Question about POI shift

[EchoDeltaSierra]

I was at the range today with a new rifle and testing a few different varieties of ammo shooting at the 1" dot-drill target. What I was most surprised with was my first 20 rounds were 168 gr. HPBT PPU match grade, I then switched to Federal Match Grade in 168 and 175 gr. My first two shots of Federal had almost a 1/2 mil shift in point of impact. It was easy to adjust the scope and shoot the next 18 rounds accurately (or should I say accurately enough, when I did my part). I was surprised to see a shift that significant. Have others experienced that?

Thanks.

 

[varmint slayer]

.5 mil which way?

 

[sjb269]

Short answer, yes.
many variables between ammo types.
Other than gathering data, best not to switch ammo type until all of that lot/supply is expended, then switch brand/lot and re-zero. Hopefully you didn't pass up an opportunity to log the POI changes from brand X to brand Y...that's useful info.

 

[EchoDeltaSierra]

Short answer, yes.
many variables between ammo types.
Other than gathering data, best not to switch ammo type until all of that lot/supply is expended, then switch brand/lot and re-zero. Hopefully you didn't pass up an opportunity to log the POI changes from brand X to brand Y...that's useful info.

Totally logged that stuff. To break in the gun, I've been running a variety of ammo through it and observing / recording the results. Fascinating experimentation.

 

[EchoDeltaSierra]

.5 mil which way?

The shots moved .5 to the left. I fired the first round, looked, laughed at how bad I just sucked at that shot, then shot again and produced an identical result. I adjusted my optic and shot the next 18 rounds on target.

Stuff like this makes me really appreciate the H59 reticle I was talked into.