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Web Clavin Extraordinaire
Picture of Oat_Action_Man
posted
I've seen several people post here the holds for a particular reticle (e.g. an ACSS) tuned to a specific bullet/muzzle velocity, rather than what these are calculated to with factory loads.

What apps/calculators are you all using to do this?


----------------------------

Chuck Norris put the laughter in "manslaughter"

Educating the youth of America, one declension at a time.
 
Posts: 19837 | Location: SE PA | Registered: January 12, 2001Reply With QuoteReport This Post
Freethinker
Picture of sigfreund
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I am probably misunderstanding your question, but if not, and you are asking what ballistics calculators can be used to calculate the holds necessary for various distances and with a reticle calibrated in minutes of angle or milliradians, there are two I’m familiar with.

The JBM calculator is fine, I believe, for most applications not involving extreme long ranges.

https://www.jbmballistics.com/cgi-bin/jbmtraj-5.1.cgi

I also believe, though, that the Applied Ballistics approach is somewhat more accurate because it uses custom drag curves for specific bullets based on actual trajectory analyses. The AB solver has been adopted by a number of manufacturers of things from weather monitors (Kestrel) to rangefinders.

https://appliedballisticsllc.com/ballistics/index.php




6.4/93.6
 
Posts: 47468 | Location: 10,150 Feet Above Sea Level in Colorado | Registered: April 04, 2002Reply With QuoteReport This Post
Bolt Thrower
Picture of Voshterkoff
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I don’t use it (yet) but Strelok Pro is a common recommendation.
 
Posts: 10001 | Location: Woodinville, WA | Registered: March 30, 2004Reply With QuoteReport This Post
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Picture of powermad
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Strelok+ ballistic app has the different reticles.
 
Posts: 1503 | Location: Portland Oregon | Registered: October 01, 2011Reply With QuoteReport This Post
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https://shooterscalculator.com...chart.php?t=3577a961

This is what I've been using.
Plug in what you need.


I'd rather be hated for who I am than loved for who I'm not.
 
Posts: 3652 | Location: The armpit of Ohio | Registered: August 18, 2013Reply With QuoteReport This Post
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quote:
Originally posted by Oat_Action_Man:
What apps/calculators are you all using to do this?

For the ACSS reticle, most ballistics program will produce reasonable numbers. You just need to supply good figures for muzzle velocity, bullet, sight height over bore, and air density (or altitude / temp / air pressure). The ACSS is for reasonable holdover accuracy on moderate-sized targets, not gnat's ass precision on tiny targets. Just find a program that you can easily use.

quote:
Originally posted by sigfreund:
The JBM calculator is fine, I believe, for most applications not involving extreme long ranges.
I also believe, though, that the Applied Ballistics approach is somewhat more accurate because it uses custom drag curves for specific bullets based on actual trajectory analyses.

JBM works quite well for my use. I'm not a true ELR shooter, but dabble in almost-ELR. I think it's important to note that A/B doesn't have drag curves for all the bullets I use -- with some Hornady ELD being a noticeable shortcoming. At least on the A/B web pages I've tried.

JBM does offer the A/B drag curves for some bullets in its drop down menu, and they are generally noted with "Litz" in the bullet description. Compared to the non-A/B curves, the holdover differences can be quite minimal. In a Rifles Only course awhile back, Jacob Bynum (& Lindy) took deep dives into ballistics programs. One comparison was .308 SMK 175, as many students were shooting that. When Jacob ran the A/B (Litz) versus normal JBM data, there was only .1 mil difference in elevation at 1000 yards. He stated that any student who can shoot a .1 mil difference at 1000 yards was welcome to teach the course. He also pulled the A/B data from a Kestrel -- which matched the JBM-Litz data.

