I have not chronied my jet, but the powder (I-4227) and charge weight is very simiilar to what I'm using in my 218 BEE, about 12.8 grains in the BEE with a 40-gn vmax.
The BEE clocks at 2950fps with this load, which is very hot. I shoot it in my Ruger #1 and my Marlin lever. I chronied it in an older (pre-NEF) hornet that I'd had punched out to 218. It got kinda sloppy after about 2000 rounds, I didn't know about shimming ang feeler-gauging so when Marcus said he wanted it for a project, I sold it.
I'm using 12.? grains with a 35gn vmax. I'd hafta look to see exactly how much but I'm guessing the velocity is well over 2500fps. It's definately more gun than the hornet.
12.8/40gn/218BEE is a max load, I re-work it every time I get a new lot of powder (which ain't often since an 8-pound keg goes a looong way).
I have not slugged the bore but it's working fine with .224 dia.bullets--they'd swage down easily anyway if the bore was .222, which I'm pretty sure it is not.