Author Topic: Drawback Analysis  (Read 9144 times)

0 Members and 1 Guest are viewing this topic.

Offline Patti

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 13193
Drawback Analysis
« on: March 04, 2015, 08:28:PM »
A central plank of the prosecution's case is that blood found its way inside the silencer by the phenomenon known as draw-back.  This is caused when a gunshot wound is inflicted with the barrel of a gun (or silencer?) in contact with the skin.  Or close contact ie 1mm - 2mm away from the surface of the skin.  When the trigger of a gun is pulled it releases a propellant.  The propellant generates propulsion and moves the bullet, obviously at tremendous speed.  When the propellant is ignited by the release of the trigger it generates hot gases which travel along with the bullet and once outside the end of the guns barrel or silencer will dissipate in the atmosphere.  However when the guns barrel (or silencer?) are in contact with the skin or close contact (1mm - 2mm) the hot gas will be unable to dissipate in the atmosphere so it can be sucked into the wound and then propel backwards into the guns barrel (or silencer?) taking with it blood and often other biological material eg skin tissue, bone fragments from the wound.  As the blood sample found in silencer matched SC's blood type/group the prosecution claim JB shot SC using the silencer and then returned it to the gun cupboard.

There's a plethora of info on the internet and youtube vids explaining the above.  Google how a gun works, how a bullet works, how a silencer works etc.

At JB's 2002 CoA hearing the firearms expert employed by the Home Office, Malcolm Fletcher, told the jury the following:

457. Mr Fletcher, the firearms expert, gave evidence to explain how blood got into the moderator if it was attached, or into the barrel if there was no moderator attached. He said that the mechanism was complicated and not then fully appreciated. However, the expanding gas when the bullet left the muzzle was under normal circumstances distributed into the atmosphere. However with a contact shot there was no opportunity for this escape and the gas would follow the bullet into the wound as it expanded. Back pressure would then build up forcing the gas back out of the wound taking with it blood and tissue which would in effect be blasted back into the barrel if there was no moderator or into the moderator if one was attached. He said that even without direct contact, the same effect might occur but only if the gap between the end of the barrel, or the moderator if attached, and the skin was less than one millimetre. He said that the likelihood of such an occurrence was to an extent dependent on the part of the body to which the shot was delivered and the amount of blood present at that point.

458. If the shot to Shelia Caffell, which was a contact shot to the throat, had been fired without the moderator in place, he would have expected to find blood in the barrel of the gun. If the moderator was attached it was "virtually certain" that Sheila Caffell's blood would get into the moderator. There was, he said "a very slight possibility of it not happening, but very slight".

"Since the blood from inside the sound moderator belonged to the same group as Sheila Caffell, and since there was no blood inside the barrel of the rifle, I was led to the conclusion that Sheila Caffell had been shot whilst the sound moderator was fitted to the rifle."

http://www.homepage-link.to/justice/judgements/Bamber/index.html

At JB's trial the judge, Justice Drake, asked Malcolm Fletcher if there were any other possibilities to account for the blood being in the silencer.  He replied "The only other possibility is that it was put there deliberately".

http://news.google.com/newspapers?nid=2507&dat=19861015&id=E4JDAAAAIBAJ&sjid=q6UMAAAAIBAJ&pg=4879,3440832

However what Malcolm Fletcher overlooked, either out of incompetence or being persuaded to be economical with the truth, is that a silencer reduces the gases ejected with the bullet quite considerably thus reducing the pounds per square inch (psi) from around 3000 psi to 60 psi.  With a silencer fitted to the guns barrel the bullet enters first an expansion chamber and then a number of baffles before it exits.  The expansion chamber and baffles allow the hot gases to expand and slow their release.  Meaning they dissipate in the silencer and the reduced amount that leaves the silencer does so slowly. 

The following animated second image depicts this beautifully 

http://www.industrytap.com/silencer-suppressor-inside-look-one-gun-enthusiasts-coolest-gadgets/26953

Dr Jon Nordby on page 6 states the following

"The draw-back effect can be observed in contact gunshot wounds but the effect(s) of compensators, suppressors and silencing devices as well as any other intervening items may alter the outcome."

http://www.finalanalysisforensics.com/media/pdfs/BasicBloodstainPatternAnalysisTEXT.pdf

This obviously puts a whole different complexion on the draw-back theory in JB's case and the central plank of the prosecution's case.

