Does anyone have any experience shooting bullets heavier than 55 grains out of a 22 Hornet? My old Hornady book has info for 55 grainers but I haven't been able to find any thing heavier.

cfore,
The main problem with your idea is that the 55-grain bullets are too long for the rifling to stabilize the bullet in flight.
Most Hornets have 1 in 16" rifling. Rugers have 1 in 14" rifling. Using the Greenhill formula, the ideal rifling twist for a Sierra 1410 HPBT-Match bullet of 52 grains is 1 in 10.5". The best rifling for a Sierra 1330 Spitzer of 50 grains is 1 in 11".
That being said, I can give you some results for 50 to 53 grain bullets. I'll give best results, but in reading over my data I've found these results to be very erratic... some very good groups (5 shots @ 100 yards), and some "patterns".
Hornady 2250 HP Match (53 grains), 9.0 grains of H4227, CCI #400 primer, W-W case, 0.75".
Same bullet, case & primer, with 9.4 grains of H110, 1.25".
Sierra 1410 HPBT-Match (52 grains), 12.5 grains of Hodgdon's Lil'Gun, Federal #100 primer, W-W case, 0.625".
Sierra 1330 Spitzer (50 grains), 11.6 grains of W296, WSR primer, R-P case, 0.625". BE VERY CAREFUL WITH THIS LOAD!!! This makes a BIG bang, and can result in blown primers and stuck bolts!
I tried these loads in a Ruger 77/22VHZ, with a 24" barrel and 1 in 14" twist. All bullets were seated .020" off the rifling.
I recommend you use Hodgdon's Lil'Gun, because you won't get dangerous pressures, even filling the case all the way up. If you start mixing heavy bullets in a little case with H110 or W296, it's very easy to generate exceedingly high pressures. I can't overstate the hazards involved!
Regards, George.

Thanks for the information.