Groups Opening Up

[slipper 116]

Went out friday to test some homeloads, was all ok to 150 yards, but when I shot out to 200 they were opening up a fair bit, I use 40grn vmax with the maximum load of 27.8 grains of powder, and the rifle is a cz 527 223

[dicehorn 38]

Slipper - If you have not changed your cartridge recipe (powder/primer/bullet make or primer) it could just be that 'you had a bad day'. Have another go and things may turn out differently. Also bear in mind that we have and continue to have quite windy days and whilst it may not make too much difference at 100 yds, at 200 yds in wind, your groups could open quite considerably.

[yellowdog 12]

It can be many things not least the shooter having a bad day. Check your gun is cleaned correctly, mounts and action screws tight etc. Wind becomes much more apparent the further out you get as does shot to shot speed variations. Sometimes a load don't perform brilliant at 100 yards but actually produces stunning long range accuracy, the reverse can also be true (in fact more often it is most frequent). The reasons for this last point are often said to be stabilisation and with 40 grns out of your CZ (these have different twist rates in the range) could well be the reason or at least some of it. Think about it the rate of twist has to relate to the speed of the bullet and it will be slowing more markedly at 200 than it did at 100