What I meant was, if you fire a 6gr pellet at say 800fps it has 12ft/lb energy. If i put a bigger pellet in the rifle and it came out at 800fps it would have 30ft/lb energy, obviously the bigger pellet will travel slower than the lighter pellet so is there any way to calc its energy other than chronographing the gun?

It's like this matey.

The rifle develops the power, not the pellet - ignore the advertising hype.

Your rifle has a limit to the power it can provide to push the pellet up the barrel.

Fact : Your rifle will be able to push a lighter pellet up the barrel faster than a heavier pellet.

Use this as an example - Try throwing a tennis ball - it goes a long way - yes ? Now try throwing a house brick - not so far eh ?. It's the same with air rifles (unless they are modifed).

Light pellet = more fps than a heavier pellet but the ft lbs remains the same (or there abouts). It's a mathematical fact. I've been there - done that - trust me, I've tested them all.

Just buy sensible standard top of the range pellets RWS, Premier, Air Arms - ignore the so called 'super magnum' pellets.

Good quality, accurate pellets are what you need.

Good shooting - webmaster.

What is your main interest. f4bscale magic website

amen to webmaster , but RWS are ok, i've had them for ages, but logun penetrators really are incredible (not for the squeamish though if you are shooting game)