Shot at 808 yrds and need help........

[rscott5028]

The OP didn't say what bullet. Some have had independent confirmation of the BC, G1 and/or G7.

Little details like scope height can be a factor.

Your chrony may not be calibrated, or may be off due to lighting conditions.

You didn't indicate how close the actual MV of the fired shot was relative to the MV used to calculate your come-up. i.e. Using MV from a small sample with a high SD may not be a good predictor of actual performance. Hence, the recommendation to shoot 3 shots.

3 is better than one shot by far. But many 3 shot groups, or a 20 shot string if the rifle is setup for it, will continue to give better confidence as to repeatability.

Multiple groups at varying ranges may indicate a trend as to what input may need tweaking to develop a decent drop chart.

-- richard

 

[Scot E]

After all these little details are worked out and verified with the ballistic program, settings, etc. I would go find a shooting area where you can get setup for shots from 700 yards out to the furthest you think you will shoot. It is important to go that far out because inside of 6-700 yards it is tough to see much difference in POI due to your velocity being off. I would then pick 3 or 4 distances in between and shoot 3 shot groups for each.

These days I mess less and less with a chronograph. I will use one to get me in the ballpark but then I go directly off my validation groups POI. So I take the center of the groups I shot and measure how far off they were to center and then if my ballistic app has a validation too I will use that to come up with the correct velocity. If no tool then I start messing with the velocity until I get my drops as close to correct as possible. You can also tweak the BC very slightly then go back to velocity to see if that doesn't get things dead on.

Scot E.

 

[bigbuck]

After all these little details are worked out and verified with the ballistic program, settings, etc. I would go find a shooting area where you can get setup for shots from 700 yards out to the furthest you think you will shoot. It is important to go that far out because inside of 6-700 yards it is tough to see much difference in POI due to your velocity being off. I would then pick 3 or 4 distances in between and shoot 3 shot groups for each.

These days I mess less and less with a chronograph. I will use one to get me in the ballpark but then I go directly off my validation groups POI. So I take the center of the groups I shot and measure how far off they were to center and then if my ballistic app has a validation too I will use that to come up with the correct velocity. If no tool then I start messing with the velocity until I get my drops as close to correct as possible. You can also tweak the BC very slightly then go back to velocity to see if that doesn't get things dead on.

Scot E.

Great! thanks for taking the time to break it down for this hill billy

I am running the berger 210 hunting VLD .631 Bc

original MV started at 2922 FPS CDM chrony.

I am ready to give it another try.

Thanks again.

 

[Trickymissfit]

Great! thanks for taking the time to break it down for this hill billy

I am running the berger 210 hunting VLD .631 Bc

original MV started at 2922 FPS CDM chrony.

I am ready to give it another try.

Thanks again.

I have found that in more cases than not, the so called ballistic coefficient stated is often pure guess work. Much like pretty colored fishing lures are made to catch fishermen. If your certain about the velocity your getting (I'm not doubting you in the slightest), and you shooting parallel with the earth; then go back to your figures and recalulate to where you are seeing the same trajectory you are getting. Lastly those clicks in elevation are rarely exact, and you can only tell by doing a box test at 100 yards to be sure. I suspect the 5" of drop is a combination of several small things that add upto something much bigger.
gary

 

[bigbuck]

I have found that in more cases than not, the so called ballistic coefficient stated is often pure guess work. Much like pretty colored fishing lures are made to catch fishermen. If your certain about the velocity your getting (I'm not doubting you in the slightest), and you shooting parallel with the earth; then go back to your figures and recalulate to where you are seeing the same trajectory you are getting. Lastly those clicks in elevation are rarely exact, and you can only tell by doing a box test at 100 yards to be sure. I suspect the 5" of drop is a combination of several small things that add upto something much bigger.
gary

"sever small things that add upto something much bigger"

True, It isnt so easy to make anything full proof at extended ranges . Im determined to get this down tho and it helps to see other folks doing it !

 

[Bart B]

Exbol said I should dial 15 MOA up. fired one shot
Drove out to the target and ended up 5.410 inches low.

Now my question is this what should the correction( Target Validation) in MOA be to get me dead center at 808 ? New MV ?

