I don't know, but as a kid I used to pump my model 66 20 times and I could swear that this turned it into a sniper rifle.
Amazon has one that can enter outer space.... no wait, my bad... that's the owner that has one.
That's why I like old threads. It's fun and informative to occasionally bring them back for a refresh with new ideas and data.I might try a lead BB in my recently acquired Mod125-177. I recall buying some Gamo lead 177 BBs a few years back but never really had a use for them. At 4.5mm they should not fall back into the 4mm transfer port. The Gamo round balls according to their website are ~8.2 grains. Will post back here with chronograph results if I can find those BBs. I have Daisy and Crosman steel BB's (5.2 grains?) left over from my childhood airgun days (1970s) but am not going to shoot them through a Mod125... even if there is no chance of damage to the rifling. I'm more concerned with rebounds and ricochets from my steel trap.Some 7.8 grain round nose pellets are averaging 1237 fps in that rifle so a lighter steel BB should reach/pass 1500 fps. I would not expect to get consistent accuracy with any BBs at supersonic muzzle velocities.