FPS

[Guest]

I wanted to ask knowledgeable people that the advertised feet per second of a particular air rifle, is this speed the average speed? Or is it the maximum speed that the air rifle can achieve under perfect conditions, such as perfect visibility, no wind, perfect pellet etc.

[Comp]

.... Think you will find it is the speed the pellet is chrono'd at,... usually as it exits the barrel........ or shortly after,.. depending on the chrono used....

 

Cheers, Fred

[Guest]

Oh ok, so this speed that the pellet is chronod at, for example if they advertise an air rifle as having 600fps, will the pellet be propelled at 600 fps every time or be subject to like: pellet size, wind speed etc.?

Or does it indicate an average speed that the pellet is propelled at, so sometimes it might do like 620fps for example.

[Beardo]

there will always be some variation between shots, the better quality rifle/pellet the less variation generally.

different weight pellets will travel at different FPS

Edited December 9, 2008 by nickbeardo

[stevethevanman]

Wel know, what is advertised will usually be stating that their rifle does thowr pellets out at say 600fps, but...with air pellets because their so small, pellet design has very little impact on velocity I imagine. But the best way to find the average velocity of your gun, would be to fire it, record it, fire it, record it, fire it...record, ect...

 

But 5 times is not enough, the more trials ran, you will increase the accuracy of your average. So a hundred averages may be nesscary to get a very accurate average.

 

Steve

[southernlad]

The FPS quoted by the manufacturer is based on a chronographed reading at a set distance (very close, can't remember the exact distance! :( ) from the muzzle using whichever pellet they find performs the best I believe. it will be an average from a number of the same type of pellets fired.

 

Pellet weight and shape can have a serious effect on velocity, often to the point that your air rifle may be producing more than the legal 12ft lbs.

 

If it concerns you get your rifle chronoed with a selection of different pellets. The majority of good quality hunting rifles will be tuned to output at around 11.5 ft lbs to take into account the possibility of some pellets producing higher velocities than others.

 

There are other factors to consider also, even with the same type of pellets used such as manufacturing defects, distortion from handling, dirt etc. I wouldn't lose too much sleep over it though! Just find a pellet that is consistently accurate in your rifle, select well formed pellets, discard any odd ones, keep them clean and treat them gently.

 

Hope that helps'

 

 

cheers

 

SL