I think I am right in saying that Ann Eaton's husband, Peter Eaton, was a registered gun dealer.  I wonder if he was familiar with draw-back?    He was the person who handed the silencer to DS Jones having sat up drinking whisky with him 

http://miscarriageofjustice.co/index.php?action=dlattach;topic=3171.0;attach=3580

http://miscarriageofjustice.co/index.php?action=dlattach;topic=3171.0;attach=3582

The victims' samples were handed to EP (see top of page):

http://miscarriageofjustice.co/index.php?topic=204.msg2228#msg2228

Please note that this post has been copied and pasted from the red forum with the posters permission.
« Last Edit: March 04, 2015, 08:36:PM by Patti »

Offline Patti

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 13193
Re: Drawback Analysis
« Reply #1 on: March 04, 2015, 08:35:PM »
This images shows a 98% reduction in hot gases with a silencer fitted.  Thus means that the possibility of drawback with a silencer fitted is rare and very unlikely. 

Offline Jan

  • Hero Member
  • ******
  • Posts: 10318
Re: Drawback Analysis
« Reply #2 on: March 04, 2015, 08:41:PM »
I am annoyed because I found an article which also said the Lab  had made assumptions and there were certain "comparison" tests that had not been carried out. But I am not sure where I read it . I will have a search.

Offline maggie

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 13651
Re: Drawback Analysis
« Reply #3 on: March 04, 2015, 08:57:PM »
This images shows a 98% reduction in hot gases with a silencer fitted.  Thus means that the possibility of drawback with a silencer fitted is rare and very unlikely.
Think this is very interesting, Patti.  Have never trusted the silencer evidence and this certainly reinforces those doubts 100%.
« Last Edit: March 04, 2015, 08:58:PM by maggie »

Offline lookout

  • Hero Member
  • ******
  • Posts: 48670
Re: Drawback Analysis
« Reply #4 on: March 04, 2015, 09:01:PM »
Very interesting Patti. Worth front page news I'd have said. Well at least some sort of circulation.

Offline scipio_usmc

  • Veteran Member
  • *****
  • Posts: 9502
Re: Drawback Analysis
« Reply #5 on: March 04, 2015, 09:13:PM »
Ah today's post on red from Holly.  That post came after a long debate that she lost on these very issues except in her own mind of course.  Proving Holly wrong it easy, it is convicting her to admit you have done so that is a challenge.

Holly took a simplistic generalized claim that attachments and items such as clothing can impact backspatter and drawback and she decided she was going to interpret such as meaning backspatter can't happen and drawback won't occur when a moderator is used. 

Her source stated no such thing though, it is a fact that blood has been found in moderators and thus that drawback occurs in moderators.  Holly said she didn't care and was choosing to interpret it her way.

Gases still escape from a moderator simply the pressure is lesser.  Some moderators have vents so the gases escape from the sides others like the one in this case do not.  All the gases at some point excape through the front. There thus are still gases acting upon the wound.

I pointed out to Holly that backspatter is not only caused by the gases.  That is one distinct cause of backspatter and it happens only when the gun is close enough for the escaping gases to go in the wound (which doesn't just happen with contact wounds the gases still can act upon the wound in non-contact wounds).  I posted 2 other things that cause backspatter and that is even if the gun is far away.  The reason distance matters is because if close enough the spatter will get on/in the weapon.  Drawback is a function of all these things during contact wounds.  I also noted how wounds are much more likely to produce spatter or more significant quantities when there was a previous wound nearby like in the case here where the first wound to Sheila caused hemorraging. 

I repeatedly stressed the most significant thing in whether drawback will occur is looking at the location of the wound and assessing all the relevant issues regarding that location.

Holly didn't care refused to address any of this and decided she is going to pretend her source proves that shots from moderators can't result in drawback.  The bottom line is that Holly's suggestion that blood would not have been able to get in the moderator is wrong as would be any suggestion that it would be unlikely because she didn't look at the relevant factors of location and all the causes of spatter that interact to cause drawback. 

