I'm no expert either, but a friend of mine has hunted with airrifles for some time and he's kinda got me into it...
I think this was mentioned above somewhere, but the 177 has a very flat trajectory and a much higher velocity, whereas the 22 actually travels in a arc and as far as I understand it requires more setting up and greater judgment of distance to target depending on how you zero your scope, BUT, and please correct me somebody (RapidBoy!) if I'm wrong, but the 22 packs a much bigger punch and I've heard (only heard!) that 177 due to its smaller impact and greater velocity often passes straight through a small soft target causing terrible wounds that might not be instantly fatal, meaning that the rabbit for example, might run off somewhere and die a painful death where you can't even get to it. This I believe (from the same source!) can be rectified somewhat from by the use of hollowpoint pellets.
If you look around you can often see tests where a 177 and a 22 have been shot in controlled conditions into the same large block of soap and you can clearly see what a difference the 22 makes, i.e. it has a final impact zone creating a large hole (compared to the pellet size) much like a real firearm does when it expends all its energy on impact, whereas the 177 travels much further through the soap in a straight tunnel and ends compacted in by the soap.
This is all from a guy I sit next to at work that I've become quite chummy with who hunts rabbits on a regular basis with a 22 with some success and I own an Airarms S310 which I am very pleased with, but very rarely get a chance to do much with.
I guess the key whatever you choose is that you need to be confident that when you take aim and pull the trigger that you are going to put down what you are aiming at and not just maim it or give the target a mortal wound that will prolong its suffering in some hole somewhere. This takes practice and confidence in your rifle and ihow well you've set it up.
Geoff
a 22 pellet and a 177 pellet start of with the same energy at the muzzle ie 12ft lbs
as they travel they slow down due to friction in the air and as they do they lose energy
the lighter 177 pellet will slow quicker so on impact at say 30yrds will have less energy
the difference isnt that great at normal hunting ranges
but the energy is concentrated in a smaller area so will penetrate further on 177 than a 22 ( assuming the same head shape ie domed and similer % mass )
and is any projectile passed throu teh target it will not have passed all its avalible energy into the target ( as its still moving it cannot have done) so over penetration could be a problem
However at 12 ft lbs your only sensible kill zone is a brain shot which in a rabbit (your bigger quarry) is 1" dia ish or 25mm if you compare the pellet sizes to this you will see either is large and will kill cleanly if you hit it. Its been said you only need 3ft lbs impact energy to kill a rabbit and a good round head 177 pellet retains this out to 100yrds from a 12ft lb start.
Knock down power is a myth ( the bad guy is only put thro a window 6 ft behind him from a 44 magnum to the chest in the movies )
close up yes a 177 is more likly to go thro than a 22 this i have found only in close qtr ratting on small rats or on head shot pigions which a 22 would go thro anyway
Conclusion (valid for sub 12ft lbs airguns only
FAC ones is 22 cal)
Best option is 177 as its capable of a clean kill at more range than you can shoot it and because accuracy of shot placemnt is more important for this type of gun The 177 wins hands down because its far more forgiving for rangefinding at allranges (this is why its the cal of choice for FT )
for all genreral hunting use the most accurate pellet in yout gun this will more likly be a domed head i nthe 8.4 grain weight
if you do go ratting and do find a over penetration that is a problem try a flat head pellet
if you have 22 or want 22 its not a problem if your happy and can hit your target at teh end of the day thats what counts
ATB
Duncan
