Thread: Difference between ballistic chart and real word results

1st of all, is your scope tracking accurately? And is it properly levelled
2nd is your BC right (yes if you are using litz BC with same twist barrel)
3rd, is your velocity correct? If using an optical chrony, id look at this 1st after making sure the scope is right.

Can only be those things, unless you are shooting steep up or downhill

I get 7.89 moa for 400 yards with a 100 yards zero, assuming you have a 9.5 twist i get a stability of 1.45 which is propably OK but they dont reccomend going under 1.5

Personally ive gone to 1.3 and have been all good out to 1000 yards

This was using the applied ballistics app and the listz G7
And just my local atmospherics, but that wont matter heaps between AKL and Hams at 400 yards

Greetings,
The key is everything must be the same. If you shoot in the field prone with a bipod then your 100 yard (200 yards would be better) zero should be prone with a bipod. I have been on rather a steep learning cure recently with F class shooting. For setting up my rifles for 300 and 600 yards they are shot at 200 metres with the predicted impact from my ballistic chart marked on the target. This is based on chronographed velocity and published BC. I assume that you have checked the actual value of your scope clicks. Many scopes vary from what is marked on them. I think a lot of shooters kneecap themselves doing a base zero at 100 metres or worse yards. The other thing that can be out is the rangefinder. Some chronographs can be dodgy but mine is a 35P which measures the velocity twice using a 3 screen set up and my predicted 600 yard velocity is bang on with that measured by the range software. There are a bunch of things that should be checked before entering bullshit velocity in your app. This will just bite you on the arse further out.
One last thing. Are you aiming marks good enough to be able to precisely aim at each range? Many are not.
Regards Grandpamac.

This all goes to show that theory is pretty good, but not infallible. There are far too many variables to take into account (wind, temperature, humidity, altitude, barrel manufacturing tolerances, bore wear, case neck tension, case manufacture tolerances, chamber dimensions, etc.) that make it impossible for theory to be exact, just near enough. The exact results can only be ascertained by actual shooting, bearing in mind that there are even more variables to consider to achieve consistent results. Top-level target shooters only seek to minimise the variables on any given day as they realise that it is impossible to eliminate them.

Originally Posted by Sikahunter262

I am shooting a 7mm08 17 inch barrel with handloaded162 Eldms. 41.5gr of 2208.

I have chronographed the load and have a speed of 2575fps which I thought was about right. Gun is zeroed at 100y.

I have just got a sew set of swaro rangefinding binoculars which when shooting at 400 yards showed a dial up on 7.5 MOA. Of interest was my strelok app showed the same.

Now when shooting my impact was around 6 inches high. 6.25 brought it back down to bang on. Only thing is for me to get the binos reading that MOA I had to enter a speed of 2750fps which seems a bit too fast.

Thoughts?

I have just got a new pair of range

Suspect the reticle on the EL Range is not exactly dead centre of where the beam is hitting.

Try getting your binos really stable, rested on something so you are not physically holding them up. A tripod is ideal but can be done with a backpack.

Now, range a very definite target which is only slightly bigger than the reticle, and nake sure its dead centre. Then turn your binos upside-down, and sideways, and repeat.

If you arr getting wildly different readings, keep trying using different areas of the reticle (12 oclock, 3, oclock, 6 and 9) until you get a more consistent reading.

Been seeing this quite a lot with rangefinding binos, even top end ones. Much prefer a dedicated handheld unit as they are much less prone to this issue.

Anyway, very simple ballistic chart.

If you have a rifle shooting a projectile with a 0.5-0.6 G1 BC and a muzzle velocity between 2,600 to 2,800 fps, the following should apply with a scope in Mils.

100 yard zero

200 yards 0.5 Mils

300 yards 1 Mil

400 yards 2 Mils

500 yards 3 Mils

600 yards 4 Mils

You might have to adjust between 0.2 to 0.3 mils (usually add) at 400 yards plus, but usually this is very close.

With your setup, I'd say the call of 7.5 MOA is more likely to be correct for 400 yards vs. 6.25, to make it easier, refer to this quick MOA to Mils chart:

https://docs.google.com/spreadsheets...mFqIo/htmlview

So, to keep it simple, potential list of issues, in order of likelyhood:

1. Your binos are not ranging correctly

2. Your scope is not dialling accurately, is it a Leupold...?

3. Your zero is off

4. Your chrono data is off (unlikely as it sounds about right with your setup).

Scope height only affects maximum point blank range, not the external ballistics of the bullet, and is a subject best left for now.

Originally Posted by caberslash

Suspect the reticle on the EL Range is not exactly dead centre of where the beam is hitting.

Try getting your binos really stable, rested on something so you are not physically holding them up. A tripod is ideal but can be done with a backpack.

Now, range a very definite target which is only slightly bigger than the reticle, and nake sure its dead centre. Then turn your binos upside-down, and sideways, and repeat.

If you arr getting wildly different readings, keep trying using different areas of the reticle (12 oclock, 3, oclock, 6 and 9) until you get a more consistent reading.

Been seeing this quite a lot with rangefinding binos, even top end ones. Much prefer a dedicated handheld unit as they are much less prone to this issue.

Anyway, very simple ballistic chart.

If you have a rifle shooting a projectile with a 0.5-0.6 G1 BC and a muzzle velocity between 2,600 to 2,800 fps, the following should apply with a scope in Mils.

100 yard zero

200 yards 0.5 Mils

300 yards 1 Mil

400 yards 2 Mils

500 yards 3 Mils

600 yards 4 Mils

You might have to adjust between 0.2 to 0.3 mils (usually add) at 400 yards plus, but usually this is very close.

With your setup, I'd say the call of 7.5 MOA is more likely to be correct for 400 yards vs. 6.25, to make it easier, refer to this quick MOA to Mils chart:

https://docs.google.com/spreadsheets...mFqIo/htmlview

So, to keep it simple, potential list of issues, in order of likelyhood:

1. Your binos are not ranging correctly

2. Your scope is not dialling accurately, is it a Leupold...?

3. Your zero is off

4. Your chrono data is off (unlikely as it sounds about right with your setup).

Scope height only affects maximum point blank range, not the external ballistics of the bullet, and is a subject best left for now.

Greetings,
Some very good points in this post. Thanks @caberslash. Checking the accuracy of the readings from a rangefinder may not be as tricky as it sounds. Our local Council plus many others has a GIS system for land information which is available on their web site website. This includes Cadastral info, property boundary measurements and such plus aerial photos with decent detail. Ours also has a distance tool that allows you to measure the distance between two points with a couple of mouse clicks. I use it quite a bit so have a look on your local Council web site to see what is on offer. I checked the length of one of our boundaries which is a little under 400 metres with the distance tool and found the latter to be quite accurate. You may also be able to use the GPS coordinates on the GPS app on your bat phone to check the distance but this may need some Geometry to calculate. Have not tried this one yet.
Regards GPM.

I had the same problem with a swarovski z3 once. I'm guessing the clicks weren't calibrated to exactly moa

Originally Posted by Gkp

I had the same problem with a swarovski z3 once. I'm guessing the clicks weren't calibrated to exactly moa

From people in the know it used to be only Nightforce that had perfectly calibrated adjustments and from what I have seen from other high-end optics I tend to agree.


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