Range Report 105 Hybrids impacting high?

[Patty]

Looking for a little insight...

I shot big dog steel this weekend our at thunder valley precision. I arrived on Friday to check in and decided to check dope and participate in the king of the mile side match, since the facility was so cool and I’d never shot at a mile.

I’m shooting a 6 dasher at 2935fps. Using the AB custom curve in my kestrel.

I sit down and take a shot at 1000 yards, I am a half mil high. I’ve never seemed to have elevation issues before. I write it off as maybe a strange up draft, as my drop for my kestrel at 700 yards is spot on. Though shooters next to me are not experiencing the same issues.

Head over to the mile shoot, take my first shot, 2 mils high. Wow. What is going on?

I dive into my kestrel and verify all of my parameters and double check my speed over the magneto.
Out of curriousity, I change from the custom curve to a g7 BC, and turn it up until my mile dope lines up with what I observed. Which gives a g7 of .304

I head back to the 1000 yard target and try the dope that the .304 g7 gives, and it’s spot on, good center hit.


Anybody have an idea of what might be going on?

 

[Olen_4504]

tagging in to see folks thoughts - I was shooting right along the OP and no dope issues - so we are pretty certain it wasn't anything environmental

one other shooter also shooting 105s experienced something extremely similar to OP at the same time

 

[Patty]

tagging in to see folks thoughts - I was shooting right along the OP and no dope issues - so we are pretty certain it wasn't anything environmental

one other shooter also shooting 105s experienced something extremely similar to OP at the same time

Except his BC correction was much more mild, he used a g7 of .285 to line up

 

[Mordamer]

Did you change anything else on your setup before shooting?

Did you verify velocity after impacting high?

I would question scope tracking and velocity in this situation. BC of the bullet is not going to change that much. That is a huge change in BC. I have shot a lot of Hybrids and a G7 of .275 has always been correct or very very close to correct.

 

[Milo 2.5]

Looking for a little insight...

I shot big dog steel this weekend our at thunder valley precision. I arrived on Friday to check in and decided to check dope and participate in the king of the mile side match, since the facility was so cool and I’d never shot at a mile.

I’m shooting a 6 dasher at 2935fps. Using the AB custom curve in my kestrel.

I sit down and take a shot at 1000 yards, I am a half mil high. I’ve never seemed to have elevation issues before. I write it off as maybe a strange up draft, as my drop for my kestrel at 700 yards is spot on. Though shooters next to me are not experiencing the same issues.

Head over to the mile shoot, take my first shot, 2 mils high. Wow. What is going on?

I dive into my kestrel and verify all of my parameters and double check my speed over the magneto.
Out of curriousity, I change from the custom curve to a g7 BC, and turn it up until my mile dope lines up with what I observed. Which gives a g7 of .304

I head back to the 1000 yard target and try the dope that the .304 g7 gives, and it’s spot on, good center hit.


Anybody have an idea of what might be going on?

Did you chrono your rifle? I find it hard to believe a .304 BC was achieved. In the bullet library, the Kestrel has it at .273 BC, and .273-275 matches up with 3 BR variant cases I shoot, and I am at a way higher elevation than thunder valley.

 

[Patty]

Stated in OP, yes, verified velocity after impacting high.

 

[Patty]

Did you change anything else on your setup before shooting?

I would question scope tracking and velocity in this situation.

No changes.

Velocity was verified the day before and after impacting high.

Scope is a Tangent theta and has tracked perfectly for me for the last 8 months.

 

[Mordamer]

No changes.

Velocity was verified the day before and after impacting high.

Scope is a Tangent theta and has tracked perfectly for me for the last 8 months.

What were the atmospherics on the day of shooting?

What was the dope that you needed to make impacts?

 

[Patty]

What were the atmospherics on the day of shooting?

What was the dope that you needed to make impacts?

DA 1768
70 degrees F

Kestrel called for 7.8mil to hit at 994yd

Actual center impact 7.3mil

Kestrel called for 23.7mil at 1729yd

Actual 21.7mil

 

[kthomas]

what was your bipod setup? Do you have one of those flimsy universal RRS rails mounted underneath your rifle?

Where you loading into your bipod differently than how you zero?

 

[Lowlight]

It's funny over the years, a ton of people reported their dope being significantly off at Thunder Valley

I don't know if they get bad thermals or if their ranges are off, but we have seen it a bunch that their dope and distances don't match.

 

[Patty]

what was your bipod setup? Do you have one of those flimsy universal RRS rails mounted underneath your rifle?

Where you loading into your bipod differently than how you zero?

