you think the SS agents turned because they heard a bullet whiz by? What does it sound like to have a high-speed bullet pass by?

The only time I heard the sound of a bullet only, unaccompanied by the muzzle blast, was when I was in what they call the "butts" of a military rifle range and targets were being shot at from 100 yards. This is like an underground bunker, down range of the shooters, from which the targets are run up. The bullets were basically going over our heads, only a few feet above them, and we were able to watch them hitting the targets.

Just as it was described by bystanders in Dealey Plaza, the bullets going over our heads made a definite "crack" like the sound of a firecracker as each one broke the sound barrier going by. It was not an offensive or startling sound but it was definitely audible, and if you were an SS agent guarding the President and you heard this within a few feet of your head, you would probably be trying to identify its source.

As Tom pointed out, the muzzle blast was measured at 130 decibels; well past the point of producing physical pain. Most people believe they know how loud this is, having stood behind rifles being fired, but the blast of a rifle cannot be truly appreciated until you are slightly ahead of the muzzle, as the onlookers on Elm St. were. As I said earlier, this will produce instantaneous and very obvious startle reactions within one second of hearing it. The Zapruder film should have recorded all of this but, instead, we see only onlookers standing immobile like statues.

Here is a very simple way to look at this. Despite the fact the gunpowder burns right past the point the bullet exits the muzzle, some of the heat may be absorbed by the thick metal of the barrel, even though there is only .002 seconds for this transfer to take place. With only this tiny window in time for everything to take place, there is likely still gunpowder burning in the cartridge as the bullet exits the barrel.

If enough heat was absorbed by the barrel to cool the propellant gases to the point the brass cartridge began to shrink, wouldn't this also rob energy from the propellant gases, and drastically reduce the muzzle velocity of the bullet?

Well, I don't think that the cartridge contracts in size due to the propellant cooling off (though that does help), but rather because the cartridge is in tight contact with the barrel and the barrel draws away heat. In fact, if the contact between the cartridge and barrel were perfect, the cartridge temperature would be virtually the same as the barrel temperature. (I say "virtually" because, though brass and steel are great conductors of heat, they are not perfect.)

Electrical engineers study the transfer of heat to heat sinks because power resistors and transistors often need to be cooled, and passive heat-sinking is the cooling method of choice. (Because it is cheep.) When designing a heat sinking system, it is important to minimize the "thermal resistance" from the transistor to the heat sink so as not to delay the transfer of heat. The delay is zero if the thermal resistance is zero. And if there is zero delay, the temperature of the transistor will be precisely the same as the temperature of the heat sink. This despite the fact that heat is continually being produced inside the transistor. A near-zero resistance is accomplished by bolting the transistor directly to the heat sink. (In practice this usually can't be done because the transistor case needs to be electrically isolated from the heat sink.)

Similarly, if a cartridge were in perfect contact with the bore wall, the thermal resistance would be zero and the cartridge would be the same temperature as the barrel. And if that is the case, then the cartridge would contract to the point that it is no longer in tight contact with the bore wall. However, should the contact becomes sufficiently loose, the heat from the propellant would cause the cartridge to expand. The bottom line is the cartridge would be just tight enough against the bore wall that the heat entering it from the propellant would equal the heat loss from it to the barrel. The tightness of the fit would be self-regulating.

An analogy to this self-regulating concept would be a glass of ice water. If someone asked me what the temperature of the water is, I'd say right away and without measuring it that the temperature is precisely 32 degrees Fahrenheit (0 degrees Celsius). Because it has to be. If the temperature were any colder then the water would all freeze. If any warmer, then the ice would all melt. The only temperature at which ice and water can coexist is 32 (0) degrees. It is self regulating, just like the expansion of the rifle cartridge is self regulating.

Unless, of course, the burning powder was producing heat, right up to and past the point the bullet left the barrel, faster than the barrel and chamber were able to absorb that heat. Remember, this whole thing takes place in .002 seconds from the time you pull the trigger.

