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foot pounds of energy/joules etc

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dvlnme View Drop Down
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    Posted: 01 Sep 2017 at 7:35am
These are proberly the two lest understood and misused terms used in the firearms and airgun 
 vocablery,niether has any real realevence to how powerful or not a gun actually is but are commonally
 used today to doso.
 Both terms are just a calculation based entirely on projectile weight and velocity and dont take into
 account bore size,what projectile is made of or how it will perform on anything but know size and 
 weight steel plate attached to a ballistic pendulum,which was an early form of chronograph that was 
 starting back in muzzleloading days to calculate velocity.
 Joules is the metric equivelent to foot pounds energy,both are simply calculations of how much energy
 it takes to move a known weight object a certain distance,in case of a ballistic pendlum the object
 moved was a known weight steel plate attached to a pendulum.
 A projectile of known weight was fired at pendulum and distance pendulum moved measured,this measurment then used in the reverse of how its used today to then calculate velocity and then used
 to calibrate gun sights or determine the effective distance a gun was usable out to.
 This was a very complicated time consuming process and mainly used by military arsenals.
 today of course we have modern electronic chronographs to do all these things for us,modern chronos
 havnt been around that long,the first electronic chronos came about proberly in 1960s and were very
 different to those today and due to primative electronics didnt have direct digital readouts we take
 for granted today so were not as accurate as evan a cheap chrono is today and time consuming to use
 There is a little history on foot pounds energy and joules an their reavence to a guns performance etc
 Cheers Mike
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Flub Quote  Post ReplyReply Direct Link To This Post Posted: 02 Sep 2017 at 3:24am
The muzzle energy is still a far better indication of an airguns power than velocity. As we know, some manufacturers quote very high velocities but don't mention that they are using very light pellets that are not much better than plastic bb's when it comes to hitting power. Although muzzle energy varies depending on pellet weight it's only within 10 - 15%, whereas velocity could vary by 100%. Muzzle energy in either fpe or Joules is a meaningful value in its own right, whereas velocity is meaninless without a pellet weight. 

Good to see a bit of history though, especially as I'm old enough to have used a ballistic pendulum and the first electronic chronographs using light sensors. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Pauly5 Quote  Post ReplyReply Direct Link To This Post Posted: 02 Sep 2017 at 11:43pm
Yes, gòod reading.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Novagun Quote  Post ReplyReply Direct Link To This Post Posted: 06 Sep 2017 at 10:22am
This is a topic that I have been following on the GTA forum. It is extremely complicated accompanied by some fairly intricate mathematics. One facet of pellet trajectory overlaps with another facet to the extent that I have to go back and refresh parts of it.
I got to the stage that it doesn't matter a hoot what the science involves as long as it works and it is a bit of a wonder that it does as well as it does.
Even if you grasp all of the technicalities the shooter still has to point the rifle at the right spot to be use.
Then along comes a puff of wind.
Muzzle energy is just one part of it all.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Pauly5 Quote  Post ReplyReply Direct Link To This Post Posted: 06 Sep 2017 at 10:27am
I do wonder how we cope without all this knowledge sometimes. For example all those pigeons must be incredibly unlucky that I hit them without knowing any of that.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote dvlnme Quote  Post ReplyReply Direct Link To This Post Posted: 18 Sep 2017 at 8:02am
Only posted topic out interest,but tiz interesting subject,and one thats interested me for lot years,but 
 its hard to actually define why a projectile specially a small lightweight pellet is so effective,i am 
 continually still amazed just how effective 177 cal pellets really are,my back ground is more in 
 firearms than airguns,was for many years a real lead bullet nutin both handguns n rifles,thats prob why
 i developed a love of airguns,they shoot lead projectiles eh!!
 I posted this topic to get some converstion going on this topic as think there are lot airgun users who 
 have been told lot rubbish bout airgun power etc,and hoping this thread may help some get better 
 understanding on this topic,me i am still trying to figure it out,goin to do some comparision tests using
 a 177 and 22 cal pcp rifles both running at 20 fpe in ballistic gell to see what happens between the two
 Recently seen some tests using 18fpe 177cal using 10.34 jsbs at 50/100yds in gell,still getting large
 wound channels n allmost 300mm penertration at 100yds,bloody amazing,didnt think would be any
 where like that.
 So be interesting to do same tests with both 177/22 at same fpe level and compare.
 Cheers Mike
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Post Options Post Options   Thanks (0) Thanks(0)   Quote nunga Quote  Post ReplyReply Direct Link To This Post Posted: 18 Sep 2017 at 1:06pm
what are you using to make your ballistic gell? ive been interested in making some for a while now but cant seem to find a good recipes that do not require it been chilled in the fridge before use
2nd place HP springer - WFTF World Championships 2014



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Post Options Post Options   Thanks (0) Thanks(0)   Quote dvlnme Quote  Post ReplyReply Direct Link To This Post Posted: 19 Sep 2017 at 7:38pm
Will have dig recipe out,pretty simple,same as fbi use,got recipe off mythbusters years ago,prob still on
 their utube channel.
 Cheers Mike
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Post Options Post Options   Thanks (0) Thanks(0)   Quote dvlnme Quote  Post ReplyReply Direct Link To This Post Posted: 19 Sep 2017 at 7:41pm
Further to that post,coz uses gellitene as base sets faster if chilled a little as made using hot water to
 melt gellitene.
 Cheers Mike
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