Furthermore she chooses to ignore that they assessed there would have been drawback in the rifle if the moderator was not used.  None of her claims undermine that assertion.  No blood was found in the rifle though as would have to be the case had the rifle been used without the moderator.


 
Politeness is organized indifference- Paul Valéry

Offline Patti

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 13193
Re: Drawback Analysis
« Reply #6 on: March 04, 2015, 09:20:PM »
There is this as well.


Offline scipio_usmc

  • Veteran Member
  • *****
  • Posts: 9502
Re: Drawback Analysis
« Reply #7 on: March 04, 2015, 09:23:PM »
Think this is very interesting, Patti.  Have never trusted the silencer evidence and this certainly reinforces those doubts 100%.

Except that the claim the reduction makes drawback unlikely is not true.  The source doesn't claim that it is simply something Holly (the source of all this) decided on her own.

There are still gases exiting thus acting upon the wound and more than just the gases cause drawback.



Holly was ******** everywhere she could trying to find a source that claims drawback can't occur or is unlikely to occur when a moderator is used but could not find one the best she could come up with was the statement they can "impact" things which failed to discuss how or the degree. 



« Last Edit: March 04, 2015, 09:54:PM by Patti »
Politeness is organized indifference- Paul Valéry

Offline Jan

  • Hero Member
  • ******
  • Posts: 10318
Re: Drawback Analysis
« Reply #8 on: March 04, 2015, 09:32:PM »
if you  are so convinced 100% and so confident why are you so rude about it?

Me thinks you doth protest too much,

Offline Alias

  • Editor
  • Veteran Member
  • *****
  • Posts: 9435
  • What is in those 200 boxes?
Re: Drawback Analysis
« Reply #9 on: March 04, 2015, 09:43:PM »
Kudos to Holly!  ;) ;D

Offline lookout

  • Hero Member
  • ******
  • Posts: 48670
Re: Drawback Analysis
« Reply #10 on: March 04, 2015, 09:52:PM »
if you  are so convinced 100% and so confident why are you so rude about it?

Me thinks you doth protest too much,





It's because he didn't post it. ;D ;D ;D

Offline Patti

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 13193
Re: Drawback Analysis
« Reply #11 on: March 04, 2015, 10:03:PM »
Scip you ignore expert opinions in order to project your own agenda. Now, you question scientists at the highest level.

Having a silencer on a rifle does have an effect on whether drawback occurs, it makes it very unlikely to have occurred, especially as the shot to Sheila was not a direct contact head shot.  The head bleeds profusely, compared to other parts of the body... :-\

« Last Edit: March 04, 2015, 10:06:PM by Patti »

guest2181

  • Guest
Re: Drawback Analysis
« Reply #12 on: March 04, 2015, 10:10:PM »
Scip you ignore expert opinions in order to project your own agenda. Now, you question scientists at the highest level.

Having a silencer on a rifle does have an effect on whether drawback occurs, it makes it very unlikely to have occurred, especially as the shot to Sheila was not a direct contact head shot.  The head bleeds profusely, compared to other parts of the body... :-\

Just out of interest, what agenda could he possibly have?  ???

Offline Caroline

  • Hero Member
  • ******
  • Posts: 27076
Re: Drawback Analysis
« Reply #13 on: March 04, 2015, 10:17:PM »
Scip you ignore expert opinions in order to project your own agenda. Now, you question scientists at the highest level.

Having a silencer on a rifle does have an effect on whether drawback occurs, it makes it very unlikely to have occurred, especially as the shot to Sheila was not a direct contact head shot.  The head bleeds profusely, compared to other parts of the body... :-\

It was also 'expert opinion' that suggested the blood was the result of draw back. Although I don't believe the silencer was used, to argue for or against you have to argue against expert opinion.
Few people have the imagination for reality

Offline scipio_usmc

  • Veteran Member
  • *****
  • Posts: 9502
Re: Drawback Analysis
« Reply #14 on: March 04, 2015, 10:25:PM »
if you  are so convinced 100% and so confident why are you so rude about it?

