Pat Speer Posted May 21, 2016 Share Posted May 21, 2016 There has been repeated speculation within this thread that the amount of residue found on a shooter's hand should be in proportion to the number of shots he's supposedly fired. I posted the charts so you could see that this has been tested and that it is not true. The results of the study as recorded in the chart (below) don't prove that GSR accumulation isn't linear. It proves that it is sporadic. And, on average, seemingly in a cumulative way. That's all it proves. The barium deposited on one shooter's hand (or by one gun?) increased, not three-fold, but 13-fold by firing three shots rather than one! Yet on another, the barium decreased 22% when firing three shots instead of one. If you're thinking that averaging will give a true picture of how linear the accumulation is, well yes, that is true... if there were a few dozen test results to average. But five tests is too small a sample to get an accurate average. BTW, does each row in the table represent a different shooter? Each of whom fires different guns? Or does each row represent a different gun? (The complete documentation would be most useful, hint, hint.) Each line represented a different gun, but the tests of multiple firings did not represent a continuation of the test for one firing. They shot the gun once and tested the residue, then shot the gun three times and tested the residue. The nature of the paraffin casts and the tests prohibited them from testing the cast after one shot, then testing the same cast after three shots. So the averages are all we have to go by. Link to comment Share on other sites More sharing options...
Tom Neal Posted May 22, 2016 Share Posted May 22, 2016 (edited) So, the S & W Victory Models were converted to shoot .38 Special cartridges by re-chambering. How they did this precisely is a bit of a mystery to me unless, of course, the .38 S & W revolving chamber was merely swapped out for a .38 Special revolving chamber. You see, they simply couldn't just drill the chambers out to a larger size, as the .38 S & W chamber was already .3855 inches in diameter, and the .38 Special chamber was a mere .379 inches in diameter. A chamber liner, possibly? Bob, I still haven't had any time to research but I can elaborate on my earlier post regarding re-chambering: This is still from memory, so subject to verification - The smaller diameter, but longer .38 Special cartridge will only fit 2/3 of its length into the cylinder, so the chamber is bored at the smaller (.379) diameter until long enough to accept the entire cartridge. The first third of the cartridge fits into the correct diameter bore, but the remaining 2/3 thirds is a loose fit due to the larger .38 S&W bore diameter. A .38 Special cartridge fired in a re-chambered weapon produces a spent hull that has an expanded diameter at its end due to 2/3 of the cartridge residing in the oversize bore when it was fired. Considering the shallow rifling grooves in a .38 S & W barrel, I would be surprised if the .38 Special bullets fired from Oswald's alleged revolver had rifling impressions on them that amounted to more than light scratches.As I said earlier, the bullets in JDT's body could not be ballistically matched to "LHO's" .38 and IMO this re-chambering is the reason. As far as LHO shooting JDT: no ballistic comparison was possible There were no fingerprints on the cartridges At the murder scene they were identified as from an automatic but the cartridges in evidence were not ejected from an automatic The empty hulls were found on the ground at the crime scene - why would LHO empty the cylinder onto the ground leaving potentially incriminating evidence behind? Edited May 22, 2016 by Tom Neal Link to comment Share on other sites More sharing options...
Tom Neal Posted May 22, 2016 Share Posted May 22, 2016 Thought I'd share this lovely photo with you, showing the air gap flash from a .38 Special revolver. It would be interesting to see a photo of a .38 S&W re-chambered for .38 Special ammo. With that oversize bore and loose fit of the rear 2/3 of the bullet it would likely produce a bigger flash and more GSR...seems reasonable, anyway. Link to comment Share on other sites More sharing options...
Tom Neal Posted May 22, 2016 Share Posted May 22, 2016 (edited) The complete documentation would be most useful, hint, hint.Agreed, and despite multiple requests for this, we are still getting bits and pieces that generate more questions than answers. Bob P. would you like to see the entire document, also? ANYONE ELSE? Each line represented a different gun, They shot the gun once and tested the residue, then shot the gun three times and tested the residue. MR. SPEER: The varying quantity of GSR deposits could be explained if we knew whether these five .38s were all revolvers or a mixture of revolvers and semi-automatics. Edited May 22, 2016 by Tom Neal Link to comment Share on other sites More sharing options...
