Results 21 to 28 of 28
-
September 3rd, 2010, 11:29 PM #21
Re: Why would one file the tip of a bullet?
Mabey his rounds OAL was too long to fit in his box magazine
-
September 3rd, 2010, 11:34 PM #22Grand Member
- Join Date
- Apr 2009
- Location
-
X <-- You are here
- Posts
- 1,640
- Rep Power
- 58781
-
September 3rd, 2010, 11:35 PM #23
Re: Why would one file the tip of a bullet?
in the film he files them down, creates a cavity, and then fills it with mercury
I don't remember why, it was hard enough just staying awake watching the movie.
-
September 4th, 2010, 01:04 AM #24Grand Member
- Join Date
- Apr 2009
- Location
-
X <-- You are here
- Posts
- 1,640
- Rep Power
- 58781
Re: Why would one file the tip of a bullet?
I admit not having seen the movie, and from what has been said so far, I probably won't.
But what in the world would mercury be good for here anyway? This sounds like a really dumb attempt at copying Hardy Krüger using his cyanide tipped cross bow darts in "The Wild Geese".
JanSo long and thanks for all the fish.
-
September 4th, 2010, 01:26 AM #25Junior Member
- Join Date
- Aug 2010
- Location
-
Stewartstown,
Pennsylvania
(York County) - Posts
- 3
- Rep Power
- 0
Re: Why would one file the tip of a bullet?
I would like to start off by saying this is my first post as I am a new member of this forum. I have been reading for a few weeks and decided to finally post. As background I work for the US Army as an aero-ballistic research engineer with concentration mainly in small caliber munitions (up to 40mm).
That being said there are a few reasons why one may file the tip of a bullet many have been mentioned above but offer little explanation so I will start with those and add more as I go.
1. To debur the nose of the projectile – this can be effective but not for the reason many people think. Aerodynamically the difference in the pressure on the nose is minimal, and likely can be ignored barring any very large burrs or flaps of metal being present. The main deleterious effect on accuracy comes from the mass asymmetry that is created this causes an inconsistency in swerving motion that can cause rounds to fly differently.
2. Decrease drag – I believe this was referred to as increasing BC above. This effect of blunting a projectile and decreasing the zero yaw drag coefficient has been well documented from 155mm artillery to 5.56mm ammunition. There is an optimum size of the blunted area of around 12% of the caliber of the round. Drag increases as you move above or below this optimum. Assuming a 0.308” round is deviation of 0.009” will be detrimental to ballistic performance. I doubt that hand filing will lead to that kind of accuracy, however I guess it is at least possible
3. To aid in expansion – if the round started its life as an OTM or FMJ round the nose could be filed down to create a cavity large enough to initiate fragmentation upon impact similar to a hollow point. This would perform fairly well in soft targets at close range while suffering from the above mentioned drag increase.
4. Penetration – This was incorrectly or at least incompletely mentioned above. Sharpening the point of a round will not increase penetration in a soft target. This is often thought of incorrectly as it can and often does increase penetration in hard targets as long as there is little to no obliquity during the impact event. However this is rarely the case, which is why you don’t see razor sharp points on well designed AP rounds. A blunt tip will actually keep a projectile low yaw once it has entered a soft target and due to cavitation it can penetrate deeper than a sharper projectile depending on the velocity.
5. Mercury - the myth about filling a projectile with mercury then sealing it with lead or wax to create an “exploding bullet” has existed in Hollywood for years and has been tested in practice to yield results that are disappointing at best. It can be noted however that the mercury would create a fragmenting poisonous slug that if the projectile did initiate fragmentation would cause a lot of tissue damage as well as make sure the target was incapacitated through the poison ( if enough was left in the system).
Overall it is likely used by the film maker to give the impression that the character knows “secrets” about long range assassinations and must hand craft his projectiles in order to accomplish the objectives of the mission…blah blah blahAero-Ballistic Research Scientist
-
September 4th, 2010, 12:32 PM #26Member
- Join Date
- Jun 2010
- Location
-
Northampton,
Pennsylvania
(Northampton County) - Posts
- 77
- Rep Power
- 78
Re: Why would one file the tip of a bullet?
If Clooney was filling the tips with mercury, he was looking for an "exploding" bullet terminal effect. This "mercury-filled bullet" thing is actually an old standby in Hollywood to ramp up the action, like pistol shots blowing legs off (as in "The Punisher") and the all-time fave, the single shot that blows up the gas tank. In the 1970's movie "The Day of the Jackal" the assassin treats all his projectiles this way to . The incompressability of mercury (theoretically) causes the bullet to, in effect, explode on impact with the target.
