Which bit
Bullet speed seems a tad ambitious.
Blimey.
As the bear suggests, if your empties are giving you a stiff bolt lift, on something as small as a Hornet, well, its a classic sign of over pressure (quite bad overpressure as it goes, usual early signs are flattened or cratered primers and the case being burnished by the opening bolt rubbing on the case head).
Your cases are not able to spring back and eject which means the poor little things are not well.
I'm a maggot in another life you know
the Hmr head doesent weight 18 grains quite a bit more
"An infinite number of monkeys banging away at type writers for an infinite period of time will eventually reproduce Hamlet" Thanks to discussion forums we now know this to be untrue.
Um, no one mentioned HMR, which are commonly 17 or 20 gr loads and gets nowhere near your quoted figures (2250ish with a 20gr) using modern powder, ok probably only only 5 gr of powder but smaller cartridge so higher pressure, tripling the powder won't more than double the velocity.
If you're referring to Guesty's post then he is talking .17 hornet, same cartridge as yours necked down and renowned as a bit of a speed demon for capacity, yet it falls 1000 fps short of your reported figure without the wad slowing things down and using modern powder.
Thanks for looking
I'd hazard a guess that the chrono is reading bit's of wadding blown out ahead of the ball
I can manage 3450fps with a nice aerodynamic 30gn from my "K" but that's a compressed load 13.7gn of lil-gun, & under 750fpe