Bipod is a TBAC mounted directly to the fore end of a MDT ACC Chassis arca.

No, and this was shot off a bench in the same exact manner that I zeroed the rifle.
Zero is good, 10 shots under a dime.

 

[Patty]

It's funny over the years, a ton of people reported their dope being significantly off at Thunder Valley

I don't know if they get bad thermals or if their ranges are off, but we have seen it a bunch that their dope and distances don't match.

I have heard some of this, but am wondering why several other shooters shooting right along side me didn’t experience this. We had a couple guys out there with a PLRF verifying the ranges. I even ranged the 1k and mile target myself at 994 and 1729.

I am really much less concerned about being off at the mile because I understand how many variables can effect this, but being off at 994, is something I have never experienced. My elevation has always been solid.

 

[Lowlight]

those hills could create a thermal, but over the years we heard about this happening a bunch.

It's a common questions with a lot of guys after shooting there. Never been there so can't say, but I have seen this question come up before and it's specific to Thunder Valley.

I also wonder if the place creates an angle shot, not sure how, but it would explain some of it. How it happens to some and not others I don't know, but it's a questions I have seen before.

Snell's Law maybe,

is the sun in front of you, maybe there is an issue with the light and the targets giving it the appearance of being where it is not. The humidity and thermals could carry the image UP so you are aiming higher than where the target actually is. I have seen in AK with their high humidity and dense air, the bullet will go from POA to POI to hitting .5 mils high for about an hour and then back to normal again when the sun moves. of you have X amount of cloud cover, partly cloudy days, you see when the sun is out and not when it goes behind a cloud.

From the pictures I have seen of the place, really my only point of reference along with reports like this, I would guess the rolling hills are the issue. Does mean they create updrafts, snells law combined with thermals, hard to say, Tom Sarver might know why it happens

 

[pbatesaz]

Tag

 

[Sheldon N]

I would chalk it up to some sort of environmental issues before I would believe that a 105 Hybrid had a G7 of .304. Even pointed Hybrids barely break .280G7 for me.

 

[kthomas]

I would chalk it up to some sort of environmental issues before I would believe that a 105 Hybrid had a G7 of .304. Even pointed Hybrids barely break .280G7 for me.

Yeah .304 definitely doesn't make sense.

 

[Patty]

Yeah .304 definitely doesn't make sense.

Scratching my head too, because while I’ve seen some folks mention upping it to .284 before, .304 is insane.

I have checked every box I can think of as to why this was happening. I shot the whole match with a BC of .304 input and managed to come in 13th. It was too difficult to tell on the long stages where misses were because it was all tall grass.

 

[Patty]

I would chalk it up to some sort of environmental issues before I would believe that a 105 Hybrid had a G7 of .304. Even pointed Hybrids barely break .280G7 for me.

I really want to, just having a hard time understanding why it was just me out of the 20 or so shooters up there at the time, if it was environmental.

 

[Lowlight]

did everyone shoot from the same place ? or was there as a firing line with guys lined up

 

[Milo 2.5]

I really want to, just having a hard time understanding why it was just me out of the 20 or so shooters up there at the time, if it was environmental.

Is your kestrel updated to version 1.27? Starting around June to mid July mine threw some wacko numbers. I finally updated it and things are back to normal, one key thing I noticed was the 110 sierra 6mm bullet was way shorter than it was supposed to be, and it had to change on it's own just by updating profiles.
Also, were you the only one shooting light bullets? Or were there more doing so?

 

[Patty]

did everyone shoot from the same place ? or was there as a firing line with guys lined up

They have a bunch of concrete benches and there were shooters at most of them, my buddy was right next to me, maybe 4 feet to my left vand another to my right.
Weather was nice, not humid, it was cool, no real mirage to combat. Probably the clearest conditions I’ve shot in all season. It was about 2-3pm sun was not in our faces at all nor was it directly behind us.

 

[Patty]

Is your kestrel updated to version 1.27? Starting around June to mid July mine threw some wacko numbers. I finally updated it and things are back to normal, one key thing I noticed was the 110 sierra 6mm bullet was way shorter than it was supposed to be, and it had to change on it's own just by updating profiles.
Also, were you the only one shooting light bullets? Or were there more doing so?

Yes I am updated to 1.27, I’ll double check the length in the app though.
The amount of people up there shooting 105 hybrids we’re probably the majority.

Where are you seeing a bullet length parameter in the kestrel? @Milo 2.5

 

[Sheldon N]

You able to run your numbers through some other solver like JBM to see if the math holds up?

 

[Patty]

You able to run your numbers through some other solver like JBM to see if the math holds up?