Robert Prudhomme Posted May 22, 2016 Share Posted May 22, 2016 (edited) "This is still from memory, so subject to verification - The smaller diameter, but longer .38 Special cartridge will only fit 2/3 of its length into the cylinder, so the chamber is bored at the smaller (.357) diameter until long enough to accept the entire cartridge. The first third of the cartridge fits into the correct diameter bore, but the remaining 2/3 thirds is a loose fit due to the larger .38 S&W bore diameter. A .38 Special cartridge fired in a re-chambered weapon produces a spent hull that has an expanded diameter at its end due to 2/3 of the cartridge residing in the oversize bore when it was fired." Hi Tom This is the part I don't understand, assuming they kept the original .38 Victory revolving chamber and modified it to accommodate the .38 Special cartridge. If the entire .38 S&W chamber was .3855 inches in diameter, and the .38 Special cartridge was a mere .379 inches in diameter, how could you bore the .38 S&W chamber out, if you needed to make it smaller? Edited May 22, 2016 by Robert Prudhomme Link to comment Share on other sites More sharing options...
Robert Prudhomme Posted May 22, 2016 Share Posted May 22, 2016 (edited) I think I just got it. If the .38 S&W brass casing was only .775 inches long, and the .38 S&W chamber was long enough to accommodate the longer .38 Special brass casing (1.155 inches long), did that mean the forward part of the .38 S&W chamber narrowed down to the diameter of the .38 S&W bullet, that diameter being .361 inch? Therefore, all they had to do was drill the narrower (.361 inch) part of the chamber out to .380 inch to accommodate the .379 inch diameter .38 Special brass casing. Perfect. And THAT is why everyone speaks of the .38 Special casing being swollen out at the base, as it is trying to fill a chamber .3855 inches in diameter. P.S. I'm still wrong. The .38 S&W chamber is .3855 inches at the forward end, but flares out to .3865 inches toward the base. Edited May 22, 2016 by Robert Prudhomme Link to comment Share on other sites More sharing options...
Tom Neal Posted May 22, 2016 Share Posted May 22, 2016 (edited) I think I just got it. If the .38 S&W brass casing was only .775 inches long, and the .38 S&W chamber was long enough to accommodate the longer .38 Special brass casing (1.155 inches long), did that mean the forward part of the .38 S&W chamber narrowed down to the diameter of the .38 S&W bullet, that diameter being .361 inch? Therefore, all they had to do was drill the narrower (.361 inch) part of the chamber out to .380 inch to accommodate the .379 inch diameter .38 Special brass casing. Perfect. And THAT is why everyone speaks of the .38 Special casing being swollen out at the base, as it is trying to fill a chamber .3855 inches in diameter. P.S. I'm still wrong. The .38 S&W chamber is .3855 inches at the forward end, but flares out to .3865 inches toward the base. Bob, In my earlier post I incorrectly stated the bullet diameter as the cylinder bore diameter, but I see you have used the correct dimensions. Still from memory, but I believe the cylinder throat diameter is only .358" so what they are doing is reaming out the throat to accommodate the .379" diameter .38 Special cartridge. The throat is long enough to allow full insertion of the longer bullet and still retain an adequate throat length. So the first 1/3 of the cartridge is inserted into the part of the cylinder bore that matches the diameter of a .38 Special revolver cylinder bore. I should have time tomorrow to check the throat diameter from my records which I made at least 3 years ago. Hopefully, I can find them... Edited May 22, 2016 by Tom Neal Link to comment Share on other sites More sharing options...
Sandy Larsen Posted May 22, 2016 Author Share Posted May 22, 2016 (edited) As far as LHO shooting JDT:no ballistic comparison was possible There were no fingerprints on the cartridges At the murder scene they were identified as from an automatic but the cartridges in evidence were not ejected from an automatic The empty hulls were found on the ground at the crime scene - why would LHO empty the cylinder onto the ground leaving potentially incriminating evidence behind? Tom, I'm interested in knowing things about the Tippit shooting that tends to exonerate Oswald. I thought that one of those things was that the bullet shells were identified as being ejected from an automatic. (That would really be semi-automatic, right?) Now I learn that the shells were later found not to have been ejected from an automatic. Is there an innocent explanation for this change? Edited May 22, 2016 by Sandy Larsen Link to comment Share on other sites More sharing options...
Pat Speer Posted May 22, 2016 Share Posted May 22, 2016 There was but one paragraph describing Table 4. It said all five were revolvers. But that's really beside the point. GSR levels are not constant. They vary from type of weapon to type of weapon, from specific weapon to specific weapon, from type of ammunition to type of ammunition, and even specific cartridge to specific cartridge. And the wind is a huge factor. As a result the hands of someone who shot someone three times with a .38 may retain less residue than the hands of someone else firing that same revolver twice in a simulation. Link to comment Share on other sites More sharing options...