Look at it this way. Knowing a big cartridge in a short barrelled rifle produces a loud muzzle blast, there is simply no way a 6.5mm Carcano short rifle could have been fired from the Sniper's Nest a mere sixty feet above the heads of the onlookers in Atgens 6, 3.5 - 5.2 seconds before this photo was taken, without very obvious signs of reactions visible on these people.

.... Not only did these carbines and short rifles, shooting cartridges designed for much longer rifles, produce great muzzle flashes, they were also very loud with so much of the combustion taking place outside the barrel. Just imagine how much of a bark was produced by a Carcano carbine with its puny 17 inch barrel!

With this in mind, I cannot help but to point out again how very puzzling the Altgens 6 photo is to me.

From what we are told, this photo corresponds to frame z255 of the Zapruder film. Depending on which version you believe, a short barrelled Carcano rifle firing ammo for a long rifle, has fired one and possibly two shots a mere 60 feet above the heads of the bystanders seen, and slightly to the rear of them, 3.5 to 5.2 seconds before this photo was taken.

And yet, not a single one of them looks remotely startled. How can this be? Those readers with any hunting or military shooting experience will understand exactly what I am getting at here. The unexpected report of a loud short barrelled rifle, ESPECIALY one slightly behind a person, produces instantaneous AND involuntary startle reactions, none of which are visible on the faces of the onlookers. Massive flinches, grimaces and withdrawals all around is what I would have expected to see.

As I have said before many times, the Altgens 6 photo is the most important piece of evidence in the entire case, and deciphering what it has to offer will lead us much closer to what actually took place that day.

Well, we know that the shots were described by many as auto backfires or firecrackers. We know from Altgens 6 that the sounds didn't cause much concern to the bystanders. (Though they could have flinched, since that would have occurred before Altgens 6 was taken.)

And we are reasonably certain that the sounds were made by high-powered rifle(s). (Are we not?)

So what can be deduced from all that? That the rifle(s) had long barrel(s)? Would that fit the testimony and the photo, Robert?

Nothing to do with the length of the barrel. More to do with whether or not the rifle was fitted with a suppressor (silencer) that would produce the firecracker sound. The muzzle blast would be eliminated, but the sound of the bullet breaking the sound barrier would still be heard, and would have a definite "crack" to it. I'm willing to bet the bullet that struck JFK in the back just missed the heads of the two SS agents looking around to see what just happened.

Here is a very simple way to look at this. Despite the fact the gunpowder burns right past the point the bullet exits the muzzle, some of the heat may be absorbed by the thick metal of the barrel, even though there is only .002 seconds for this transfer to take place. With only this tiny window in time for everything to take place, there is likely still gunpowder burning in the cartridge as the bullet exits the barrel.

If enough heat was absorbed by the barrel to cool the propellant gases to the point the brass cartridge began to shrink, wouldn't this also rob energy from the propellant gases, and drastically reduce the muzzle velocity of the bullet?

I must confess that the gigantic fireball of a muzzle flash produced by the M44 carbine is an extreme case, and that I used this photo to dramatize the effect I was attempting to describe. However, while other rifles may produce smaller muzzle flashes, the muzzle flash is still present with these rifles; just not quite so large.

The reason this carbine and some other carbines and short rifles produce such large muzzle flashes has to do with the ammo they shoot.

The Mosin Nagant M44 carbine has a 20.2 inch long barrel, and this carbine was adapted from the original Mosin Nagant M91/30 long rifle with a barrel 29 inches long. The longer M91/30 was loaded with the 7.62x54mmR cartridge, and its extremely long barrel (much longer than a Winchester Model 70) allowed the majority of the gunpowder to burn up before the bullet left the muzzle, thus keeping the muzzle flash to a minimum.

When the M44 was introduced, with its almost 9 inch shorter barrel, no attempt was made to introduce a suitably smaller cartridge, such as was done when the American M1 carbine was introduced. The M44 was designed to fire the same 7.62x54mmR cartridge as was used in the longer M91/30 rifle. Consequently, there was simply "too much powder for the rifle" and a great deal of it burned up outside of the barrel.

