CZ triggers have a break in period. Don't even bother with the set trigger (awful) but the single trigger can be set down to a good hunting weight and will smooth up -and get better- with use. I had to adjust both my Hornet and my 204. After a couple of hundred rounds they lost the gritty feeling. That suggested, Timney makes one for the CZ 550 which is said also fits the 527~Muir