Thread: Testing loads at 50m instead of 100m

Greetings All,
An interesting discussion. I do most of my chronographing and initial load development at 60 metres as this is convenient here. Final zero and testing is done at 108, 172 or 198 metres depending on the rifle and its capabilities. The odd ranges are due to the availability of a bench and backstop at these ranges. We all have an idea of the range that we are competent to shoot at and my belief is that we should validate our trajectory by test firing out to at least 2/3 of that range. The mesage here is that do not zero at 50 metres and pretend you know where your projectile is going at 300 let alone 500 metres. As for groups tightening at 200 metres from 100 metres when measured in moa or mrads I have seen this too often for it to just be chance. One of the factors here may be parallax or the apparent shift of the reticle due to head position. Non adjustable scpoes will have some parallax shift at 100 metres and more at 50 metres.
Regards Grandpamac.