Arthur

Someone like Bigtoe will answer this better ...

... but I read many years ago that the 99 was the most efficient HW springer. In the article I read it was saying that there is a formula for working out the size of the cylinder ( or basically the swept volume ) and the muzzle energy that that swept volume produces. The 99 was the most efficient regarding ratio between size of cylinder and muzzle energy ( the article gave figures in % ).

Also, in terms of our 12fp rule ... the 95 is giving it's maximum power at about 15or so fp in 0.22 and probably 14fp in 0.177. So when we run them at 11.5fp they are somewhat crippled and not running at full efficiency. The 99 is pretty much flat out at about 12.5fp in 0.22 and about 11.5fp in 0.177. So we are running the gun at it's full efficiency.

I do agree with some of the comments that with break barrel springers they do normally shoot noticably better in 0.22 than 0.177. The 0.22 system is more efficient, and the same rifle shooting a 0.22 at the same power needs less spring ( so supposedly less recoil ) than when shooting a 0.177.

My Diana 38 break barrel ( I have both 0.22 and 0.177 barrels ) does about 1 to 1 1/2 fp more with the 0.22 barrel fitted. I actually prefer the 0.177 break barrels doing about 10fp for accuracy ( even though I've had this doing 960fps with a light 0.177 pellet ).