I've been on of the top long range competitors in the USA shooting on the US Palma Team as well as other international and national teams. Every one of the highest ranked folks would throw a party if their first shot at 800 yards was no worse than 5.41 inches off from point of aim. It that miss distance is what you got, welcome to the club. Ignore folks who get concerned about muzzle velocity, atmospheric conditions, rifle or ammo issues and the like. Us humans are the biggest variable in this venue so pay attention to folks suggesting you shoot a few more rounds at that range to see what reality is. A 3 shot group's going to have a 50% probability of indicating where all the first shots will go. Shoot a 20 shot group and you'll have an 80% probability. You get to decide how reliable your data is.

It's very normal for the first shot from a clean barrel to go about 1/4 to 1/2 MOA low at long range. All of my long range match rifles do that. Ammunition's just like people; don't judge its performance by what only one does.

 

[bigngreen]

Ignore folks who get concerned about muzzle velocity, atmospheric conditions, rifle or ammo issues and the like.

No wonder you would get excited about being within 1/2 MOA!!

 

[Scot E]

I've been on of the top long range competitors in the USA shooting on the US Palma Team as well as other international and national teams. Every one of the highest ranked folks would throw a party if their first shot at 800 yards was no worse than 5.41 inches off from point of aim. It that miss distance is what you got, welcome to the club. Ignore folks who get concerned about muzzle velocity, atmospheric conditions, rifle or ammo issues and the like. Us humans are the biggest variable in this venue so pay attention to folks suggesting you shoot a few more rounds at that range to see what reality is. A 3 shot group's going to have a 50% probability of indicating where all the first shots will go. Shoot a 20 shot group and you'll have an 80% probability. You get to decide how reliable your data is.

It's very normal for the first shot from a clean barrel to go about 1/4 to 1/2 MOA low at long range. All of my long range match rifles do that. Ammunition's just like people; don't judge its performance by what only one does.

Could you explain the portion of your post above that I bolded. It surprises me to her a shooter with your qualifications give this kind of a response. Maybe I am misreading your point? MV, atmospheric conditions make huge differences in POI vs POA and the further you shoot the more important nailing down that data is. I get your point about understanding group size at various distances and how your expectations should correlate to it but to ignore the above mentioned seems curious to me. The reality is that he could have some turret error, some velocity error, some bc error, and some atmospheric error and they are all counterbalancing each other to some extent and in this particular situation he is getting pretty consistent POI compared to his drop chart. But on a different day at a new location with new conditions he is way off. Until you nail down all the errors I don't see how you can expect any kind of consistency in the LR hunting game. This one shot deal, the LR hunting game is quite different than many shooting competitions where you get to dial in your loads then shoot for groups. Maybe that is where I am misunderstanding.

Thanks,

Scot E.

 

[Bart B]

Could you explain the portion of your post above that I bolded.

For all I know, that single shot's the bottom one of a 1 MOA many-shot group that he and his rifle's capable of. I qualify this by my earlier comment that the first shot from a clean bore can go that low at 800 yards. Therefore, the center of several shots fired afterwords may well center exactly on his point of aim.

 

[bigbuck]

For all I know, that single shot's the bottom one of a 1 MOA many-shot group that he and his rifle's capable of. I qualify this by my earlier comment that the first shot from a clean bore can go that low at 800 yards. Therefore, the center of several shots fired afterwords may well center exactly on his point of aim.

I have a broughton barrel and they told me to clean every 20 to thirty rounds and that during hunting season never go into the woods with a clean barrel .

A little more info . My scope is a 5.5X22X56 NF mounted atop of NF ultra lite rings and NF rail . So far when you adjust it moves impact 200 yards out to 808.

 

[Bart B]

A little more info . My scope is a 5.5X22X56 NF mounted atop of NF ultra lite rings and NF rail . So far when you adjust it moves impact 200 yards out to 808.

Have your ever shot a 10-shot group with it at long range to see where the last 8 go compared to the first two?

Have you calibrated the adjustments on your scope to see exactly how far they move per click? That is, how far does the reticule move on a ruler at 100 yards if you move the adjustment a given number of clicks. I don't know what your adjustment value is 'caujse NF's web site ain't all that exact. It's either 1/4 MOA (angle or inches per hundred yards?) or 1/10th mil which is exactly .36" at 100 yards but that scope can have as much as a 5% error; hopefully not any more than that.

If it's got a bullet drop compensation adjustment, it's fixed for only one altitude, bullet, muzzle velocity and atmospheric conditions. It may not be calibrated for your equipment and use.

Good data on these things will make it much easier to move from a short range to a long range and have real info on where that first shot at long range will go; from both a dirty and clean barrel.