Interestingly, precisely the same thing happened with the 6.5mm Carcano when the Italians introduced carbines (17 inch barrels) and short rifles (21 inch barrels). The original Carcano M91 long rifle had a 30 inch long barrel, and its 6.5x52mm cartridge was designed for this barrel. This cartridge was the same cartridge used by both the carbines and the short rifles. As you all know, Oswald's alleged rifle was a 6.5mm Carcano M91/38 short rifle with a 21 inch barrel.

Not only did these carbines and short rifles, shooting cartridges designed for much longer rifles, produce great muzzle flashes, they were also very loud with so much of the combustion taking place outside the barrel. Just imagine how much of a bark was produced by a Carcano carbine with its puny 17 inch barrel!

With this in mind, I cannot help but to point out again how very puzzling the Altgens 6 photo is to me.

From what we are told, this photo corresponds to frame z255 of the Zapruder film. Depending on which version you believe, a short barrelled Carcano rifle firing ammo for a long rifle, has fired one and possibly two shots a mere 60 feet above the heads of the bystanders seen, and slightly to the rear of them, 3.5 to 5.2 seconds before this photo was taken.

And yet, not a single one of them looks remotely startled. How can this be? Those readers with any hunting or military shooting experience will understand exactly what I am getting at here. The unexpected report of a loud short barrelled rifle, ESPECIALY one slightly behind a person, produces instantaneous AND involuntary startle reactions, none of which are visible on the faces of the onlookers. Massive flinches, grimaces and withdrawals all around is what I would have expected to see.

As I have said before many times, the Altgens 6 photo is the most important piece of evidence in the entire case, and deciphering what it has to offer will lead us much closer to what actually took place that day.

Hi Sandy

This is not a bad theory, although you are missing one thing.

The bullet takes about .002 seconds to transit the length of the barrel before it exits. After the bullet exits, the propellant gases are no longer sealed in the barrel by the bullet. Even if the cartridge case did shrink, there is nothing in the barrel under pressure to escape past it.

It is interesting to note that, with a bullet passing through a barrel in .002 seconds, it is possible to wear out a barrel in just six seconds, or the equivalent of 3000 rounds passing through te barrel.

Robert,

Look again and you will see that I said the gas would escape before the bullet exits the barrel. It has to for the theory to work,

Of course, I'm assuming the cartridge can shrink that fast. I don't know if that's possible, but it doesn't have to shrink by much. Just enough for a gas to pass through.

Hi Sandy

I don't believe you quite understand what takes place when a bullet is fired from a rifle.

While the temperature of expanding gases may drop dramatically, the propellant gases from the gunpowder are not merely expanding. Combustion takes place inside the cartridge, and combustion continues down the entire length of the barrel of the rifle. In other words, gunpowder is still burning right at the muzzle, as the bullet exits the barrel.

This is why military rifles, especially the shorter carbine length rifles, have a "flash eliminator" fitted to the muzzle of these rifles.

https://en.wikipedia.org/wiki/Flash_suppressor

As the article explains, its purpose is to reduce the visible signature of the burning gases exiting the muzzle of the barrel, proving that combustion takes place the entire length of the barrel.

If a bullet requires only .002 second to go from the cartridge to the muzzle of the barrel, I think it would be a fair statement to say that not only are the propellant gases pushing it burning and expanding right up until the bullet exits the barrel, they are also increasing, not decreasing, in temperature as the bullet travels down the barrel. The evidence of this is, I believe, the visible muzzle flash of a rifle fired at night, indicating combustion of gunpowder is still taking place at the muzzle of the rifle barrel.

Given that the bullet has left the barrel before the production of hot gases ceases, and that its departure dramatically drops the pressure inside the barrel, and that the cartridge can only cool and shrink after these pressures have been eliminated, I fail to see how any appreciable amount of gas can escape through the space between cartridge and chamber, simply because the cartridge has no chance of shrinking until the bullet leaves the barrel and combustion of gunpowder ceases.

