Sighting in - confused

[yajsab]

Looking for a good explanation.

I was sighting in my rifle over the weekend. This is where I'm confused. It was shooting 3" high at 100 yard with 2 shots. This is my first time using the Leupold VX3HD, and I couldn't turn it lower due to the zero lock (my lack of info). So I decided to shoot at 200 yard. It was shooting 1" low with 4 shots. I am confused. According to the calculator, 200 yard zero should be 1.8" high at 100. With 3" high at 100, It should hit zero at 250 yard. Anyone has a good explanation?

Rifle: Savage 110 ultralite 6.5CM
Scope: Leupold VX3HD
Sight height: 1.50"
Bullet: Barnes VOR-TX LR 127grn

[jrebel]

Without knowing the velocity it would be very hard to say if that is normal or not.  I would think 4" drop from 100 to 200 yards is quite a bit......but, if you are shooting a shorter barrel 6.5 creed and pushing your pill at much slower velocities.....wouldn't be outside the realm of possibility. 

Lots can be causing it as well....
-  Shooters ability
-  Rest
-  Parallax adjusted??
-  Enough shots to verify what you are seeing?
-  What groups are normal for this round and rifle?  Is the variation normal for your grouping variables? 

ETC.   

[yajsab]

Without knowing the velocity it would be very hard to say if that is normal or not.  I would think 4" drop from 100 to 200 yards is quite a bit......but, if you are shooting a shorter barrel 6.5 creed and pushing your pill at much slower velocities.....wouldn't be outside the realm of possibility. 

Lots can be causing it as well....
-  Shooters ability
-  Rest
-  Parallax adjusted??
-  Enough shots to verify what you are seeing?
-  What groups are normal for this round and rifle?  Is the variation normal for your grouping variables? 

ETC.   

I don't have a chrono, so the box said 2825 fps at the muzzle.  A youtuber tested this bullet with a 22" barrel savage 110 and got average of 2786 fps.  Another youtuber tested it with a 18" barrel and average about 2680 fps.  So I used an extrapolation on this data and got around 2783 fps at 22" barrel.  Close enough with the test of the savage 110 with 22" barrel.

My groups at 100 yards and 200 yards are 1" or less.

[okie john]

Tight groups are a good sign. It could be a lot of things but I’m betting on the scope and/or mounts for most of it. If you just mounted it, then it could need a few rounds to settle in—that’s long been an issue with Leupold scopes.

The fact that it put 2 rounds in the right spot at 100 doesn’t mean much. How many rounds do you have through the rifle total? Did you torque the screws per manufacturers recommendation? Are you using some kind of thread locker to keep everything in place?


Okie John

[yajsab]

Tight groups are a good sign. It could be a lot of things but I’m betting on the scope and/or mounts for most of it. If you just mounted it, then it could need a few rounds to settle in—that’s long been an issue with Leupold scopes.

The fact that it put 2 rounds in the right spot at 100 doesn’t mean much. How many rounds do you have through the rifle total? Did you torque the screws per manufacturers recommendation? Are you using some kind of thread locker to keep everything in place?


Okie John

Torque per spec and used thread locker.

I haven't put too many round through it yet.  Maybe that might be the case.  However, my experience with setting up other rifles is different.  Only this one is way off.

[dreadi]

Let's say you did everything right and consistency is not an issue. So your reality doesn't exactly match the calculator/estimate. That's ok. Dial it in, shoot multiple distances, record your findings, and make your dope card. Then get chrono or borrow one or ask the guy on the line if he'll record your speed for you for a string of fire. That data is what you need to get closer to understanding and discernment.


Black Hammer Arms
www.blackhammerarms.com
The Guy On HuntWA Selling Suppressors
@blackhammerarms

[dreadi]

Tight groups are a good sign. It could be a lot of things but I’m betting on the scope and/or mounts for most of it. If you just mounted it, then it could need a few rounds to settle in—that’s long been an issue with Leupold scopes.

The fact that it put 2 rounds in the right spot at 100 doesn’t mean much. How many rounds do you have through the rifle total? Did you torque the screws per manufacturers recommendation? Are you using some kind of thread locker to keep everything in place?


Okie John

Torque per spec and used thread locker.

I haven't put too many round through it yet.  Maybe that might be the case.  However, my experience with setting up other rifles is different.  Only this one is way off.

If you torqued to spec and used thread locker, you did it wrong. Adding thread locker (mass) lowers the spec value.


Black Hammer Arms
www.blackhammerarms.com
The Guy On HuntWA Selling Suppressors
@blackhammerarms

[pickardjw]

Where are you located? I'd be happy to lend a Garmin chrono. Also wouldn't base much of anything off two or four shot groups. No idea if that low, high, left, right or center of your cone of fire or what the actual cone of fire is. See the graphic from Hornady attached.

Here's my process, all shot past the chrono:

1. One to three shots, measure adjustment from POI to POA with reticle. Make adjustment.
2. Five-Ten shot group. Use Ballistic-X, Hornady app, or similar to calc finer adjustment.
3. Make that adjustment and shoot three to twenty more to confirm. Set zero stop.
4. Update ballistics calculator with measured MV, true BC at furthest distance possible.

I was shooting off a bench last weekend, not ideal for me positionally (prefer prone) but attached is how steps 1-3 progress. Group sizes in each step depend on the known cone of fire of the rifle. New rifle gets larger groups, known rifle fewer.

I'm not worried about 0.1 MIL windage. Not going to call wind nearly well enough for that to make a difference.

[pickardjw]

Tight groups are a good sign. It could be a lot of things but I’m betting on the scope and/or mounts for most of it. If you just mounted it, then it could need a few rounds to settle in—that’s long been an issue with Leupold scopes.

