heavier the pellet

[Sterry 0]

I've worked out both of the two formula using just imagined figures.

 

presuming that: FPS = 500 (i presume this is the scale of velocity that others talk about)

Pellet mass = 16 grains (also guessing this is the measurement)

 

*(squared)

 

FPS* X Mass

___________ = 8.8841506 ft/lbs

 

450240

 

 

 

 

the other

 

FPS*

__________ X2.222 X Mass = 8.888(reoccuring)

 

1,000,000

 

 

 

seems too close so i guess both work especially as its said 450240 is generaly used (suggesting its a decimal that would make up the difference)

 

Just seem that the first is a the wide spread formula so i presume the standard that the police would use. (its easier to work out as well) No doubt its origins are from america and has over tacken those methods of us lil brits way of doin things like you friend at Holland & Holland.

 

Didnt mean to offend Masmiffy, just seemed bit strange formula all things considered. ( Knew i wasnt cut out for this A-level maths lark)

 

 

 

To test this wouldnt you need 2 rifles (one PCP one spring) running at exactly the same Ft/lbs with a standard pellet. (impossible without a fully adjustable PCP and if you can find a spring that performs eactly the same time after time) Then test an array of pellets with the same aerodynamics to cut out any possibility of effecting results. Not very likely i shouldnt think.

 

Just keep yourself open to theories of how and why and pick the most plausable. or just except as part of life.

 

 

 

sorry for the MEGA LONG post!

[Deker 3,450]

A springer delivers its air almost instantly and its hot air after @7 inches thats it ,its reached its maximum fps ..after that it slows.Thats why springers as a whole have shorter barrells..A PCP delivers cold air and it accelarates the full length of the barrell .Put a longer barrell on a PCP and performance inproves the opposite in a springer...If in doubt dont argue try for youself.

 

 

Chap...wether it be regulated or not a PCP has its maximum power at the instant the air is released, not at the end of the barrel, the power drops the further the air travels down the barrel...just like a springer!!

 

And whether the barrel be long or short on either, the power can be adjusted to 12ft lb regardless. There are plenty of short barrelled PCP's running at 12ft lb!!

 

How does this explain light pellets being more powerful in springers and heavy pellets being more powerful in PCP!!

[chimp 299]

taken off another site

 

 

 

A heavier pellet travels slower so the blast of air that accelerates it does not need to move as quickly. Air has mass so the faster the air travels, the more of the total potential energy available is wasted by accelerating the air itself. This is why heavier pellets are more efficient. This should be true for springers too.

 

I reckon in spring guns however the energy and efficiency is much more to do with the fit of the pellet. How long it takes the initial blast of air to start the pellet moving in the barrel is the most important factor in this. A spring gun would be theoretically at its most efficient if the piston comes completely to rest at the end without bouncing back at all, having imparted all its energy to the pellet in one pulse. In the real world this must be very rare, requiring the spring rate, piston weight, friction of piston seal, transfer port and actual pellet size and weight to be totally in harmony... man.

 

 

and

 

 

 

The heavy pellet travels slower, so it spends longer in the barrel, so has more time to absorb energy from the air blast.

 

However, in a spring gun, the heavy pellet causes additional resistance to the piston, which may bounce back slightly on the compressed air in front of it, dropping the air pressure behind the pellet.

Also, the heavier pellet takes longer to accelerate, so, again, there is more potential for the piston to bounce backwards and lower the air pressure behind the pellet. A light, fast pellet is gone from the barrel much more quickly and gets moving form the breech much more easily, so there's less time for piston bounce to have an effect.

 

 

 

and

 

 

Air in PCP's is compressed to a high pressure, therefore it is continuously expanding and pushing in the barrel. The air in a springers is just a short pulse, and just gives a short, sharp shove to the pellet

 

 

and

 

 

Bismags (and the very similar H&N Baracuda/Beeman Kodiak) have thick, hard skirts that are designed to withstand FAC airgun blasts without the pellets being shredded. At 12ftlb, the skirt is too thick and hard, so tend to resist the air blast driving it through the rifling and the choke and so the gun expends energy just to get the pellet moving.