Muzzle flash from Soviet Mosin Nagant M44 carbine

Hi Sandy

This is not a bad theory, although you are missing one thing.

The bullet takes about .002 seconds to transit the length of the barrel before it exits. After the bullet exits, the propellant gases are no longer sealed in the barrel by the bullet. Even if the cartridge case did shrink, there is nothing in the barrel under pressure to escape past it.

It is interesting to note that, with a bullet passing through a barrel in .002 seconds, it is possible to wear out a barrel in just six seconds, or the equivalent of 3000 rounds passing through te barrel.

Ah, the age old problem; how to maintain the principle of free speech without giving free rein to the hate mongers trying to incite the mob.

I worked in the bush as a logger for many years. Every camp I ever worked in had a guy just like McAdams. They were troublemakers, and if they weren't trying to start trouble with the company, they were backstabbing some guy to another guy, just to see if they could get a fight going.

The logging companies believed in free speech, though. These guys were allowed to say anything they wanted, just as long as they were on their way out of camp (never to return) when they did so.

There is a pretty simple rule I learned to live by early on; one guys like McAdams never seem to learn.

"F*ck around, you get hurt; treat others with respect and no pain comes your way."

LOL No sweat, just having fun with ewe.

The plume from the M-1 is greater because it is longer. Being a semi-automatic rifle, this suggests the rifle in the photo has, within a couple of seconds of this photo being taken, fired several shots. Therefore, more gas has escaped from its piston operating system, as it was designed to do. This is why the plume appears to have "dispersed" (disburse means to pay out, as in from a fund) over the shooter's head.

"I don't think you looked carefully enough at the plume coming from the M-1. The plume form the M-1 is much greater than that from the bolt-action rifle. It's just that it has disbursed to the point that it is harder to see near the gun. But it is easy to make out over the shooters head."

Even if a worn bolt action chamber is oval shaped, the expanding brass of the cartridge will swell outwards and "fire fit" to this irregular shape, and make an effective seal against escaping gases. This is a phenomenon that plagues handloaders that practice a type of cartridge re-sizing called "neck sizing", in which only the neck of the cartridge is re-sized.

I can consider trace elements escaping from this seal, but not the great plume depicted in this photo.

Sorry, Pat, I cannot accept this photo as valid. I have shot too many bolt action rifles, and been near bolt action rifles being shot, to believe this. I would think, after all these years, I would have noticed this before; especially hunting in cold damp weather.

Here is a diagram of the inside of a bolt action rifle barrel, showing a cartridge in the chamber.

Note that chamber and barrel are machined from one piece of steel. Not shown is the face of the bolt that holds the cartridge in place.

When the cartridge is fired, the bullet does not immediately leave the cartridge. It requires great internal cartridge pressure, from the combustion of its gunpowder, to overcome inertia and begin moving the bullet down the barrel. Before the bullet leaves the cartridge, with the cartridge being a sealed unit, these pressures act on the thin walls of the brass cartridge, moulding it to the inside of the chamber and preventing gases from escaping past the cartridge toward the shooter.

Unless that photo was re-touched, we are likely looking at the result of a ruptured brass cartridge or ruptured primer. When such a thing occurs, there are small gas vent holes on the sides of the forward end of the receiver (many times only one) that direct gases harmlessly out to the side, instead of toward the shooter's face. The beginning of the plume, in the photo above, is precisely where Winchester puts the single gas vent on their Model 70.

Gas vent shown as small hole on the forward part (right) of the Model 70 receiver, just under scope base and serial number.

Seriously, Pat, there is as much of a plume coming from the bolt action rifle as there is from the M-1. How could that be possible?

I spoke to Robin Unger, and he maintains the still of Calvery, Hicks and Reed is most definitely from James Darnell's film. However, I cannot find this still in that film.

As I pointed out in Jim D's thread, I would not expect a bolt action rifle to produce even a fraction of the escaped gases toward the shooter that a revolver would produce.

