Confirming Drops

[Scot E]

I think one of the most overlooked factors when real life ballistics don't match up with computer charts is the turret accuracy per click. Not many people check to make sure each click is .25 MOA or .1Mil etc. Most of my scopes are a bit off and at distance it makes a difference. There can be lots of other reasons too but this one is most overlooked IMO.

Holland's Gunsmithing & Shooters Supply -click on articles then "Houston we have a problem". This article does a nice job of explaining one method of checking click value. the reticle perpendicularity article is also good.

 

[4xforfun]

4Xforfun,

Curious what you would use for a target when measuring actual drops at 800? I would need some sort of target that was 9 or 10 feet tall to do that with a 300 yd zero.........I don't have any cardboard or posts that tall, LoL.

On another note, if when you shoot at 100 you discover that 30 moa is actually moving poi by 32 moa (just as an example) would you replace the scope or send it back? Or, would you try to tweak the program to match your true click values?? I am curious, because the rifle I mentioned may have a scope issue...??...too early to say for sure.

With the Berger 210 VLD, with a 300 yard zero, and guns with velocitys between 3000 and 3220, I will need between 96" and 110" at 800. My regular targets are 4x4 sheets of plywood on 8 foot tall legs....portable, of course. I will just tack a sheet of plywood with an extra 2 foot long pice of 1x4 tacked on top of the plywood with an aim point on it. I usualy tack some freezer paper on the plywood...you can see the hits along way off.
I wish I could figure out how to attach pictures.......my target system and sighter target work great. I use them out to 1200 yards on my home range. Very portable. No guesswork on where your impacts are at LR!!!

As far as the scope issue...I guess I havn't thaught that far ahead. I am not sure if the nightforce scopes' adjustments are in inches or true MOA. No biggy at short range, but may come into play at the extream ranges. I just havn't done the math on it. I think that the Infinity program can switch between inches and MOA........I THINK.

 

[Scot E]

With the Berger 210 VLD, with a 300 yard zero, and guns with velocitys between 3000 and 3220, I will need between 96" and 110" at 800. My regular targets are 4x4 sheets of plywood on 8 foot tall legs....portable, of course. I will just tack a sheet of plywood with an extra 2 foot long pice of 1x4 tacked on top of the plywood with an aim point on it. I usualy tack some freezer paper on the plywood...you can see the hits along way off.
I wish I could figure out how to attach pictures.......my target system and sighter target work great. I use them out to 1200 yards on my home range. Very portable. No guesswork on where your impacts are at LR!!!

As far as the scope issue...I guess I havn't thaught that far ahead. I am not sure if the nightforce scopes' adjustments are in inches or true MOA. No biggy at short range, but may come into play at the extream ranges. I just havn't done the math on it. I think that the Infinity program can switch between inches and MOA........I THINK.

And what you often find is even if you figure out whether your scope turret adjusts in inches or MOA, the nightforce is MOA, you will also still find that a click of the turret that is supposed to move your reticle .25 MOA may in fact move it .24 or .26, etc. This is the error i was talking about.

 

[4xforfun]

And what you often find is even if you figure out whether your scope turret adjusts in inches or MOA, the nightforce is MOA, you will also still find that a click of the turret that is supposed to move your reticle .25 MOA may in fact move it .24 or .26, etc. This is the error i was talking about.

Yep, this I understood....like I said...I havn't thought that far ahead. It is to close to season to send anything in now. And if it is as little as .24 -.26 instead of .25...well that is only 4%....8" at 1K..... I think I could tweek the FPS of BC to correct for that. As long as everything is repeatable.

 

[Scot E]

Yep, this I understood....like I said...I havn't thought that far ahead. It is to close to season to send anything in now. And if it is as little as .24 -.26 instead of .25...well that is only 4%....8" at 1K..... I think I could tweek the FPS of BC to correct for that. As long as everything is repeatable.

Ok, just making sure I was being clear on what I was trying to say.

I have actually seen quite a few scopes be further off than .24 or .26 (just used those as an example) so it can be much worse.

Most ballistic programs have a place to adjust for actual click value so the adjustment can be made where it should be, avoiding having to mess with changing correct BC or velocity numbers.

Good luck!

 

[eddybo]

tall targets are a great way to determine whether your scope dials correctly. measure your drops, convert to moa, dial that into your scope, use the bullet hole that you measured to as your new point of aim, if verticale is correct your scope dials are gtg.I always sigh my rifles in at long range then set my dials to match my trajectory data, then dial back to confirm my 100 yard zero. if you do that after you have confirmed your drops at numerous ranges and tweaked your data to match your actual drops it can minimize errors in scope calibrations.

