This point would require further research: from
http://youknowwhokilledyoudontyou.blogspot.com/2011/02/innocent-man-page-14.html from the book "The Innocent Man" by David Shaw Page 14
A TALE OF TWO GUNS
"The first thing we find when we examine the police evidence is amazing: the same gun could not have fired these two bullets. Different guns fired the two bullets into Sheila Caffell’s throat.
This goes entirely against the police case and on a practical level destroys almost everything the prosecution and judge claimed at Jeremy’s trial regarding the murders themselves.
The fact that two different guns were used to kill Sheila Caffell seems extraordinarily bizarre. Why would Sheila, if she suicided in the main bedroom, shoot herself with one gun and then select another gun to finish herself off? It’s equally ridiculous to suggest that Jeremy engineered such a scenario that his sister just assumed the ‘suicide position’ while he pumped one bullet into her throat, then discarded that weapon and went off to find another gun with which to fire the fatal shot.
Even more amazing is the fact that the family Anschutz rifle that lay across Sheila’s chest was not the gun that fired the fatal shot. The Anschutz rifle was responsible for inflicting the first, non-fatal wound (bullet PV/20). But there is no doubt that another rifle was used to inflict the fatal wound (bullet PV/19).
The Anschutz rifle did not have narrow grooves and consequently a series of wide lands would have been left upon the surface of any bullet fired from that rifle, as is evidenced from the bullets conclusively linked to this exhibit. Only one of the two bullets (PV/20 – non fatal bullet) fired into Sheila had the wider lands that matched those of the rifle PC Bird photographed on top of Sheila’s corpse. The other bullet (PV/19 - fatal) had narrow lands which meant that the barrel of the rifle which fired the fatal bullet (PV/19) must have had narrow grooves.
The Anschutz rifle simply could not have had narrow lands and wider lands at the same time. No gun can. It could not have had narrow grooves and wider grooves at the same time. Bullet PV/19 had narrow lands; PV/20 wider lands. It’s that simple. The two bullets fired into Sheila Caffell’s throat possess different ballistic characteristics.
The ballistic expert Malcolm Fletcher described the type of bullets he examined when looking at all 25 of the crime scene bullets given to him by Essex police. These ‘General Examination Records’ describe some of the bullets as 22 LR Bullets, others as .22 bullets and one as a bullet. No explanation was ever put forward as to why the same type of bullets were described differently like this. Why did the ballistic expert not describe all 25 crime scene bullets as all being .22 LR Bullets if that is what they were? The variation in the type of bullets he described suggests that a variety of different types of .22 bullets were used in the shootings, but the ballistic expert chose not to pursue this possibility.
Malcolm Fletcher examined the crime scene bullets to see whether or not the bullets had narrow or wide lands (N/L), how many lands and grooves each bullet had (L/G) and if there was a presence or not of rifling marks (R/M). The details the ballistic expert recorded for the two bullets fired into Sheila’s throat are as follows:
PV/20: weighing 1.5453 grams, did not have Narrow Lands upon its surface, but had the same number of lands and grooves as the (Anschutz) rifle and upon which was found corresponding rifling marks that matched those of control ammunition fired from the (Anschutz) rifle.
This information tells us that the Anschutz rifle that was photographed on top of Sheila’s body produced the precise characteristics upon all the bullets which were fired from it, and these characteristics explicitly match bullet PV/20. Other Anschutz-fired bullets are all consistent in their information and match the information garnered from PV/20 to a tee. So there is little dispute that bullet PV/20 was indeed fired form the Anschutz rifle found on Sheila’s chest as claimed. But PV/20 was not the bullet that killed Sheila Caffell. That was PV/19.
The recorded information for this bullet is equally clear:
PV/19: weighing 2.16 grams, only 3/4 lands and grooves upon its surface, it has narrow lands and there were no rifling marks found.
On every single factor – weight, lands, grooves and rifling marks, the two bullets found in Sheila do not align. It’s like looking at two utterly different fingerprints and being asked to believe they came from the same person.
PV/20 had eight lands and grooves upon its surface. PV/ 19 had a maximum of six lands and grooves upon its surface. No gun causes a different number of lands and grooves to be present upon two bullets from the same match of ammunition fired consecutively from it.
The police officers who digested this information were well aware that if the two bullets that wounded and killed Sheila Caffell had a different number of lands and grooves as well as significantly different weights and rifling marks upon their respective surfaces that the same gun could not have fired both bullets. So why was this elemental and fundamental truth suppressed? The police knew that it was a physical impossibility that the Anschutz rifle was solely responsible for all the murders at White House Farm, but they went to court and swore under oath that one gun, and one gun only, had fired all 25 rounds."