Robert Prudhomme Posted May 22, 2016 Share Posted May 22, 2016 (edited) I think I just got it. If the .38 S&W brass casing was only .775 inches long, and the .38 S&W chamber was long enough to accommodate the longer .38 Special brass casing (1.155 inches long), did that mean the forward part of the .38 S&W chamber narrowed down to the diameter of the .38 S&W bullet, that diameter being .361 inch? Therefore, all they had to do was drill the narrower (.361 inch) part of the chamber out to .380 inch to accommodate the .379 inch diameter .38 Special brass casing. Perfect. And THAT is why everyone speaks of the .38 Special casing being swollen out at the base, as it is trying to fill a chamber .3855 inches in diameter. P.S. I'm still wrong. The .38 S&W chamber is .3855 inches at the forward end, but flares out to .3865 inches toward the base. Bob, In my earlier post I incorrectly stated the bullet diameter as the cylinder bore diameter, but I see you have used the correct dimensions. Still from memory, but I believe the cylinder throat diameter is only .358" so what they are doing is reaming out the throat to accommodate the .379" diameter .38 Special cartridge. The throat is long enough to allow full insertion of the longer bullet and still retain an adequate throat length. So the first 1/3 of the cartridge is inserted into the part of the cylinder bore that matches the diameter of a .38 Special revolver cylinder bore. I should have time tomorrow to check the throat diameter from my records which I made at least 3 years ago. Hopefully, I can find them... Hi Tom Close but, the throat diameter for the .38 S&W would be .361 inches, the same diameter as the .38 S&W bullet, and would be drilled out to .379 inches to accommodate the .38 Special casing. The .38 Special bullet diameter is .357 inches, while the .38 S&W bullet diameter is .361 inches; .004 inch difference This is why re-chambering a .38 S&W to a .38 Special is a somewhat questionable exercise, as you are now shooting a .38 Special bullet that is .004 inch smaller in diameter through the .38 S&W barrel. There will be far less of the riflings gripping the bullet and there is also a chance for propellant gases to blow past the bullet in the barrel. However, considering that the barrel of Oswald's alleged revolver was cut shorter anyways, and that most revolvers are used within spitting distance of their victims, making accuracy unimportant, these things probably don't make a lot of difference. P.S. Are there any photos available of spent bullets fired from Oswald's alleged revolver? Edited May 22, 2016 by Robert Prudhomme Link to comment Share on other sites More sharing options...
Tom Neal Posted May 22, 2016 Share Posted May 22, 2016 (edited) There was but one paragraph describing Table 4. It said all five were revolvers. And this is why as I have requested, you should produce the document or at least the page. What's the problem here Mr. Spear? Just can't share your toys? Does it make you feel smarter than the rest of us, when you correct our assumptions based upon the limited info you provide? But that's really beside the point. GSR levels are not constant.No, it is NOT beside the point. A revolver has 6 different chambers. Each shot would produce DIFFERENT characteristics. This would produce different GSR levels. The only question is how MUCH different. If the pattern repeated after a reload we would have an answer. As I've ALREADY pointed out, someone with a greater knowledge of guns may spot something you didn't know. e.g. Contrary to your reply, it DOES matter if they were all revolvers or not. You have chosen to limit your "gifts" to a degree that renders the information useless, and I have NO desire to beg you for info that you should have provided. Tom Edited May 22, 2016 by Tom Neal Link to comment Share on other sites More sharing options...
Tom Neal Posted May 22, 2016 Share Posted May 22, 2016 (edited) Hi Tom Close but, the throat diameter for the .38 S&W would be .361 inches, the same diameter as the .38 S&W bullet, and would be drilled out to .379 inches to accommodate the .38 Special casing. The .38 Special bullet diameter is .357 inches. IF the throat diameter of the cylinder bore of a .38 SW actually is .379 per your statement above, then the .38 Special cartridge with its .379 diameter would fit ALL the way into the chamber despite its greater length. However, it does not. It only goes in about 2/3 of its length. The throat has to be increased in diameter with a reamer by the difference in length of the S v. the SW. I'll see if I can find a diagram, but subject to my memory the cylinder throat diameter is smaller than the bore diameter in both the SW and Special revolvers. EDIT: Quote: "I have taken a look at one of these converted Victories up close. I can see that the chambers were bored to the length of the special case, with the [length of the] extended bore in the diameter of the special. Therefore you can still see where the case of the .38 S&W would end, in other words two distinct diameters. I loaded it with dummy .38 specials and there was a little wiggle on some of the chambers but not much and none on some." Quote: Q: Is there a STANDARD SPEC for a .38 SPL cylinder THROAT? A: All of my S&W's in 357 and 38 are spot on at .358". That size works well with both cast and jacketed bullets. Tom Edited May 22, 2016 by Tom Neal Link to comment Share on other sites More sharing options...
