Inconsistent Rear Bag - High POI ???

[ForgivenAll]

Gents, I think I just stumbled across a problem that I was trying to solve shooting prone with high point-of-impacts as the range increased. I noticed at 300-400 yards I was about .1 or .2 high and about .5 mil high at 800ish. Now I'm looking on how to consistently FIX it.

Background:
Rifle: 6Dasher, 107 SMK @ 2960 FPS, 3.7 SD, ORH groups (3/8" ish), Lapua brass, CCI450, Kreiger M24 Contour @ 26", Bighorn Origin, Bushnell XRS, Atlas Bipod, Gamechanger rear bag, suppressed or brake
Experience: Unfortunately, a lot of self-training. Looking to get into one of Frank's fundamentals class. Been competing in 1 or 2 national PRS/NRL matches / year for the past 3 years; over the past two years I've probably shot 8-10 local PRS/NRL style 100 rd matches. Placing about mid-pack of recent national matches and about 10-15th out of 50-60 for local matches. So, LOTS OF ROOM FOR IMPROVEMENT, but understand how to play the game.

Problem: I start shooting day 1 of the Bighorn Steel Classic. The first several stages in a row are prone and I notice I'm making solid hits but start shooting high as the distance increases. Phil Velayo was in my squad and I asked if he'd watch my impacts. At the 800 yard IPSC, he said, "hitting high in the shoulder". I told him I aimed low to make that hit. (Measuring w/ the reticle, I had to aim .5 mil low) So, I started incorporating this in to my firing solutions where I'd back out a tenth here a few tenths there and finished about 50% of the pack.

Now, I'm back home doing a little practicing in the wind but I noticed occasionally I was hitting dead on elevation and OH WOW whenever I hit high (like about .6-.7 mil at 975 yards) I found my reticle had jumped after firing! Meaning, I had to move the rear of my rifle stock up so I could watch for impacts.

My shooting positioning:

• I'm trying to load my bipod in the dirt by leaning into the stock
• I've got my Atlas bipod legs up a notch or two so I'm up on my elbows and square behind the rifle
• I use my gamechanger as a rear-bag when shooting prone like this (I used to put my stock in the V when I was laying down too close to the ground), now I find I place the toe area of my Manners T4A on an 'ear' of the gamechanger
• I could sometimes connect each time at 975 on my 9x12 plate and then I'd get a high impact, so I'm not doing something consistent enough

Questions:

• How do I tell if it is a stock positioning/fitting issue?
• What can I try with my bags to make the rifle come straight back like it would if I wasn't behind it?
• What questions should I be asking that I don't know I should be asking?

 

[msstate56]

The last two matches- I’ve noticed a trend of hitting high. Myself- I’ve got a rifle and ammo combo with dope verified out to 1000 yards. This dope and ballistic calculator solution have been consistent under a variety of conditions. I’ve noticed other shooters and myself missing high quite a bit.
Conditions- 80-90F, ~70% RH, ~29.70 absolute. Wind gusty Left to Right 5-6, gust to 10. Mirage was present but very light. Like I said, I saw this enough from multiple shooters. I’m trying to figure out what we are missing?

 

[Hollywood 6mm]

The last two matches- I’ve noticed a trend of hitting high. Myself- I’ve got a rifle and ammo combo with dope verified out to 1000 yards. This dope and ballistic calculator solution have been consistent under a variety of conditions. I’ve noticed other shooters and myself missing high quite a bit.
Conditions- 80-90F, ~70% RH, ~29.70 absolute. Wind gusty Left to Right 5-6, gust to 10. Mirage was present but very light. Like I said, I saw this enough from multiple shooters. I’m trying to figure out what we are missing?

Mirage and/or light angle/condition. There's a target at Altus that will absolutely lie to you, especially when the sun is lower on the horizon in the winter time. Out to 700, your data will be dead on. You might be dead on at 8. The 840 target, though, you will be .2-.3 high, no matter the caliber. Go to any other lane, and the problem disappears. It's something about that target, where it sits in the shadows, and how the sun is sitting in the sky in relation to the trees and target that causes you to hit high. That's a different situation than what OP seems to be describing, though.

 

[hereinaz]

If the reticle is off after the shot, and you are using a gamechanger, first thing to try is a more solid rear bag. You can use a bag like a Gamechanger, but it is more difficult.

You have to take out all the slack in the whole bag so it is stiff and will remain stiff in the shot. Or, when you shoot beads and the bag will shift and the bottom will fall out from under you. You can't have anywhere for the extra beads to go.

I make bags, and have played with these things. Also, it is a problem with hunters shooting a heavy recoiling magnum that sits down and throws shots high if the bag is not solid enough.

Many ELR shooters use hard bags and adjust the elevation in the bipod for a reason.

 

[ForgivenAll]

Update...
I shot a NRL Border Wars match on Saturday (and got 2nd! That put the Yee in my Haw!), but afterwards, I got to spend some time shooting at the 1170 yd target repetitively to see what was happening.

Hopefully I am understanding and remembering it properly but I think I saw/heard Frank promoting arching up with the rifle stock (bipod on ground, barrel pointing down, stock elevated) buttpad seated to the center of the body from the shoulder pocket, then get into the prone position keeping engaged with the rifle. So, go from a tented position to the normal high-prone position (calling it this to differentiate from trying to shoot "prone" getting as close to the ground as possible).

When I did this and kept the bag tight under my stock, recoil pushed straight back more consistently.

Am I on to something?