tailwind mirage 270win

[dirtysanchez]

hey,
im a newish to the long range game. thanks in advance for any comments/suggestions.

im working up my skills from being seasoned a 0-300m hunter to something more of a 500m shooter with my tried and tested rig.

22"barrel weatherby vanguard, boyds thumbhole stock bedded floated wearing a leupy vari 1 2-7x33 (simple but effective!)
shooting factory 130gr rem corelokt protected points.
this combo usually shoots .25MOA groups sighted 200yd zero, (usually can 3 leaf clover on a dime at 200gun))
the other day i did a range session 10mph 6oclock tailwind, hot day 85deg and a dancing vertical mirage.
my 100 group was about right 1.5" high, 200 group was tight but 3" low, my 300 group also tight but was even lower 15"low !
i reshot the groups several time over a couple of hours, a new one on me?
i was working my way out to 400-500, but couldnt get past the wildly low trajectory i was experiencing.

could this be tailwind mirage, or a horizontal parralex error effect from my cheeck position on my stock?
other suspect is a new batch of factory rounds being alarmingly cooler than they should be ?
open for suggestion.

 

[benchracer]

First off, by the sound of things, I think you are shooting pretty well in mirage conditions. Mirage always makes my shooting go to hell in a hand basket!

Personally, I am just starting to work on learning to handle mirage. In my limited experience so far, mirage typically makes me miss high, in addition to playing havoc with my wind calls.

The fact that your groups are staying tight makes me think that your trajectory problem is not mirage related. Given that your POI @ 100 is about right, I would tend to suspect your "new batch" of ammo. Even so, 5 MOA low at 300 seems like excessive drop even if your ammo is a LOT slower than normal.

Are you shooting the same bullet and the same weight as before?

Though parallax can contribute to shooting error at long range, I don't think a simple parallax error would come close to 15" @ 300 yards.

 

[telehead1]

I also shoot a vanguard in .270 and have had similar experiences with 150 and 130 grain corelock remingtons. For factory ammo it doesnt get much worse, at least not that Ive found. They can be very inconsistent in accuracy as well as performance on critters. I stopped buying them a few years back after a 150 did not exit a smallish mulie at 70 yards. I found the bullet mostly intact against the skin on what should have been the exit side. For (relatively)cheap factory ammo to just sling lead downrange without going for super-tight groups at least step it up to federal premium or lower end hornady. At least thats what I do when i just want to blow off steam.