The fact that it put 2 rounds in the right spot at 100 doesn’t mean much. How many rounds do you have through the rifle total? Did you torque the screws per manufacturers recommendation? Are you using some kind of thread locker to keep everything in place?


Okie John

Torque per spec and used thread locker.

I haven't put too many round through it yet.  Maybe that might be the case.  However, my experience with setting up other rifles is different.  Only this one is way off.

If you torqued to spec and used thread locker, you did it wrong. Adding thread locker (mass) lowers the spec value.


Black Hammer Arms
www.blackhammerarms.com
The Guy On HuntWA Selling Suppressors
@blackhammerarms

I've seen arguments that it does and doesn't. Nothing that sways me either way.

The real question is...what "spec" is being followed for each? Action screws, ring base, ring to scope. For my Tikka with factory bottom plastic and UM Rings, I'm at:

Action Screws: 55 in-lbs
Ring Base: 55 in-lbs (per UM)
Ring to Scope: 30 in-lbs (per UM)

[Stein]

A 2 shot group isn't really a group which is very possibly where much of your unexpected results are coming from.

If you buy a box of ammo, shoot 10 at 100 and 10 at 200 you will know where you are at for group size and drop.

[yajsab]

Thank you to all the comments/suggestions. I will shoot it again and see.

[Clearcut]

I’m assuming when you say you could get it to zero because of the zero lock and your lack knowledge means you figured out that the cap
Comes off and you can continue down to get it to zero? I’d find it hard to believe there’s not enough downward travel on the scope itself to get you to be able to 0 @100… as far as your group so being 4” different at those distances.. how many rounds down the barrel? Groups/ lots of ammo vary if you don’t have same lot. I’ve seen as much as 200fps from one box to another..

How far do you consider your effective range that you’re looking to shoot out too?? For target or hunting?? A last what calculator our you using to get your ballastics?

[The Gobble-stopper]

I may have missed soething, as I am reading this at 5 in the morning and getting back from surgery. But I don't believe I read anything about shooting a cold barrel. 2 shots with a cold barrel, tells you nothing when followed up by consecutive shots as barrel warms up. I was told to always shoot at least 5 to 10 shots to warm barrel and pay a layer of spent powder in the barrel for bullet to ride on. At that point to to a target to sight in. Has always worked for me. And with that said, along with most of the other actions layer out by the posts said within. My guns have been spot on without need of resighting for the best of 50 years. Also was told by my elders that it you are going to hunt with your rifle to always sight it in at the same outside temp that you expect to be hunting in. Don't sight in on a 75 degree day and then go hunting on a 28 degree day. You may be disappointed when making longer shots. Just my learned opinion. Good luck!

[yajsab]

I figured out the scope when I got home.  :-)

I bore sight and shot a few shots at 30 yard before shooting 100 and 200.  Also, I was in the forest at 3300'.  Not sure if this contribute much to the equation.

What I'm confused is that why 3" high at 100 yard yield 1" low at 200 yard.  The math doesn't work out.  I'm using shooterscalculator.com for the calculation. I also used jbmballistics.com for comparison.

This will be my high country deer rifle.  I would like to shoot up to 300 or 400 yards.

[deerlick]

you need good ballistic data to have any use of a ballistic app. should be good to a 1000 after a couple more shots.....

[yajsab]

you need good ballistic data to have any use of a ballistic app. should be good to a 1000 after a couple more shots.....

For discussion purpose based on the 3" high at 100 and 1" low at 200 impact, the only unknown variable is the speed.  With this data (assuming zero @ 200 yard), the calculator indicate a speed of ~2300 fps.  That's about 500 fps slower than what the box said (I understand it is 40 to 50 fps slower at 22" barrel).  Using the MOA rule, moving up 1" @ 200 will be 0.5" @ 100.  So with 3.5" high @ 100 and zero @ 200, the calculated speed is ~2200 fps.  Now it's roughly  600 fps slower than what the box said.

This is why I'm scratching my head on.

[pickardjw]

Can you post a picture of your targets? Bullet and BC used?

Ultimately, you're going to keep chasing your tail until you shoot a statistically significant amount of shots in each group.

Take the attached for another example of why you need to shoot more rounds in each group. If I ONLY used shots 1 & 2 (6 & 7) I'd say, "wow, I need to adjust my zero U1.25 MOA". In reality, those shots are towards the perimeter of the cone of fire and I only need to adjust U0.25 MOA. I'd be chasing that zero continuously and wondering why my ballistic solutions at further distances "aren't correct".

We don't know if your shots are in the center of the cone of fire or on the perimeter. Would also help to stop using linear units to describe angular measurements.

The limited data you have suggests a drop of 3.5 MOA between 100 and 200 yards. If your 100 yard shots are on the upper perimeter of the cone of fire and your 200 yard shots on the lower perimeter, the actual drop could only be 2.00 MOA, 1.75 MOA, 2.25 MOA, etc., which could be a correct ballistic solution.

[Clearcut]

I would if it was me with your situation verify your zero at 100… you said your shot groups at 100 and 200 were right and consistent so I would say that takes out scope movement.. I’d focus less on what your box said speed is. I have a chrono and while it’s gives me a very good starting point I still tend to reverse chrono or even tweak BC in a calculator to make my scope match what I see in paper…

[yajsab]

Here is a picture of the shots.

Don't pay attention to #7 but the elevation is consistent.  It was my bad.

[pickardjw]

Yeah, shoot two 5-10 shot groups. That target doesn't tell you anything useful.

[jstone]

Ammo? Maybe try different brands? I’m not an expert but my rifles love a certain brand