Me thinks you doth protest too much,

Rude to whom?  Holly? 

Holly is much like Mike.  She has an agenda she wants to push for her own purposes and in order to be able to advance that agenda she seeks out things that she feels she can twist and distort to support her position.  Her agenda is to push her own mental analysis of Sheila's problems which caused her to  commit the murders.  She never met Sheila and there is very little about Sheila publicly available for anyone to be able to try evaluating her mental problems on their own but Holly has decided she knows better than the doctor who treated her and advances her own medical claims.

She can't advance these theories unless Sheila did it so the evidence Sheila didn't do it is an obstacle.  She distorts in order to overcome that obstacle.  The distortions including pretending the only thing that causes drawback are the gases and that the reduction in the pressure of the gases means drawback is won't be deposited in a moderator.  Her sources don't state it is unlikely or impossible she is the one making the claim.

In the meantime unless she finds a source that says it is impossible the argument is a waste of time.  The only way to establish through use of general scientific evidence that the blood can't be drawback and had to be planted is if it is impossible for blood to be deposited in a moderator.

It is rare for drawback to result from 22 caliber wounds to the head.  This is one of the things assassins like because it means they are unlikely to get spatter on them which in turn helps catch them.  Does this mean that if spatter is found that the spatter was planted and can't have actually happened?  No spatter being found is evidence this is one of those rare instances where it happened.   

So what she is engaging in is a complete waste of time and has no ability to disprove the blood was drawback. 

The only inquiry of any value to a defense attorney (and any other Jeremy supporter) would be:

1) to have an expert look for evidence the shot was fired from a distance too far away for backspatter to have gotten so deep inside

2) have an expert look for evidence that even if a contact wound the wound in question would not result in backspatter even if the gun had no moderator

The prosecution argument was two-fold

I. The wound would definitely have resulted in drawback into the weapon had the weapon been fired
without the moderator but none was found therefore a moderator must have been used

II. The moderator had Sheila's blood so was used definitely used
 
Making the argument that it is unlikely for drawback to get in the moderator doesn't help deal with either plank. 

Let's pretend no blood was found in the rifle or the moderator.  The argument that it is unlikely for blood to get in the moderator would be very bad for the defense.  Here is what the prosecution would argue in that instance:

The wound would definitely have resulted in drawback into the weapon had the weapon been fired
without the moderator but none was found therefore a moderator must have been used.  Even though no blood was found int he moderator it is unlikely to get there while it would have to have gotten in the rifle had the rifle been used without it.  So the absence of blood int he rifle proves a moderator was used.

The principal argument which has to be dealt with is the argument the blood would definitely have been in the rifle had it been used without the moderator.

The defense needs to either prove it would not have been likely for blood to get in the rifle had it been used without the moderator or prove blood was found in the rifle by the lab but they lied and claimed they didn't find any.

These are the only ways to get around that particular plank of the prosecution's case.  Even though I pointed it out to Holly many times and to people here it is constantly ignored.

It wasn't ignored by the Court of Appeal they mentioned it again and again in their decision including:

"As to the moderator, there was the remarkable proposition raised by the defence case that Sheila Caffell having killed her family found that she could not shoot herself with the moderator on and instead of simply taking the moderator off and putting it down, went downstairs to an office, put the moderator in its proper place in the gun cupboard and then returned to her parents' bedroom where she sat or lay down on the floor and shot herself. There was in addition not merely the presence of the blood flake in the moderator but the absence of any blood in the barrel of the gun, the end of which would have been in contact with her neck when the shot was fired."

So Jeremy is never going to win an appeal arguing June and Nevill's blood mixed in the moderator then after killing them Sheila put it away in the closet.  Nor is he going to win an appeal by questioning the moderator evidence.

The only way he is winning an appeal is if he establishes one of the following 1)Sheila's blood was found in the rifle but this was concealed or 2) drawback would not be likely to occur from her wound and the blood was planted in the moderator.

That's the only way to prove him to be a victim of a MOJ.


 
 

Politeness is organized indifference- Paul Valéry