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Shot my first 300 yard match today, 40 rd slow fire, previously shot only to 200 yards. Did well score wise but after comparing what I dialed in, things really got wonky.

Using Leupold vx6 3-18 with varmint reticle in low warne mount about 1.5" above bore. Rifle is Weatherby Mk-V in 270win. with 26" barrel threaded w/ WC suppressor. Ammo factory Hornady 130SST superformance.

This setup is well zeroed at 200 (I thought). Doing my initial sighting shots I used the first hold below the crosshairs which is supposedly for 300 yards and about 5.6-7.1" of drop. However I was quite high and had to adjust my turret down a total of 6 clicks which on a 1/4moa scope at 300 yards is 4.5".

After adjusting crosshairs 6 clicks down and using the "300" yard hold mark, I was anywhere from 8 to x ring. I got home and figured the math and got confused. The scope hold mark is for 5.6" drop for 300 yard target when zeroed at 200, but I had to dial off 4.5" of that elevation which would put my actual drop at 300 yards at 1.19" with 200 yard zero??

Hornady puts the 300 yard drop for this load at 5.7" and handloads.com ballistic calculator puts it at 5.77" drop. Leupold tailored the hold mark at 5.69", so everybody seems to have the same idea, except what the bullet actually showed.

I haven't chrono'd the ammo, Hornady has typically been spot on factory loads in my past measures, and even bumping up th velocity substantially it yields minimal difference to bridge the gap. I zeroed in about 50 degree weather and it as mid 80s today, again shouldn't be enough to change it, and same altitude.

Here's the other factors I can think of: 1) originally used lead sled to zero at 200 on bench and shot today prone off bags at 300, 2) the angle to target impacted the poi combined with other factors... I would estimate the angle was around 20 degrees maybe.

Curious what more seasoned shooter's thoughts are? I guess I have to ultimately go back out and shoot 200 under same conditions to really know for sure as I may be doing apples to oranges with the varying shoot factors. I never imagined it could be this pronounced. Glad I am learning more now and not in the field. As it's said, "...the bullet doesn't lie...".
 

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Other than getting a newly mounted optic zeroed, you should always obtain your working zero in the same manner you will be using it. I have different zeros for my match guns based on shooting position or shooting from the bench. With that being said, it sounds like you potentially zeroed on the wrong hash mark initially, or had your parallax out of whack, or a combination of the two. A delta of ~1" sounds about right if you sighted in using a sled, then shot while on the rifle and had zeroed on the second hash mark.

-Alexander
 

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Shot my first 300 yard match today, 40 rd slow fire, previously shot only to 200 yards. Did well score wise but after comparing what I dialed in, things really got wonky.

Using Leupold vx6 3-18 with varmint reticle in low warne mount about 1.5" above bore. Rifle is Weatherby Mk-V in 270win. with 26" barrel threaded w/ WC suppressor. Ammo factory Hornady 130SST superformance.

This setup is well zeroed at 200 (I thought). Doing my initial sighting shots I used the first hold below the crosshairs which is supposedly for 300 yards and about 5.6-7.1" of drop. However I was quite high and had to adjust my turret down a total of 6 clicks which on a 1/4moa scope at 300 yards is 4.5".

After adjusting crosshairs 6 clicks down and using the "300" yard hold mark, I was anywhere from 8 to x ring. I got home and figured the math and got confused. The scope hold mark is for 5.6" drop for 300 yard target when zeroed at 200, but I had to dial off 4.5" of that elevation which would put my actual drop at 300 yards at 1.19" with 200 yard zero??

Hornady puts the 300 yard drop for this load at 5.7" and handloads.com ballistic calculator puts it at 5.77" drop. Leupold tailored the hold mark at 5.69", so everybody seems to have the same idea, except what the bullet actually showed.

I haven't chrono'd the ammo, Hornady has typically been spot on factory loads in my past measures, and even bumping up th velocity substantially it yields minimal difference to bridge the gap. I zeroed in about 50 degree weather and it as mid 80s today, again shouldn't be enough to change it, and same altitude.

Here's the other factors I can think of: 1) originally used lead sled to zero at 200 on bench and shot today prone off bags at 300, 2) the angle to target impacted the poi combined with other factors... I would estimate the angle was around 20 degrees maybe.

Curious what more seasoned shooter's thoughts are? I guess I have to ultimately go back out and shoot 200 under same conditions to really know for sure as I may be doing apples to oranges with the varying shoot factors. I never imagined it could be this pronounced. Glad I am learning more now and not in the field. As it's said, "...the bullet doesn't lie...".
I cant help find your way here. Just want to make sure you are aware Leopold will provide elevation turrets for a given bullet caliber and weight.
As I understand these are free with scope purchase. Just tell them what you want.
 

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Assume you had scope set to max zoom 18X to use the hold over marks. Marks are veery approximate. Leupold, Burris, etc have calibration software online to input ballistic data of your load (BC, velocity, etc). Marks are different at every zoom level and program will give you that data.
 

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None of the dial in is plug and play. The ammunition rarely is the same calculated settings for your dots. Atmospherics can do that much at 300 on a given day. It's a SWAG on the charts that are given by a factory. We get sighters for a reason. My 95 SMK showed 12 MOA come up at 500 according to my recorded velocites and the programs for that bullet and BC. Actual come ups were 10.5 from 100 yards. 7.5 inches less. I was happy..LOL I know the speed was right as we have it the same on various rifles at various places with the same load + or - 5 FPS. Obviously the BC is not real world as Mr. Litz proves over and over again.

Greg
 

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Discussion Starter · #6 ·
Thank you for the thoughtful and very helpful real world experience you all can share I really appreciate it!
 
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