Welcome
I got my CZ 527 .17 about a year and half ago and it quickly became of of my favorite centerfires for our local Idaho ground squirrels as well as the larger ones found in northern Nevada.
I have a few favorite loads for my gun. I like 12.2 grains of AA-1680, 12.7 grains of AA-2200, and 12.5 grains of 12.5 grains of CFE BLK all with the 20 grain Vmax and the CCI BR primer. I got one squirrel at 356 yards several months ago but that was with a 20 grain Berger which, alas, they no longer make I don't think. Figures, eh?
The only brass I have is Hornady so that takes care of that. And all the loads that I mention will absolutely group under half and inch at 100 yards with my rifle. I bet you will find something that your gun likes too. I am most pleased with my gun and am chomping at the bit for squirrel season to start again next year.