JBM .223 data is spot on for my heavy bullet loads to 800 yards -- at which point velocity makes bullet flight less predictable.
JBM .308 data is spot on for my non-168-SMK loads to 1100 to 1200 yards -- at which point velocity makes bullet flight less predictable.
JBM 6mm data is spot on for my match loads to 750 yards -- the farthest I've shot to date.
JBM .300blk data is spot on for quality 110/125 grain loads to 450 yards -- the farthest I've shot to date.
JBM .22lr data is spot on for subsonic 40 grain match ammo to 400 yards -- the farthest I've shot to date.
JBM 9mm data is spot on for my ammo to 200 yards -- the farthest I've shot to date.

JBM 6.5 data for 140 AMax and ELD-M is spot on to 1200 yards. The JBM elevation data is too optimistic beyond that. For most loads I add 1 MOA around 1300 yards, 2 MOA by 1400 yards, and 3 MOA for 1600 yards and farther. This has worked OK in ELR matches when I'm lobbing softballs out to distances beyond the realistic capabilities of a 6.5 Creedmoor. I've hit quite a few targets out to 1800 yards with this method. Just barely missed the 2100 yard target due to windage at the Wyoming ELR match a few years ago with this method.

The few other competitors I've spoken to at ELR matches using 6.5 Creedmoor run into the same issues. IMO the 140 ELD-M doesn't fly quite as well as predicted during transonic and subsonic flight. And it doesn't appear that JBM is the only engine with this issue. Whatever is in Kestrel's engine does the same thing. But the 140 ELD-M does fly nose first at extended distances, and it holds pretty consistent elevation.

JBM doesn't do well with predicting Hornady 6.5 147 ELD-M flight. The BC is noticeably over estimated, and I suspect this is Hornady's fault. Same issue with the engine in Kestrel for this bullet. I know a very talented shooter in Colorado who just gave up on 147 ELD-M in his 6.5 PRC, as the observed BC of the 147 is only marginally better than the 140 grain.

For true ELR shooting, I defer to others with more experience. But I don't recall many shooters using JBM for distances beyond 1 mile.
 
Posts: 7932 | Location: Colorado | Registered: January 26, 2008Reply With QuoteReport This Post
Freethinker
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Thanks for all that discussion, fritz. I know you’ve recommended the JBM calculator before, and I assumed that its results couldn’t be very far off while still remaining in common use, but it’s good to know specifics like that.

I am curious, though, which ELD bullets you haven’t found in the Applied Ballistics library. I use only a few common ELD and other varieties.

I still don’t know if any of this answered the question Oat asked, or if he needs the app that converts the data for specific scope reticles. I checked the Strelok list of reticles for my SAI 6 scope and it wasn’t on it, but I had used the Applied Ballistics solver to come up with what I believe is a conversion set for one type of ammunition that I use.




6.4/93.6
 
Posts: 47468 | Location: 10,150 Feet Above Sea Level in Colorado | Registered: April 04, 2002Reply With QuoteReport This Post
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quote:
Originally posted by sigfreund:
I am curious, though, which ELD bullets you haven’t found in the Applied Ballistics library. I use only a few common ELD and other varieties.

It's been awhile since I've used A/B for ballistics tables. Your A/B link above takes me to a site that doesn't seem familiar -- maybe they changed things a bit. Anyway, I didn't see drop downs for the Hornady ELD-M bullets that I shoot. I did see options for Amax, however. Maybe I'm just not looking in the right place. The ELDs I shoot:
73 grain in .224
105 grain in .244
140 grain in .264
168 grain in .308

I vaguely recall that the Litz data for the Amax bullets produced slightly different data than the regular JBM Amax option. Don't recall one or the other worked better for me.
 
Posts: 7932 | Location: Colorado | Registered: January 26, 2008Reply With QuoteReport This Post
Freethinker
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I purchased the AB solver for my home computer and the drop-down list of bullets under the custom drag curve option does have the three ELD-Match types except for a 105 grain .244 bullet. The closest was 108 grain .243. I don't know how the bullet information may be available otherwise.




6.4/93.6
 
Posts: 47468 | Location: 10,150 Feet Above Sea Level in Colorado | Registered: April 04, 2002Reply With QuoteReport This Post
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Picture of powermad
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quote:
I checked the Strelok list of reticles for my SAI 6 scope and it wasn’t on it


When I was playing around on Strelok I used the Elcan Specter 5.56 BDC reticle for the SAI BDC subtensions, both are in meters.