Good idea. I’ll give it a go a report back.

 

[Lowlight]

You were sitting at a bench ?

Where you bladed to the side, in other words was a it a typical bench with the sides cut or was it was square and where both your elbows on the bench?

I think I know the cause, especially if you shot off the bench

 

[Patty]

Hornady 4DOF calls for 7.66

JBM calls for 7.5

 

[Patty]

You were sitting at a bench ?

Where you bladed to the side, in other words was a it a typical bench with the sides cut or was it was square and where both your elbows on the bench?

I think I know the cause, especially if you shot off the bench

It’s a typical bench with the sides cut but I always bring my bipod in far enough to get both my elbows up on the bench. This is the same as I zero my rifle at my home range.
I also shot prone off the concrete floor next to the bench for the mile shoot.

10 shot zero group from the day before is attached.

 

[Lowlight]

Ya,

That is fine, but doesn't show the POA, off a bench depending on your recoil management you can hit high by .3 or so vs other positions.

You rock back under recoil if you are bladed and it causes the group to rise as well as it will bleed of MV

You'll shoot the same, but not in the same place

 

[Patty]

Ya,

That is fine, but doesn't show the POA, off a bench depending on your recoil management you can hit high by .3 or so vs other positions.

You rock back under recoil if you are bladed and it causes the group to rise as well as it will bleed of MV

You'll shoot the same, but not in the same place

I totally get it, but, if that’s what was going on here, wouldn’t that have been present at all the other distances I shot inside 1000 from the same bench?

 

[Lowlight]

Not necessarily

 

[swage2712]

It's definitely and angled shot at Thunder Valley. Anything over 600 yards and you're shooting up hill substantially.

 

[Patty]

It's definitely and angled shot at Thunder Valley. Anything over 600 yards and you're shooting up hill substantially.

Are we talking about the same area of the place? It’s definitely pretty straight out, not uphill by any means that would change your dope. My buddy took this picture from the bench. Besides, everyone would be experiencing these issues if that were the case.

 

[Olen_4504]

According to my calculations with my bullet: you’d need a 15 degree incline to change the drop by .3 Mils. Do we think that 1000yd berm is at a 15 degree angle to the shooting area?

Also if that was the case - myself and the other guys would have had the same issue - and we didn’t.

 

[Patty]

According to my calculations with my bullet: you’d need a 15 degree incline to change the drop by .3 Mils. Do we think that 1000yd berm is at a 15 degree angle to the shooting area?

Absolutely not

 

[Sheldon N]

I think the question gets answered the next time you go shoot the same load at distance at some other location. If if's your gun and not the local conditions then the dope will hold true. If it goes back to something like a .280G7 then you know it was a local effect.

Now if you go elsewhere and still have to use a .304G7 I'd start looking at all inputs. Suspicion would be some sort of stacked tolerances effect. Chrono reading slightly slow + zero being slightly high + turret tracking maybe not 100% perfect + ballistic solver being more aggressive than other solvers. Maybe not one massive error but lots of little errors combined.

Had a recent match where I sent all the rounds over the tops of targets first stage. Turned out that it was a combination of my velocity input being a touch too slow and my zero being 0.1 high.

 

[Patty]

I think the question gets answered the next time you go shoot the same load at distance at some other location. If if's your gun and not the local conditions then the dope will hold true. If it goes back to something like a .280G7 then you know it was a local effect.

Now if you go elsewhere and still have to use a .304G7 I'd start looking at all inputs. Suspicion would be some sort of stacked tolerances effect. Chrono reading slightly slow + zero being slightly high + turret tracking maybe not 100% perfect + ballistic solver being more aggressive than other solvers. Maybe not one massive error but lots of little errors combined.

Had a recent match where I sent all the rounds over the tops of targets first stage. Turned out that it was a combination of my velocity input being a touch too slow and my zero being 0.1 high.

Absolutely, and that’s the plan, I’ll be getting out this Saturday to hopefully put this one to bed. Thanks for the input guys, I’ll follow up after I get out and shoot it again.

 

[KYpatriot]

What were the winds? That place has some serious potential for vertical wind. Did you record a wind direction/call for each shot? How many rounds did you fire to confirm you were consistantly high?

Since the bullet didnt get slicker, its environmentals, you, the ammo, the rifle, or the scope. Verifying velocity likely rules out ammo. As mentioned above it could be stacking of many small things.

Check to make sure something you dont normally look at in the kestrel setup, like sight height or zero offset was accidentally changed somehow.

Thanks to LL now I have to go look up snell’s law lol.

