Forums › Forums › General Discussion › Getting ready for deer hunting. › Re: Re: Getting ready for deer hunting.
Ericbc7MemberNovember 12, 2019 at 1:00 am21 Bullseyes
No deer yet but interesting observation.
I sighted in the rifle when I got to camp with factory ammo atabout 50 deg f.
Tested the federal 150 grn “whitetail” load out to 461 yds on our steel targets and the “dial up” was 25 clicks on mrad scope. I checked zero day before I left and at about 7deg or less (got down to -3 f) deg f I was almost 5 clicks (5x.1 mrad) low at the same 461 yds. I had no idea that the factory ammo was so temp sensitive.
Check your zeros!
I should expand on this, I plugged numbers into my ballistic calculator and it seems in very cold weather my velocities were close to 300 fps slower than sight in temp. Some powders exhibit considerable temperature sensitivity. Take my results with a grain of salt, I was cold, the rifle and ammo was outside all day so was at ambient temp. I was not using the bench the same way and was different time of day (light). I just mention this to highlight some of the variables involved. I will be going back to cabin in a week or so and hopefully will get a shot at the big one. I’m deffinetly checking the zero when I get back!