Ballistic Testing, Inconclusive Results Vs. Negative Results

[Bill Brown]

UNDERSTANDING BALLISTIC TESTING AND INCONCLUSIVE RESULTS VERSUS NEGATIVE RESULTS

Before it was sold, Oswald's revolver was rechambered but not rebarreled. This was so that the revolver could fire the longer (and skinnier) .38 Special instead of the .38 S&W (a better selling point).

The original chamber was too short for the longer .38 Special bullet. The .38 Special bullet is generally accepted as being a higher quality ammunition than the .38 S&W. However, since the revolver still had the original barrel, the skinnier (less diameter) .38 Special bullet traveled in an inconsistent path down the barrel, creating inconsistent markings from one bullet to the next and therefore made ballistic testing difficult.

This is the only reason the bullets removed from Tippit's body during the autopsy couldn't be matched to the weapon (sans Joseph Nicol, who was able to match one of the bullets to the weapon).

But most importantly, saying the bullets couldn't be matched to the revolver does NOT rule out the revolver as being responsible for those bullets.  The ballistic tests were simply inconclusive.

[Tim Nickerson]

UNDERSTANDING BALLISTIC TESTING AND INCONCLUSIVE RESULTS VERSUS NEGATIVE RESULTS

Before it was sold, Oswald's revolver was rechambered but not rebarreled. This was so that the revolver could fire the longer (and skinnier) .38 Special instead of the .38 S&W (a better selling point).

The original chamber was too short for the longer .38 Special bullet. The .38 Special bullet is generally accepted as being a higher quality ammunition than the .38 S&W. However, since the revolver still had the original barrel, the skinnier (less diameter) .38 Special bullet traveled in an inconsistent path down the barrel, creating inconsistent markings from one bullet to the next and therefore made ballistic testing difficult.

This is the only reason the bullets removed from Tippit's body during the autopsy couldn't be matched to the weapon (sans Joseph Nicol, who was able to match one of the bullets to the weapon).

But most importantly, saying the bullets couldn't be matched to the revolver does NOT rule out the revolver as being responsible for those bullets.  The ballistic tests were simply inconclusive.

Nicol's standard was obviously lower than that of the FBI Firearms Lab specialists.

[John Mytton]

Mr. EISENBERG. Mr. Chairman, may I have this admitted? That would be 625.
(The item described was marked Commission Exhibit No. 625 and received in evidence.)
Mr. EISENBERG. These arrows, Mr. Nicol, can you explain why they are different?
Mr. NICOL. This was one I made up originally and then decided that the illustration would be ample with one arrow in that one position.
Mr. DULLES. The one that is being admitted is the one-arrow photograph.
Mr. EISENBERG. The arrows are placed on mechanically after the photograph is developed?
Mr. NICOL. That is correct.
Mr. EISENBERG. And therefore it can vary?
Mr. NICOL. Yes. This is not a part of the photographic process.
Mr. EISENBERG. What is the magnification here, Mr. Nicol?
Mr. NICOL. It would be pretty close to 25 to 30 diameters. I cannot measure exactly the magnification.
Mr. NICOL. This illustrates some of the lines, not all of them, that I saw on a comparison of 502 and K-3. At the position of the arrow, you are looking at the top of the groove; adjacent to it in the lower portion is a land impression. And on that shoulder there are approximately five or six matching lines. They are very fine striations. These would be indicative of the fact that the same portion of the barrel had ridden on both projectiles.
Mr. EISENBERG. Well, now, there seems to be significantly less markings here than on the bullets which were seen earlier, which had come from the rifle. Does that same condition pertain when the bullet is viewed under the microscope?
Mr. NICOL. Yes. Of course, we are dealing with two different types of ammunition. One is a lead projectile, and the other is a metal-case projectile. And the ability of the metal-case projectile to pick up and retain fine striations, even in spite of distortion and mutilation, far exceeds what the lead projectile will do. Furthermore, the lead being a soft and low-melting-point material is more subject to erosion of hot gases. So that there are many more variables in the reproduction in terms of a lead projectile as over against a metal-case projectile.
Mr. EISENBERG. You found enough similarities to satisfy yourself that there is an identification here?
Mr. NICOL. I am satisfied that the two projectiles came from the same weapon.



JohnM

[John Corbett]

Just one minor point. The revolver was originally chambered for the British .38-200 round, very similar to the S&W .38 also known as the S&W .38 Short. The 200 indicates the number of grains in the bullet. It was made for the Lend Lease program prior to the US entering WWII. It was called the S&W Victory model, a variant of the popular S&W Model 10 which was introduced in 1898 in .38 Special. It was chosen by many police departments throughout the country. The Victory models were returned to the US after the war and rechambered. Oswald's also received a snub nose 2" barrel. I'm guessing the original barrels were just sawed down to create a snub nosed revolver, which were preferred by plain clothes officers who carried their weapons concealed.

S&W also provided the Victory model to the US Navy which was chambered for the S&W .38. Both the S&W .38 and the S&W .38-200 had a bullet diameter of .361 inches. The following article mentions both rounds. I haven't verified this, but my guess is that the Victory model sold to the Navy and the one provided to the UK under the Lend Lease program were one and the same and could fire either cartridge interchangeably.

https://www.americanrifleman.org/content/v-is-for-victory-the-smith-wesson-victory-model-revolver/