Tom Neal Posted May 22, 2016 Share Posted May 22, 2016 (edited) As far as LHO shooting JDT: no ballistic comparison was possible There were no fingerprints on the cartridges At the murder scene they were identified as from an automatic but the cartridges in evidence were not ejected from an automatic The empty hulls were found on the ground at the crime scene - why would LHO empty the cylinder onto the ground leaving potentially incriminating evidence behind? Tom, I'm interested in knowing things about the Tippit shooting that tends to exonerate Oswald. I thought that one of those things was that the bullet shells were identified as being ejected from an automatic. (That would really be semi-automatic, right?) Now I learn that the shells were later found not to have been ejected from an automatic. Is there an innocent explanation for this change? Sandy, You are correct regarding auto vs. semi-auto, but when referring to these cartridges, the term "auto" was used in the report. The ejector leaves a mark on the cartridge which was observed and reported by the officer who found them. The extant cartridges have no such mark. As far as I know, supporting documentation confirms this but I don't have it. Jim Garrison Playboy October 1967 Interview: " Of the four cartridges found at the scene, two were Winchesters and two were Remingtons — but of the four bullets found in Officer Tippit’s body, three were Winchesters and one was a Remington! The last time I looked, the Remington–Peters Manufacturing Company was not in the habit of slipping Winchester bullets into its cartridges, nor was the Winchester–Western Manufacturing Company putting Remington bullets into its cartridges." Tom Edited May 22, 2016 by Tom Neal Link to comment Share on other sites More sharing options...
Robert Prudhomme Posted May 22, 2016 Share Posted May 22, 2016 Hi Tom Close but, the throat diameter for the .38 S&W would be .361 inches, the same diameter as the .38 S&W bullet, and would be drilled out to .379 inches to accommodate the .38 Special casing. The .38 Special bullet diameter is .357 inches. IF the throat diameter of the cylinder bore of a .38 SW actually is .379 per your statement above, then the .38 Special cartridge with its .357 diameter would fit ALL the way into the chamber despite its greater length. However, it does not. It only goes in about 2/3 of its length. The throat has to be increased in diameter with a reamer by the difference in length of the S v. the SW. I'll see if I can find a diagram, but subject to my memory the cylinder throat diameter is smaller than the bore diameter in both the SW and Special revolvers. Tom Hi Tom If you look again at the diagrams, you will see that the .38 Special is smaller in diameter in both bullet and brass casing. Bullet = .357 inch Casing = .379 inch The .38 S&W is larger in diameter in both bullet and brass casing. Bullet = .361 inch Casing = .3855 inch The manufacturer would not make the chamber of the .38 S&W .379 inches in diameter, if the diameter of the casing was .3855 inches and flared out to .3865 inches at the base of the cartridge. I did not say the .38 S&W chamber was .379 inches in diameter, and I don't know how you got that impression. Obviously, the .38 S&W chamber narrows down from .3855 inches to .361 inches at the point where the bullet meets the neck of the brass casing. It is this .361 inch diameter section of the chamber that must be bored out to accommodate the longer .38 Special casing with a diameter of .379 inches. Link to comment Share on other sites More sharing options...
Robert Prudhomme Posted May 22, 2016 Share Posted May 22, 2016 (edited) Tom Neal said: "No, it is NOT beside the point. A revolver has 6 different chambers. Each shot would produce DIFFERENT characteristics. This would produce different GSR levels. The only question is how MUCH different. If the pattern repeated after a reload we would have an answer. As I've ALREADY pointed out, someone with a greater knowledge of guns may spot something you didn't know. e.g. Contrary to your reply, it DOES matter if they were all revolvers or not." I think the answer to this question, assuming all the weapons in the testing were revolvers, lies in this photo: As can be seen in this photo, there is quite a large gap between the chamber of the revolver, holding the cartridges, and the barrel of the revolver. This is known, in some circles, as the "barrel cylinder gap" and, while it may appear to be poor workmanship, this large gap is a necessary component of a revolver, without which it could not function. The above photo demonstrates just how ridiculously large this gap is, and the great potential there is for losing propellant gases here. The reason this gap is so large is that, with each shot fired, the metal components on either side of this gap heat up and expand. If the gap, in a cold revolver, was made small enough to almost seal this gap off, by the time the second shot was fired the metal on either side of this gap would have expanded to the point the two surfaces would be in contact with each other, and the chamber would no longer turn. If the metal components did not expand with each shot, there would be virtually no barrel cylinder gap. As the size of this gap would determine the volume of GSR escaping through it, the real questions should be how much time was allowed between shots (giving the metal a chance to cool down and contract) and was an equal amount of time allowed between each shot? Edited May 22, 2016 by Robert Prudhomme Link to comment Share on other sites More sharing options...
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