Unexplained elevation shift, reason?

[patriotnation]

This may be long but bear with me please. Yesterday I shot a finale and on my last stage of the day my misses were all high 2 mils. This was a barricade timed stage 400 yards and 500 yards on 8” plates. Grass behind so not much for feedback as I was missing I adjusted for wind only a couple tenths and nothing for elevation. Scored zero and after spotter said I was high.
Stage before was a roof and I did well for me 8 out of 10, it was a no dial stage so I had pushed down my elevation turret before shooting that stage which I normally leave it up unlocked. After stage I lifted it then dialed zero.
Confused why I was suddenly high, after our squad finished, I laid prone and shot ten rounds out to see where on those targets or how much I was off.
At the 500 yard target I had to hold center as wind was from behind, and it was 2 mils high. That is a lot
My dope was correct, no problem there.

Got home checked torque on all screws, set screws, action, rings, rail bolts and also muzzle brake tight, no problems. Barrel looks clean and clear.

It is a Terminus Zeus QC, 6 Dasher 105 hybrid in once fired Alpha OCD , Proof prefit in an MDT ACC with gen 2 Razor HD

I’m not sure if the elevation cap had something to do with this, it is unexplainable to me.

I suppose next is take it to my range and confirm zero at 100, maybe do a test at distance with a level line adjusting elevation for each shot, ladder test I suppose?

Before the match I zeroed and it was fine.
Rifle did not get bumped or fall over that I know of after the previous roof stage.
Stage before this all was fine.
Any suggestions I thank you for any help or advice.

 

[Aftermath]

Yeah, you are gonna have to figure out what you are doing different by launching some rounds. You zeroed before the match so I would think it's something minute you are doing, not the mechanicals.
My first inclination is butt of the rifle is low or is being allowed to go low during recoil.

 

[NHPiper]

That is bizarre. Maybe something with the internal scope erector got stuck. What is the scope?

Maybe try quickly snapping it with your wrist a few times up and down to unbind anything and then shoot a group at 100yds to confirm zero?

Were you shooting with a suppressor?

I ran into an issue with my AT-X that was similar for windage but the rear of my S&B had taken a pretty good hit when my backpack fell again my Jeep.

I sent the scope in for service and it had nothing wrong. My zero wanded 9 mils (yes that is correct as mine mils). Only thing I could figure was the action rail on the top of the action and shifted even with its recoil lug. I pulled it off and retorqued it. No issues since.

 

[tucaz]

could a new lot of the ammo be hotter?

or ammo left in the hot sun vs when you zero’ed?

just spit balling. i know nothing.

 

[spife7980]

You have the butt solid in your shoulder?
Yank the rifle up by the barrel and the quick change let it wiggle a smidge or bounced it off the roof when you were getting off the prior stage?

 

[AccuSol-ERN]

If you don't find the problem to be scope, shooter, or other mechanical problem. I would be interested in you trying to put a little torque on that quick change barrel and see if that helps. Nothing crazy..
..maybe 30-50lbs

I have always wondered at what point does a handtight barrel start to have inconsistency in point of impact given the amount of heat and pressure during courses of fire.

Ern

 

[-H-]

2 mils?!?

I’d do a tracking test to make sure your scope is consistently tracking mechanically.

 

[morganlamprecht]

Not sure how long you’ve ran the gen 2 razor, but a common issue when weird things like this happen with that scope is from not getting the 3 set screws on the turret tight enough after zeroing with the center stem.

Back when they first came out the general advice was snug them up until they squeak…which gives most people pause coming from other scope brands/types. supposedly it was something to do with the internals being tool steel where the screws touched instead of aluminum like most scopes so it took quite a bit of torque to make them bite…the included tool typically wasn’t strong enough to even do it (at least not set and forget, maybe if u constantly retightened them it would be fine)

People would describe the same issue as u tho…all checks good, then randomly off…rezero, looks good again…then after some dialing, off again. They’d get told “tighten the screws”. They’d say “I used the included tool”. “Toss the tool and crank it with a real Allen…”

Problems would go away

That’s the first thing I’d check

 

[papershredder]

Adding to what's been asked above, Parallax on the scope set correctly? How much wind from your 6:00 and how much slope does the range have? Any major changes to the weather (specifically baro pressure) and temperature happen from when you zeroed to when you shot the last stage? Ammo in sun all day? Hot barrel? Combinations of the above?