 

[Patty]

What were the winds? That place has some serious potential for vertical wind. Did you record a wind direction/call for each shot? How many rounds did you fire to confirm you were consistantly high?

Since the bullet didnt get slicker, its environmentals, you, the ammo, the rifle, or the scope. Verifying velocity likely rules out ammo. As mentioned above it could be stacking of many small things.

Check to make sure something you dont normally look at in the kestrel setup, like sight height or zero offset was accidentally changed somehow.

Thanks to LL now I have to go look up snell’s law lol.

A pretty steady 6-7mph full value. 1.5mil had me centered up at 994 yd.

Again, i would think if it was environmental related, then the shooters shooting right next to me would have experienced the same thing.

I dove into my kestrel and made sure all of my parameters were correct. Im looking forward to confirming my zero, and shooting at a distance, hoping it didnt somehow get bumped on the ride up to the match.

 

[Patty]

I am not super familiar yet with Hornady's take on axial form factor, but what if? if i give an axial form factor of .94 for my gun, all my dope lines up, even to a mile.

https://hornadykestrel.com/mwdownloads/download/link/id/347/

 

[morganlamprecht]

did you happen to chrono the day of (when you were high)?

 

[Patty]

did you happen to chrono the day of (when you were high)?

Sure did, immediately. Barrel had 340 rounds on it and I thought maybe I got a late speed up or something.

Nope, velocity was the same as it’s always been.

 

[morganlamprecht]

Sure did, immediately. Barrel had 340 rounds on it and I thought maybe I got a late speed up or something.

Nope, velocity was the same as it’s always been.

welp, that throws that out lol ive been tracking bore condition vs velocity in a few barrels that could have made that error up, but the chrono would have shown it

 

[lukejr985]

Ya,

That is fine, but doesn't show the POA, off a bench depending on your recoil management you can hit high by .3 or so vs other positions.

You rock back under recoil if you are bladed and it causes the group to rise as well as it will bleed of MV

You'll shoot the same, but not in the same place

Frank looking for clarification of the above statement, does this error show up more on a bench vs other positions? Im curious if the alternate positions we see in PRS type shooting could cause this error as well, or does it only impact shots at a further distance?

 

[Lowlight]

You can see it in any alternate position, it's a recoil management thing.

Most PRS guys have decent recoil management and will not see it, maybe on a free recoil shot you might see it, but most are holding the rifle DOWN so it's not moving back and up.

But you can make this appear any number of ways, it's one of the reasons why two shooters might have a different zero, recoil management tells the bullet where the barrel is when the bullet releases, any change in management changes the location of the barrel

 

[lukejr985]

You can see it in any alternate position, it's a recoil management thing.

Most PRS guys have decent recoil management and will not see it, maybe on a free recoil shot you might see it, but most are holding the rifle DOWN so it's not moving back and up.

But you can make this appear any number of ways, it's one of the reasons why two shooters might have a different zero, recoil management tells the bullet where the barrel is when the bullet releases, any change in management changes the location of the barrel

Cool thanks, ill put that one in the tool box

 

[_Raining]

Snell's Law maybe,

is the sun in front of you, maybe there is an issue with the light and the targets giving it the appearance of being where it is not. The humidity and thermals could carry the image UP so you are aiming higher than where the target actually is. I have seen in AK with their high humidity and dense air, the bullet will go from POA to POI to hitting .5 mils high for about an hour and then back to normal again when the sun moves. of you have X amount of cloud cover, partly cloudy days, you see when the sun is out and not when it goes behind a cloud.

From the pictures I have seen of the place, really my only point of reference along with reports like this, I would guess the rolling hills are the issue. Does mean they create updrafts, snells law combined with thermals, hard to say, Tom Sarver might know why it happens

I wonder how many misses are brought about from light. I had never even considered light as a problem until I saw this video:


I would love to see more content like this from different places. Is there any rules of thumb for this sort of thing, as far as trying to correct for it based on sun angle, temperature, humidity, cloud cover etc (IDK what factors play a part in this sort of thing).

 

[Patty]

Got out to shoot today and hung a nice big plate at 976 yards. Checked zero, checked speed, all the same as before.

Custom curve, called for 7.4 mils. Put me .2 high on the plate

.304 G7 I used for the match 7.0 mils, put me .2 low on plate.

.286 g7 put me dead on waterline. With 7.2 mils.

 

[ShtrRdy]

Thanks for the update and sharing your findings with us!

 

[Patty]

It’s also worth noting that I tested a new lot of 105 hybrids that were not as long, and they were 25fps faster, but also lined up at .286 g7