NEED HELP WITH A VORTEX SCOPE

[AZ_SAWBUCK]

I'm a little frustrated and could use some knowledge from some of you. I have a semi custom rifle that I recently mounted a new scope on, its a Vortex Viper HS 4-16x50 w/ 1/2moa elevation turret. Got it sighted it in at 200 yards and it seems to be grouping ok. About 1.5" groups at 200.

 

I'm new to dialing turrets so I go to the vortex site and build a drop chart. I set it up in clicks (not MOA) so I could just count the clicks and be dialed in at ## yards. I don't reload yet so I'm shooting factory ammo. Hornady Superformance 180 gr SST. So I set up a paper target at 450 yards. Check my chart....... it says dial 10.1 clicks. I shoot in the prone position off a bipod and used a sand sock with my support hand. Shoot a 4 shot group and am surprised at the results. My group is 12" high and its a 4" group.

 

Does it seem that I messed up the chart some how? What do you guys come up with on adjustment given the load and information given? Is there a better chart or system I should use? I know I should be shooting hand loads but I have to work with what I have right now. Any help would be appreciated.

 

Rifle: Remington 700 .300 win mag, HS Stock bedded, Timney trigger, custom break, Talley one piece rings and bases. Harris Bipod

 

THX Jason

.300 HORNADY DROP CHART.pdf

[Couzer]

Are you taking the BC (ballistic coefficient) and velocity (did u chronograph the speed) into consideration?

[AZ_SAWBUCK]

When I built the chart on the vortex site I used the BC and velocity provided from Hornady. BC .48 and Muzzle Velocity of 3130 fps. I did not chronograph.

[AZ_SAWBUCK]

The drop chart is attached and has the inputs at the top.

[Chef]

It looks like you need to chrono your load to determine its velocity. Then you can enter that into the program and get a more accurate drop chart. Even then, you need to verify the clicks by shooting at those distances and adjusting accordingly.

 

The velocity listed for a particular load may not be true to your rifle, taking barrel length etc into consideration.

 

Factory ammo also doesn't have the best consistency either, so consider this when shooting for groups.

[Chef]

Oh yeah, nice looking rifle!

[muledeerarea33?]

Another post today said something about Hornady ammo being out of spec? Might scan the forum for that info before racking your brain, could be bad ammo?

[lancetkenyon]

A lot will change the drop chart.

Elevation, temperature, barometric pressure, scope mounting height, actual BC, actual velocity, barrel whip, inaccurate parallax setting, inaccurate 200 yd. Zero, etc.

[kwp]

Based on your info you should be around 5 moa so 10 clicks is right. Like some of the others have said something else is off. I think it must be a combination of things because if it was just a bad muzzle velocity it would have to be crazy fast to be that high at 450 yards. Was 450 yards verified with a rangefinder?

[10Turkeys]

From what I was able to see that is a pretty large objective lens on the end of that scope and plenty of daylight between the scope and barrel that would be the first thing I would look at. The following is just my two Abe's so run with it how you will. I spent 8 years in a Field Artillery unit which is just something that goes bang on a much larger scale, you can come up with any drop chart you would like that is your should hit data, take the gun to the range shoot it at the different ranges that you my think you might use, that is your did hit data. My best advise is always go with your did hit data!

[Str8Shot]

Based on your info you should be around 5 moa so 10 clicks is right. Like some of the others have said something else is off. I think it must be a combination of things because if it was just a bad muzzle velocity it would have to be crazy fast to be that high at 450 yards. Was 450 yards verified with a rangefinder?

and is it a true 450 yards no Angle to adjust for ? Sounds funny but I have seen guys put a target out at 500 yards a bit up on a hillside and shoot prone putting enough angle that they were constantly shooting high... Used another rangefinder that adjusts for angle and ranged from prone position and all the sudden they were hitting where they expected... But as others have said many other factors that I am sure you will work out by trial and error.

[STOMP442]

Did hit data is exactly right.calculators are great for getting close but nothing beats field data.

 

Looking at your set up I would guess your scope height to be at least 1.8 something. The actual BC of that bullet is going to be .470 or less as the actual litz tested BC of the 178 Amax has a BC of .469. These numbers will not change your drop chart much but the more accurate info going in will produce more accurate calcs coming out.

 

Did you zero your rifle in the same position and set up you are shooting now? Sometimes adding a bi-pod can change things drastically and the position of your head a cheek weld is different when shooting prone vs off a bench which can also cause issues. Paralx could also be a culprit is your scope focused for that range? Lots of things to consider good luck and I hope you figure it out.

[lancetkenyon]

To add to what I said earlier, make sure your data that you sighted in your rifle is correct.

You will need:

Elevation where you shot.

Barometric pressure when you shot.

Temperature when you shot.

Any inclination declination in degrees when you shot.

Actual scope mounting height above center of bore.

Ensure proper parallax was set.

Ensure proper techniques were adhered to.

Get corrected BC from Litz, not just published BC from manufacturer.

Verify velocity.

 

When you go back out to shoot, and variables WILL throw your dope off. Sometimes WAY off.

Higher temps mean less dense air, but also can cause faster velocities due to hotter loads.

Higher elevations mean thinner air, resulting in less drag and less drop.

Higher barometric pressure has similar effects to higher altitude.

Incline or decline in target will give you an actual longer distance from a chrono than a true level reading would, meaning less drop.

Scope mounting height discrepancies will not give a true algorithm to your ballistic program, and will cause dope errors.

Bad parallax adjustment means you crosshairs can float and move around on target, meaning change in point of aim.

Bad BC will not give a true algorithm to your ballistics program, and will cause dope errors.

Bad velocity inputs will not give a true algorithm to your ballistics program, and will cause dope errors.

Barrel whip inconsistencies will cause erratic flight vertically. Did you do a ladder test or OCW test to see if you are in an accuracy node? You need to do this at 300-600 yards, 100 or 200 yards will not show you a big enough spread to identify an accuracy node.

 

Add a little bit of each of these being off, and it will cause your drop chart to be WAY off.

[AZ_SAWBUCK]

Well I'm surely thinking of variables that I had not yesterday when I was at the range. I have a friend who has a chronograph so I will check velocity and go from there.

 

I'm confident that the range conditions were close to what I entered into the program for temperature, elevation. I don't know how to check barometric pressure.

 

I fine tuned in my sighting in process on the bipod in the same position and range conditions as my 450 yard test.

 

I ranged my target with a Nikon 550 (My rifle hunter 1000 is at Nikon for repair). The range I was shooting at is flat as you can get at 450 yards. Same place I sighted in at. (near the dry lake in Willcox).

 

One ting I'm not sure on is my scope height. What is the best way to check this accurately?

 

10Turkeys? can you elaborate on your comment about the daylight between the end of the scope and the end of the barrel?

 

I'm not going to give up. I think my gun disserves a lot more credit than I have confidence in it right now.

 

 

Thanks for the insight guys! JS

[AZ_SAWBUCK]

O.... I'm positive my Parallax setting was spot on as was my power setting.

 

And that's one heck of a drop tine buck Lance. Thx JS