Was shooting long today with a fellow who wanted to learn some basics. We established drops at 5,6 and 700 yards for his .308 Win. Rem. M-700 VS. Load is 46 gr. Varget, 165 gr. Nosler Ballistic Tips, not sure about case or primer. Scope was a 6.5-20 Leupold set on 20.
Rifle shot well, had some three-shot groups around .5 moa. Five above zero C, winds were 6-8 mph from 11.30. His ammo was reloaded, not sure how many times for the brass used initially. He ran out of the stuff that had been reloaded, switched to reloads with new unfired brass. Shot at 100 yards and he hit into a previous group.
Why did the 500 yard zero change two minutes? Checked and rechecked - this is what the rifle and load did. How can the zero go out two minutes at 500 and virtually back to what we had originally at 6 and 700? Only variable was the unfired brass. Accuracy remained impressive, he had some very good 3-shot clusters at each range.
Pretty confident this took place as described but not sure why.
Been there done that, gave up trying to figure it out. [img]/ubbthreads/images/graemlins/crazy.gif[/img]
As Michael says: "Because any other sport just would not be frustrating enough!!"
Actually, my problem was terrain. A swale about 3/4 downrange, when the wind was from the right direction and up towards 10 mph, I got a rise in POI but the POI was consistently high from there on out.
Your experience violates someone's law about something.
I may be the slowest guy on the mountain . . . . but . . . . I'm on the mountain!
The scope tracked really well, returned to zero perfectly. I really doubt the problem was the scope, it was properly installed and mounts tight. Definitely defies some law of ballistics, not sure which one or how many but has me beat.
Ian, if the wind was from 11:30 (nearly head-on) as you said, he might've shot his fireformed 3-shot group in a gust, causing it to require more elevation. It doesn't take long to put three shots downrange, even less for a wind condition to change. Did ya'll note a stronger gust about that time? It is curious since the others were pretty close to the original ...... [img]/ubbthreads/images/graemlins/confused.gif[/img]