 

[RMulhern]

Afix a steel tape to a wall a MEASURED 300' distance. Put the rifle/scope in a SOLID CRADLE! Put the vertical wire on a specific location and count clicks! If 1/4 MOA movement....4 clicks should move 1"! This has to be done out to the extremity of reticule movement because many scopes will bind up or stop moving at the upper end of movement! And one MOA movement IS NOT ONE INCH; rather slightly over at 1.047"! This makes a difference at LR! Check it out!lightbulb

 

[4xforfun]

Ok, just making sure I was being clear on what I was trying to say.

I have actually seen quite a few scopes be further off than .24 or .26 (just used those as an example) so it can be much worse.

Most ballistic programs have a place to adjust for actual click value so the adjustment can be made where it should be, avoiding having to mess with changing correct BC or velocity numbers.

Good luck!

I have the Sierra infinity 5 program. I looked around for a place to tweek the "click value's"....can't find any place. Is it there and I missed it?

 

[Scot E]

I have the Sierra infinity 5 program. I looked around for a place to tweek the "click value's"....can't find any place. Is it there and I missed it?

I don't use Sierra's program but I know it is hugely popular. I can't imagine it wouldn't have it. Many of the ones you download have it. The software located on the LRH home page has it. I think that is nightforce's program.

 

[SBruce]

I've got the NF program on PC. In the field we were using the same program on a PDA.

The PC version and PDA version don't exactly match (close, but up to 1/2 moa different) concerning the 338 EDGE. There is also a feature that doesn't work at all on my PC version but does work on the PDA one, it's the Trajectory Validation option, which we used on the PDA......perhaps why they didn't exactly match??

The NF PC program has a spot to change the click values (sight adjust option, custom), but when done; it doesn't change the amount to dial in, UNLESS you check the box saying "show total clicks" ............then it will change the amount of clicks needed to reach the same total drop, but shows this in clicks, NOT moa.........unsure if the PDA version has this option?

Example: 21.34 moa drop at 950 yds (212") is 85 clicks (assuming .25 moa/click)
Same drop at 950 with .27 moa clicks is only 79 clicks.............Real World, we had 76 clicks in and were still hitting a foot high on paper at 950.

I am unsure how the newer Sierra program works, I've got an older version (version 2.2 I believe) and it doesn't agree with the NF program on drops (shows 2" more at 950 yds with input all parameters the same) so I've kinda quit using it for the time being.

 

[4xforfun]

SBruce,

I wouldn't get overly excited about a 2 inch discrepincy between the two programs at 950 yards!! I don't think I can hold that close in field, real world conditions.

 

[SBruce]

Truth be told, I can't hold that well under field conditions either, but since the NF program is newer than my old sierra stuff......figured it may be a little more accurate (updated Bullet files, BC's and such) For all I know, the newest Sierra program is the cat's meow!?

I haven't found anyplace to change click values on the old Sierra program though either.

 

[BountyHunter]

I think one of the most overlooked factors when real life ballistics don't match up with computer charts is the turret accuracy per click. Not many people check to make sure each click is .25 MOA or .1Mil etc. Most of my scopes are a bit off and at distance it makes a difference. There can be lots of other reasons too but this one is most overlooked IMO.

Holland's Gunsmithing & Shooters Supply -click on articles then "Houston we have a problem". This article does a nice job of explaining one method of checking click value. the reticle perpendicularity article is also good.

+1

I would venture that 70-80% of the so called variances in BC and MV etc are actually due to click variations on scopes that the shooter "assumes" are what they say.

Dan Lilja also has written on how to do it and said this is the first thing to confirm.

BR central shooters just started a thread on this where the originator discovered his NF was actually .28 inch instead of .25

BH

 

[Scot E]

+1

I would venture that 70-80% of the so called variances in BC and MV etc are actually due to click variations on scopes that the shooter "assumes" are what they say.

Dan Lilja also has written on how to do it and said this is the first thing to confirm.

BR central shooters just started a thread on this where the originator discovered his NF was actually .28 inch instead of .25

BH

I have seen click values as low as .19 and as high as .32 for a .25 MOA scope. Most are less than this but it does show you how bad it can be. Interesting on the NF. It would also seem prudent to re-check over time, especially for those that really give their turrets a lot of use by dialing for each distance they shoot. I would think some wear of the turret gearing could change values over time as well.