I'm trying something a little different with my newest project. My sample consists of only cold bore velocity readings over a range of environmental temperatures to see how much temperature affects my first shot velocity with RL26 in a 300 WM.
It has been eye opening. For those of you worried about temp swings with RL26, you really shouldn't be. My Berger 215 load has shifted 2 fps with cold bore shots ranging from 28° up to 56° so far.
I've encountered strange POI shifts in the past in different conditions with some of my rifles. I always attributed it to load variance, but for me, it came down to parallax and specifically the rifles with NF NXS scopes. Once I moved away from the NXS, POI shift was no longer a problem.
Thanks for sharing your experiences.I've encountered strange POI shifts in the past in different conditions with some of my rifles. I always attributed it to load variance, but for me, it came down to parallax and specifically the rifles with NF NXS scopes. Once I moved away from the NXS, POI shift was no longer a problem.
I couldn't deny that the POI shifts were real. I was left with the conclusion that it may simply be the nature of the beast. I live in Alaska also, and you know we get some unusual sunlight angles during the winter, with the sun being so low in the sky. Others have expressed their suspicion that differing sun position can cause these minor POI shifts. Some experienced and capable marksmen claim they've experience this when comparing POI from morning to evening shooting events. I wish I knew the cause so I could prevent, or at least minimize, the POI shifts. Dunno...
As it is, I expect some minor POI shifting. I try to shoot my rifles to confirm zero after arriving at my hunt location, shortly before walking in for the spot and stalk hunts so common in the mountain terrain I frequent/hunt. That's the best I can do, until and unless I can otherwise determine the cause and adjust for it.
I have experienced this as well. What scope/s are you using?
Dang! I hope that eliminates any problems related to your scopes.I replaced my NXS with two Vortex AMGs and a March.
Brent, keep us posted on temp swings above 80°.
Interesting. My hunting rifles have March 2.5x25x52, and two Huskemaw 5x20x50's. My PRS rifles have Vortex AMG and NF ATACR/F1. These all have "fast ratio" parallax/focus turrets in common, and I experience no zero shifts with these scopes.I replaced my NXS scopes with two Vortex AMGs and a March.
Personally I would have a hard time with varying cold bore shots and poi shift and not have the shooter come into play. It happens to me for archery as well. Always better when you warm up. After you get some shots down range, do you find yourself adjusting your scope back to where you started?