There are two problems with this.
First, regarding accuracy, adding a liquid center to a spinning high velocity projectile may destabilize it to the point that it precesses like an out-of-balance washing machine on the spin cycle...and if the filled bullets don't weigh within, say, a tenth of a grain of each other, they won't fly consistantly, also blowing accuracy to hell.
Second, with a home-made exploding bullet like this, there's no way to predict how much penetration will occur before the bullet flies apart. It may perform as expected, or it may blow up at or near the surface, causing a painful but non-lethal crater.
-
September 4th, 2010, 02:06 PM #27
Re: Why would one file the tip of a bullet?
It was also shown in JAWS.
Owner Trigger Time LLc 01 FFL/NFA Saylorsburg, PA. Sales/Service/Transfers/Training
NRA CRSO/Pistol/Rifle/Shotgun inst. BSA Rifle/Shotgun Merit badge counselor. US Navy Marksmanship Team Staff
-
September 4th, 2010, 09:53 PM #28
Re: Why would one file the tip of a bullet?
LOL, I don't disagree with what you're saying about adding mercury to bullets and effects that it might. I disagree with one thing that you and others are saying in this thread. People keep saying "if a bullet isn't within .1 (1/10th) of a grain of each other, accuracy if blown, etc. LOL, have any of you actually weighed every single bullet that you shoot or reload? MOST bullets that people shoot are NOT within a tenth of a grain of each other, or even of the weight that they say it is. Lots of people over the years have NEVER had a problem with accuracy out to 1,000 yards (or further) with Sierra Match King bullets. Lots of people, including the military, do NOT weigh and sort their bullets before loading, and have better accuracy than most people. You'd probably be surprised at the variance in their weight, from lot to lot.
I do weigh sometimes weigh bullets and sort a box by weight in tenths of grains, and over the course of several boxes. I've sat there and helped friends do it, and then sort those further by meplat, ogive lenths, etc. Even on high quality match grade bullets, unless you're talking lathe turned solids, about the BEST that you're going to get on a box of bullets if for them to be a tenth of a grain of what they're supposed to be. We're talking unloaded bullets (not ammo) that are over 40 cents apiece, and 1/10th of a grain is about as good as you can hope for and expect. If you want something closer, you're going to start having to look at lathe turned solids. The other important thing to remember is that weight isn't even close to all that matters, and some people putting way too much important on variation in a tenth of a grain from their weight, when other factors are just as or more important.
In reality, most people don't shoot far enough to notice the difference in a tenth of a grain of variance in bullet weight. Most people don't shoot far enough to notice ANY difference in a tenth of a grain variance in bullet weight. Even people that are shooting long enough to notice a difference, most can't read the wind well enough to notice the different of .1 grain variance in bullet weight. I know that I can't read the wind well enough to notice a difference between say a 190 grain bullet and a 190.1 grain bullet. I can shoot well enough to notice a difference of .1 grains in powder charge, but NOT in bullet weight. For some loads, especially when trying to keep your SD's down on a load, .1 grains of powder can make a difference.
So while I agree with the premise that adding mercury to a bullet could cause it to fly incorrectly, yaw, etc. I think that the variation of .1 grains has almost no effect on the situation. Most people can't shoot well enough to be concerned about bullet run out, .1 powder charges, neck concentricity, neck tension, etc, etc. So I'm sorry, I just don't think that most people will notice any sort of difference in .1 grain difference from one bullet to the next. I hear all the time on this forum about people who's rifles shoot "1 hole", or people that "consistently shoot 1/2 moa groups or better" (sometimes even less than a third or quarter inch). I very rarely hear of those people weighing bullets to see if they're within .1 grains of each other. Go weigh a box of SMK's, which are what Federal Gold Metal Match bullets are loaded with, bet you find a lot more variance than .1 grain.
Similar Threads
-
MPEG-4 file
By AxiTech in forum GeneralReplies: 0Last Post: August 4th, 2009, 05:37 PM -
Convert a .zip file to a .dmt file?
By tes151 in forum GeneralReplies: 0Last Post: February 10th, 2009, 04:06 PM -
Bullet weight vs Bullet length
By Bradster in forum GeneralReplies: 1Last Post: November 25th, 2008, 02:25 PM -
Do you have an FBI file?
By LastManOut in forum GeneralReplies: 25Last Post: April 7th, 2008, 12:38 AM -
Do You Have a Lawyers Name on File??
By Mtbkski in forum GeneralReplies: 14Last Post: July 17th, 2007, 03:06 PM
Bookmarks