 

But if you tested every pellety on the market, you would find that there is a general trend for heavier pellets to give higher energy in PCP's and lighter pellets to give higher energy in springers/rammers.

But it is just a general guide. Pellet fit in the barrel also plays an important part.

 

 

 

but like what has been said if in doubt try it yourself . i did

[donnyc 1,203]

Rubbish if you fit a longer barrell to your pcp it will be more efficient and better fps ..Why do you think hundreds and hundreds of rapid owners bought their BSA match barrells from me .end of instead of arguing as I said stick a bismag in a springer and watch the power reduce.Then put an accupell in watch it go up..within its range that is.Your argument doesnt hold water whats the average barrell length on a springer??ditto for PCP..??One uses forced air that is hot air the other uses stored air that is cold

[redeye jedi 39]

well done donnyc was wondering how long it took for someone to realise its the way the power is produced.

[donnyc 1,203]

Rubbish if you fit a longer barrell to your pcp it will be more efficient and better fps ..Why do you think hundreds and hundreds of rapid owners bought their BSA match barrells from me .end of instead of arguing as I said stick a bismag in a springer and watch the power reduce.Then put an accupell in watch it go up..within its range that is.Your argument doesnt hold water whats the average barrell length on a springer??ditto for PCP..??One uses forced air that is hot air the other uses stored air that is cold

If you need to see it with your own eyes Come to mine and have a demo..

[chimp 299]

donny i dont know why it does it but have tested it myself ,they where other peoples theorys .

 

only one who needs convincing is deker

[clubshot 22]

Interesting Coments

 

Check out Fluffybucks report's on most Forums - airgunbbs - airgunforum

 

We made a 21.00 Grain Piledriver in .177 - with a Boatail

We really mucks up most report's of pellet weights

 

Was made for Markets where high power Air Guns are used but restricted to .177 Calibre

 

BOB/R

[donnyc 1,203]

Interesting Coments

 

Check out Fluffybucks report's on most Forums - airgunbbs - airgunforum

 

We made a 21.00 Grain Piledriver in .177 - with a Boatail

We really mucks up most report's of pellet weights

 

Was made for Markets where high power Air Guns are used but restricted to .177 Calibre

 

BOB/R

Are they accurate Bob?? What range did you test them at in the factory//

[Deker 3,450]

donny i dont know why it does it but have tested it myself ,they where other peoples theorys .

 

only one who needs convincing is deker

 

 

Chap..

 

All we have here is a mutual back slapping excercise ...... I did this, my mate did that, we tried this, someone told me that...and now it is apparently accepted truth..there is NO science here, and yes...like for like I am not convinced at all. My experience says this does not make sense, but I am happy to be proved wrong if you can show me something more than a backyard test of 2 rifles!

 

There are far too many variables, nobody has properly sized pellets and barrel, hot and cold air from springers and PCP... bull***t...compress air and it gets hot, barrel efficiency, length, quality, condition, seal integrity, etc, etc.....if you want to believe it fine, but show me one bit of anything close to science to prove it!

 

Until then I remain unconvinced...and so should you...

 

Happy New Year!!

[donnyc 1,203]

sad .A known fact in the airgun world ask any good airgun manufacturer or gunsmith ..If you cannot grasp it its a no no ?? ..In a PCP you are not compressing it as such in a springer you are hence swept volume

donny i dont know why it does it but have tested it myself ,they where other peoples theorys .

 

only one who needs convincing is deker

 

 

Chap..

 

All we have here is a mutual back slapping excercise ...... I did this, my mate did that, we tried this, someone told me that...and now it is apparently accepted truth..there is NO science here, and yes...like for like I am not convinced at all. My experience says this does not make sense, but I am happy to be proved wrong if you can show me something more than a backyard test of 2 rifles!

 

There are far too many variables, nobody has properly sized pellets and barrel, hot and cold air from springers and PCP... bull***t...compress air and it gets hot, barrel efficiency, length, quality, condition, seal integrity, etc, etc.....if you want to believe it fine, but show me one bit of anything close to science to prove it!

 

Until then I remain unconvinced...and so should you...

 

Happy New Year!!