Just see what the Elcan drop is at 300 and use it on the SAI.
Like so, quick set up with 55gr.
312 meters is a 1.3 mil drop and so on.


The Elcan and SAI are made by the same company so I am assuming they use the same drops as they are both metric.

Seems to hang on till 600 meters then gets a bit more off.
My ACSS is about the same to 500 yds, which is more then sufficient for me.
The farthest I have tried mine is only 200yds though, not much holdover for that.
 
Posts: 1503 | Location: Portland Oregon | Registered: October 01, 2011Reply With QuoteReport This Post
Freethinker
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quote:
Originally posted by powermad:
The Elcan and SAI are made by the same company so I am assuming they use the same drops as they are both metric.

I agree. As I’ve thought on the issue, though, it dawned on me that regardless of variations in reticle markings, the modified drops for different distances and cartridge (load) will be the same, and assuming the reticles are calibrated for the same load at the same distance.

That is, my SAI 6 is (evidently) calibrated for M855 ammunition with a 200 100 meter zero, and has holdover marks for 300 through 800 meters in 100 meter increments. That means if I work out a dope adjustment table for a different load, e.g., Speer 223 Remington 75 grain Gold Dot, then that table will be the same for any reticle with a 100 meter zero and holdover markings in 100 meter increments. I don’t have to find a reticle that’s exactly like mine otherwise.

Although using a solver like the Applied Ballistics requires examination of trajectory figures to convert the holdover marks on the SAI 6 reticle to a different load, it’s an easy process. Because I’ve never gotten into measuring range distances or other calculations in meters, I converted the holdover values to yards at the same time. And now I’m curious whether the Strelok app will also convert a reticle calibrated in meters to values for yards.

Thanks for that.

Edited to correct my statement about the SAI 6 reticle zero.

This message has been edited. Last edited by: sigfreund,




6.4/93.6
 
Posts: 47468 | Location: 10,150 Feet Above Sea Level in Colorado | Registered: April 04, 2002Reply With QuoteReport This Post
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You can change it to yards.

200 yds is the zero?
If I am reading the subtensions correctly E = 2.64 mil.
Which the bottom is the 300 meter line.
Half of that is 1.3 mil, which is the drop from a 100 meter zero according to the app.
 
Posts: 1503 | Location: Portland Oregon | Registered: October 01, 2011Reply With QuoteReport This Post
Freethinker
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quote:
Originally posted by powermad:
200 yds is the zero?

Hmm …. I had convinced myself that the BDC reticle was based on a 200 meter zero, but your question convinced me to double check and it’s actually based on a 100 meter zero.

I’ll have to redo my calculations, but it was mostly a proof of theory exercise. Using the scope beyond 200 yards isn’t something I’m planning to do except to confirm that my calculations for the 300 meter and beyond aiming marks are correct. But one thing about developing dope tables for different loads is that the loads can be zeroed at whatever distances are convenient.




6.4/93.6
 
Posts: 47468 | Location: 10,150 Feet Above Sea Level in Colorado | Registered: April 04, 2002Reply With QuoteReport This Post
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I have three loads that are zeroed at 100 yds.
77 and 55 is .5" high at 100 yds and 62 has a zero offset.
With that it should have solid A zone hits to 500 yds.
 
Posts: 1503 | Location: Portland Oregon | Registered: October 01, 2011Reply With QuoteReport This Post
Freethinker
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One thing that becomes clear when working with a ballistic solver is that the trajectories of many 223/5.56 loads are similar enough that their differences have little practical effect on engaging human-sized targets to several hundred yards.




6.4/93.6
 
Posts: 47468 | Location: 10,150 Feet Above Sea Level in Colorado | Registered: April 04, 2002Reply With QuoteReport This Post
Web Clavin Extraordinaire
Picture of Oat_Action_Man
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So Strelok+ is the app I was looking for.