 

[patriotnation]

That is bizarre. Maybe something with the internal scope erector got stuck. What is the scope?

Maybe try quickly snapping it with your wrist a few times up and down to unbind anything and then shoot a group at 100yds to confirm zero?

Were you shooting with a suppressor?

That is what I thought, Vortex Razor HD gen 2

I will

No suppressor, a Hellfire muzzle brake and it is tight, not loose at all.

 

[patriotnation]

could a new lot of the ammo be hotter?

or ammo left in the hot sun vs when you zero’ed?

just spit balling. i know nothing.

nope, all same ammo 30.7 grains Varget 105 berger hybrid 10,000 off lands
Not in sun, took last mag from backpack and figured out I was 2 mils high at 500 yards after we were done for the day. Crazy I know.

 

[patriotnation]

You have the butt solid in your shoulder?
Yank the rifle up by the barrel and the quick change let it wiggle a smidge or bounced it off the roof when you were getting off the prior stage?

yes solid. and prone afterwards solid did the same
no change to the rifle other than the scope cap being depressed down and then up again to return to zero between the stages.

 

[patriotnation]

Not sure how long you’ve ran the gen 2 razor, but a common issue when weird things like this happen with that scope is from not getting the 3 set screws on the turret tight enough after zeroing with the center stem.

Back when they first came out the general advice was snug them up until they squeak…which gives most people pause coming from other scope brands/types. supposedly it was something to do with the internals being tool steel where the screws touched instead of aluminum like most scopes so it took quite a bit of torque to make them bite…the included tool typically wasn’t strong enough to even do it (at least not set and forget, maybe if u constantly retightened them it would be fine)

People would describe the same issue as u tho…all checks good, then randomly off…rezero, looks good again…then after some dialing, off again. They’d get told “tighten the screws”. They’d say “I used the included tool”. “Toss the tool and crank it with a real Allen…”

Problems would go away

That’s the first thing I’d check

I did not check those, thank you. I have found those to be loose before so that rings a bell. I will check
You may be correct and it sure sounds like it
Thank you!

 

[patriotnation]

Adding to what's been asked above, Parallax on the scope set correctly? How much wind from your 6:00 and how much slope does the range have? Any major changes to the weather (specifically baro pressure) and temperature happen from when you zeroed to when you shot the last stage? Ammo in sun all day? Hot barrel? Combinations of the above?

Parallax was good
variable wind from behind but that only affected left or right and it switched on us as we shot going 7:00 or 5:00, small enough plate to give a lot of us at that time trouble, but nobody zeroed that stage but me, and only a little slope downward 2 degrees at most.

temp would not account for that.
I think it is scope turret set screws loose as above.

I'll check

 

[patriotnation]

I checked the set screws on the turret of the Razor HD and yes, it had one screw backed way out so it probably was not engaging and surely the reason for my trouble. I will need to add that to my checklist from now on.

THANK YOU! that is a relief to know at least. I will still confirm once I re-zero and still do a ladder test when I have time.

 

[WB300]

Try to duplicate your exact position, all the way down to exact placement of rifle in shoulder, angle of hips/shoulders, placement of hands/feet, weight distribution...etc.

I learned (I think) the hard way that even though my wobble zone was within my target, having my hips directly under my shoulders while sitting (bad position), I sent 2 rounds high. Recoil mgmt sucked and I saw sky in the scope each time.

Went through the diagnostic process like you and that's the only thing I could find that gave me inconsistency. I'm still new to this, but figure a class on positional shooting is needed.

I apologize if this sounds newb-ish, but it may spark conversation and hopefully readers like me can learn.

 

[morganlamprecht]

I checked the set screws on the turret of the Razor HD and yes, it had one screw backed way out so it probably was not engaging and surely the reason for my trouble. I will need to add that to my checklist from now on.

THANK YOU! that is a relief to know at least. I will still confirm once I re-zero and still do a ladder test when I have time.

Good deal, hopefully that was it.

You being off 2mil was a good tip off, a shooter with any decent experience (which sounds like you have) isn’t goin to be off because of a position that far at 500, and there’s no environmental factors goin to account for that much shift either

.2, sure…2mil, no way lol something was either loose or just flat out broke

I ran a, couple gen 2s for 5+ yrs in comps (still have one) and crazy as it sounds, the turret stem screws are absolutely wrenched lol if it breaks/strips, vortex will fix it, but it’s never happened…and more importantly it’s never come loose and lost the zero.