As can be seen in the two photos below, there is a tiny gap between the cylinder of a revolver and the barrel of a revolver.

This gap is referred to as the "Cylinder-Barrel Gap" or just Cylinder Gap, for short. As the cartridges for a revolver are in the revolving chamber, it is necessary for a fired bullet to cross this gap on its way to the barrel, where it first encounters the rear part of the barrel that is referred to as the "forcing cone".

If this gap were made too small, it would prevent the revolving chamber from being able to turn past the forcing cone, especially after a couple of rounds have been fired and the metal forcing cone has heated up and expanded somewhat.

This cylinder gap is an inherent fault in all revolvers, and explains why revolvers are so loud, as escaping gases are directed laterally and back from this gap. It also helps to explain the lower muzzle velocities of revolvers as, without a tight seal, propellant gases are unable to apply their full force to an exiting bullet.

As you can imagine, with the shooters hand so close to this gap, it is inevitable there will be gunshot residue on his shooting hand.

OTOH, the rifle barrel and chamber are machined from one piece of steel. Propellant gases are only allowed to escape at the muzzle of the rifle, after the bullet exits. Even if the brass cartridge is not a tight fit in a worn chamber, as soon as the gunpowder is ignited, and before the bullet leaves the cartridges, internal cartridge pressures rise dramatically with the burning powder and, before the pressure rises enough to make the bullet begin to move, these pressures are enough to swell the thin walls of the soft brass cartridge outward; effectively "form fitting" the brass cartridge to the chamber and making a seal that will not allow propellant gases to escape rearward.

There is a gas port on the side of the chamber of most bolt action rifles but, this is only here in the event of a ruptured cartridge or primer to give escaping gases somewhere to go beside in the face of the shooter.

Therefore, the only time a shooter's hands should be anywhere near these gases is when he pulls the bolt back to extract a spent cartridge, and lingering gases in the chamber are drawn out by the vacuum the extracting empty cartridge creates.

Robert,

Thanks for your comments. What you say makes perfect sense.

I need some time to think about the ramifications of this information. If all I knew was what you wrote here, my conclusion would be that no testing (nitrate or NAA) could detect the firing of a rifle. But that appears not to be the case. As I recall, the WC (FBI?) performed NAA tests on individuals who had fired a Carcano, and every one tested positive on their cheek. So apparently the Carcano does leak sufficiently for the sensitive NAA test to detect GSRs.

I'll keep what you wrote here in mind, let others comment on it, and use it when conclusions can be drawn from it..

When you eject a spent casing by pulling the bolt back, immediately after firing a shot, there is always a wisp of smoke that comes out from the open chamber. This is because as you draw the bolt back, the tightly fitting casing seals against the chamber walls, creating a vacuum much like the plunger in a syringe and drawing in air from the muzzle.

I would not believe every test conducted by the FBI.

Plume of gsr from an M-1 carbine

Apples and oranges, Pat. The M-1 carbine is a semi-automatic rifle. I was referring to bolt action rifles, which is what Oswald allegedly used.

Piston operated semi-automatic rifles, such as the M-1 carbine, have a gas port partway down the inside of the barrel that allows propellant gases to go through this port and force a short piston under the barrel rearward, opening a rotating bolt to eject an empty shell and deliver a fresh cartridge into the chamber.

The plume you see in the photo is spent propellant gas from this piston. The bolt action rifle does not do this.

With that kind of fanfare, someone must have been very confident these notes were actually written by Fritz.

How does a person check something like this out? Can we simply phone NARA and gently suggest these enshrined notes are fake, and let them tell us how they determined they were genuine?

So now it needs to be proven that the notes are real, instead of Scully proving they are fake.

The burden is on him not on you or anyone else.

The last two weeks I have seen some serious filthy denials at JFKFacts that make David Irving look like a boy scout.

http://www.jfk-info.com/arrb1120.htm

Bart

My biggest problem with Tom Scully is attempting to decipher his cryptic posts. Sometimes I just sit back and ask, "What in the name of all that is holy are you rambling on about, boy!?"