Went and downloaded it and...whew, that's a lot. Seriously, are there instructions??? I'm a dolt. Eek

I think came up with a solution for the SFP ACSS 1-6x 300 BLK reticle for my 9" MCX using Gorilla's 110gr TAC-TX load. When I chrono'ed it myself, I got a 5 round avg MV of 2030 fps from my 9" barrel (suppressed). Gun is zeroed at 50 yds at 6x, per the Primary Arms instructions.

The bullet library didn't have the Barnes TAC-TX so I had to choose the 110gr TAC-X.

The reticle Strelok provided seems reasonable for the load out of a short barrel (50 at the tip of the chevron, 145 at the inside vertex of the chevron, 456 at the 600 yard hash), but I'm largely out of my depth here.

Some questions:

Did I totally mess that up?

How do I actually get it to input an avg velocity of 2030 fps? It requires 2 velocities and somehow spits out 2018 fps??

Did I miss the TAC-TX in the bullet library?

What's G7 vs. G1 coefficient? I used the latter.

What's my far zero? It doesn't seem to list anything on the reticle (aside from 50 yds tip of chevron) and I don't see a full ballistic table option anywhere.

Is there a gun/reticle/load library I can save this solution to? I send a pic of the reticle to myself, but inputting the data is a pain.

Is there an instruction manual? I didn't see anything in the settings menu....


----------------------------

Chuck Norris put the laughter in "manslaughter"

Educating the youth of America, one declension at a time.
 
Posts: 19837 | Location: SE PA | Registered: January 12, 2001Reply With QuoteReport This Post
Freethinker
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quote:
Originally posted by Oat_Action_Man:
What's G7 vs. G1 coefficient? I used the latter.

Hopefully you’ll get answers from those who are familiar with the Strelok, but regarding the coefficients:

G1 is based on an old bullet design that has a pointed but somewhat blunt nose and flat base. G7 is considered to be more representative of modern bullets with longer noses and boattails. Assuming I found the bullet you’re using, either is probably fine, but I always use G7 when possible and I can’t use a custom drag curve. On the other hand the G1 is often cited by manufacturers for their bullets because the raw numbers are larger than the G7 figures, and (IMO, of course) that’s to mislead the ignorant. As I understand it, the difference between G1 and G7 figures doesn’t matter much, if at all, except at very long ranges.

I assume you’re trying to determine where your load would strike at the different ranges marked on the reticle—correct? If so, it would be possible to use a ballistic solver to do that, but we’d have to start with how the reticle was calibrated by the factory. I think I see that, though, in the instruction manual for the scope that lists various loads that I assume correlate to the factory calibration, correct?




6.4/93.6
 
Posts: 47468 | Location: 10,150 Feet Above Sea Level in Colorado | Registered: April 04, 2002Reply With QuoteReport This Post
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I just played around with it and learned as I went.

Select rifle in the middle.


Select change rifle.


Up to 10 rifles can be stored.


Select cartridge 1


Enter data.
I went to the web site and got the BC of .293 G1
https://www.gorillaammo.com/wp...Sheet-GA300110NV.pdf


Select the scope.
I used a 100 yd zero and a scope height of 2.62" assuming you have a 1.5" mount.


Range 200 yds


Another neat feature is you can slide the power 1 - 6 and see the different POI
25 yds at 1x
 
Posts: 1503 | Location: Portland Oregon | Registered: October 01, 2011Reply With QuoteReport This Post
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Picture of powermad
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Inside bottom of chevron is 2.2 MOA
Bottom of the chevron is 4.86 MOA
Top of post is 5.95 MOA
9.41
11.3
13.31
17.64
21.62
25.39
 
Posts: 1503 | Location: Portland Oregon | Registered: October 01, 2011Reply With QuoteReport This Post
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Also keep in mind that the ACSS reticle is calibrated for ammo with a MV of 2250 - 2450 FPS
At 2030 it will be different than their chart.

But with the app you can play with the zero and come up with your own that will work.
 
Posts: 1503 | Location: Portland Oregon | Registered: October 01, 2011Reply With QuoteReport This Post
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