[Deker 3,450]

sad .A known fact in the airgun world ask any good airgun manufacturer or gunsmith ..If you cannot grasp it its a no no ?? ..In a PCP you are not compressing it as such in a springer you are hence swept volume

donny i dont know why it does it but have tested it myself ,they where other peoples theorys .

 

only one who needs convincing is deker

 

 

Chap..

 

All we have here is a mutual back slapping excercise ...... I did this, my mate did that, we tried this, someone told me that...and now it is apparently accepted truth..there is NO science here, and yes...like for like I am not convinced at all. My experience says this does not make sense, but I am happy to be proved wrong if you can show me something more than a backyard test of 2 rifles!

 

There are far too many variables, nobody has properly sized pellets and barrel, hot and cold air from springers and PCP... bull***t...compress air and it gets hot, barrel efficiency, length, quality, condition, seal integrity, etc, etc.....if you want to believe it fine, but show me one bit of anything close to science to prove it!

 

Until then I remain unconvinced...and so should you...

 

Happy New Year!!

 

Chap..All we have here is a mutual back slapping excercise ...... I did this, my mate did that, we tried this, someone told me that...and now it is apparently accepted truth..there is NO science here, and yes...like for like I am not convinced at all. My experience says this does not make sense, but I am happy to be proved wrong if you can show me something more than a backyard test of 2 rifles!

 

Like I say, point me in the direction of some science...if it is a known fact in the airgun world that should be easy... it does not interest me how many think this is the case...I am not convinced, and I don't care if I am the only one, show me the science behind this known fact and I will accept it

 

I can find nothing on the web to substantiate this...just a load of debate and suggestion on forums by those wanting it to be the case, all I ask...show me the science!!

Edited December 28, 2008 by Deker

[chimp 299]

instead of asking for proof why dont you try it yourself and maybe you could shed some light on it as i will put my hands up and say i dont know why it does it , it just does

[masmiffy 82]

No offence taken sterry.

I knew the gunsmith who gave me the 'formula' wouldnt be wrong his father was a ballistician!

I know the old chap had connections in USA so guess its where it originated from?

Strange how this works the pellet weight to ft/lb.

I do know that Titan and now Falcon set their guns using Bisley magnums to be legal.

Must be a reason for it?

 

Incidentally I believe there are only 3 pellets the police can use for testing air guns?

Chap at Falcon told me this!

Edited December 29, 2008 by masmiffy

[donnyc 1,203]

sad .A known fact in the airgun world ask any good airgun manufacturer or gunsmith ..If you cannot grasp it its a no no ?? ..In a PCP you are not compressing it as such in a springer you are hence swept volume

donny i dont know why it does it but have tested it myself ,they where other peoples theorys .

 

only one who needs convincing is deker

 

 

Chap..

 

All we have here is a mutual back slapping excercise ...... I did this, my mate did that, we tried this, someone told me that...and now it is apparently accepted truth..there is NO science here, and yes...like for like I am not convinced at all. My experience says this does not make sense, but I am happy to be proved wrong if you can show me something more than a backyard test of 2 rifles!

 

There are far too many variables, nobody has properly sized pellets and barrel, hot and cold air from springers and PCP... bull***t...compress air and it gets hot, barrel efficiency, length, quality, condition, seal integrity, etc, etc.....if you want to believe it fine, but show me one bit of anything close to science to prove it!

 

Until then I remain unconvinced...and so should you...

 

Happy New Year!!

 

Chap..All we have here is a mutual back slapping excercise ...... I did this, my mate did that, we tried this, someone told me that...and now it is apparently accepted truth..there is NO science here, and yes...like for like I am not convinced at all. My experience says this does not make sense, but I am happy to be proved wrong if you can show me something more than a backyard test of 2 rifles!

 

Like I say, point me in the direction of some science...if it is a known fact in the airgun world that should be easy... it does not interest me how many think this is the case...I am not convinced, and I don't care if I am the only one, show me the science behind this known fact and I will accept it

 

I can find nothing on the web to substantiate this...just a load of debate and suggestion on forums by those wanting it to be the case, all I ask...show me the science!!

Not slapping no feckers back done enought tests to prove its correct.Not on a couple more a couple of hundred known fact to many many people,,, just accept the truth its out there .Oh Bob you never replied to my question