There seems to be some argument about the origin of some stills of Gloria Calvery, following the assassination. I was under the impression they were from the Darnell film, but are they?

Yes, I recall that, Pat. Since that time, though, I have had a chance to think this matter over, and there is something very odd about these notes, if they are indeed written by Fritz.

If they were written several days after the interrogation, why do they look like the kind of hasty shorthand someone would use in a situation where he really did not have time to write and follow the interrogation at the same time? It must be remembered that Fritz never made these notes public in his lifetime, and they should be viewed from that perspective.

With that in mind, here are several possible scenarios. Feel free to add to them, if you feel I have missed something.

1) Fritz actually did take notes during the investigation, contrary to his WC testimony, but never revealed them to anyone. The possible reasons for not revealing them are:

i) he felt they were nobody's business but his own

ii) he deeply regretted writing things such as "out in front with Bill Shelley" and thought it best to keep his notes private

2) Several days after the interrogation, with the presence of the FBI in the investigation, Fritz may have realized how unprofessional it was to conduct an interrogation without a tape recorder or stenographer present, and wrote his notes in such a way that, should someone demand to see these notes, it would appear he had written them during the interrogation. As no one seems to have requested these notes, he may have elected not to release them for reasons i) and ii) above.

I believe Fritz testifying that he wrote notes several days after the interrogation is an expression of his confidence he would no longer be in trouble for not recording the interrogation.

As I pointed out in Jim D's thread, I would not expect a bolt action rifle to produce even a fraction of the escaped gases toward the shooter that a revolver would produce.

As can be seen in the two photos below, there is a tiny gap between the cylinder of a revolver and the barrel of a revolver.

This gap is referred to as the "Cylinder-Barrel Gap" or just Cylinder Gap, for short. As the cartridges for a revolver are in the revolving chamber, it is necessary for a fired bullet to cross this gap on its way to the barrel, where it first encounters the rear part of the barrel that is referred to as the "forcing cone".

If this gap were made too small, it would prevent the revolving chamber from being able to turn past the forcing cone, especially after a couple of rounds have been fired and the metal forcing cone has heated up and expanded somewhat.

This cylinder gap is an inherent fault in all revolvers, and explains why revolvers are so loud, as escaping gases are directed laterally and back from this gap. It also helps to explain the lower muzzle velocities of revolvers as, without a tight seal, propellant gases are unable to apply their full force to an exiting bullet.

As you can imagine, with the shooters hand so close to this gap, it is inevitable there will be gunshot residue on his shooting hand.

OTOH, the rifle barrel and chamber are machined from one piece of steel. Propellant gases are only allowed to escape at the muzzle of the rifle, after the bullet exits. Even if the brass cartridge is not a tight fit in a worn chamber, as soon as the gunpowder is ignited, and before the bullet leaves the cartridge, internal cartridge pressures rise dramatically with the burning powder and, before the pressure rises enough to make the bullet begin to move, these pressures are enough to swell the thin walls of the soft brass cartridge outward; effectively "form fitting" the brass cartridge to the chamber and making a seal that will not allow propellant gases to escape rearward.

There is a gas port on the side of the chamber of most bolt action rifles but, this is only here in the event of a ruptured cartridge or primer to give escaping gases somewhere to go beside in the face of the shooter.

Therefore, the only time a shooter's hands should be anywhere near these gases is when he pulls the bolt back to extract a spent cartridge, and lingering gases in the chamber are drawn out by the vacuum the extracting empty cartridge creates.

Well, I can see the three empty cartridges being cleaned of fingerprints before he departed the 6th floor (I know, John, I know; much simpler just to stick them in his pocket, right? LOL) but the one that puzzles me is the live cartridge that was found in the chamber of the rifle by the DPD. Did he wear gloves while loading the cartridges into the clip?

Also, what about fingerprints on the clip itself? It apparently did not fall out of the magazine until the rifle was halfway to DPD headquarters. How did he wipe the prints off of it?