Rifle Scopes Checking to see if my scope has enough adjustment for 1400 yards, please confirm my calculation thanks

[want2learn]

I have signed up for a class that reportedly will shoot up to 1400 yards.

I purchased an Athlon Ares BTR 4.5-27x50 rifle scope with an APLR3 FFP IR MIL reticle and my Sig SSG3000 i believe has a flat 0 MOA rail.

I counted up the full elevation range of clicks from one extreme to the other and it was a total of 211 clicks.....so i should have a total of 21 MIL range if i start at the very bottom of the range. I would imagine it would be best to start from the middle of the adjustment range but that's not what i have available to me.

I'm shooting a 6.5x47 Lapua with factory 139gn ammunition as the class won't permit reloads.

My calculation says it should take me 10.4 MIL to reach 1000 yards and 20 MIL to reach 1400 yards if i'm shooting 2600 fps at sea level

....so i think my available 21 MIL total range should suffice. Does this sound correct? thanks

 

[HiDesertELR]

Short answer, no.

Read this, it'll explain it all:

How to figure the correct MOA angled scope mount base....

These questions seem to come up a lot with the rise of people shooting .22LR out to 200, 300, 400+ yards.... Do I need a 0 MOA, 20, 30, or 40 MOA scope mount base ??? Can I still get a 25 or 50 yard zero??? How far will I be able to dial with XX scope and XX MOA base??? This depends on 4 main...

www.snipershide.com

 

[Tim_WNC]

You need to know how much of that elevation is 'used up' getting to your 100yd (or whatever) zero, then figure your required adjustment after zero.

So...if you need ~8mil of adjustment to get to zero, then need +20Mil of adjustment to get to 1400, you need a total of 28Mil adjustment.

 

[Rocketvapor]

Where does it point when turned to the bottom of the range?
Where does it point when turned to the middle of the range?
How much hold over does the reticle give when at max up?

Do you have enough time to fit a 20MOA rail and test fire?

 

[Sixfivesavage]

You're going to a class that runs out to 1400 yds and requires factory ammo....?

 

[Long Range 338]

Ok, so next time you ask a question please provide your rifle and load specifics..... After doing some homework to research your load and enter it into a ballistic calculator and assuming atmospherics, rifle setup, scope height, etc. JBM says 17.8 mils to 1400 and 20.5 mils to reach 1500 yards. You are going to need as much of that internal travel as you can get. I'm sure the link above provides the info to convert. I guesstimate you need the 40 moa offset

 

[want2learn]

thanks.....i really appreciate it. i neglected to factor in the 100 yard zero. good lesson.

The new scope is not yet mounted, just took it out of the box to do this preliminary set of calculations.

Will have to take out the rifle and see how the rail is mounted, I can't recall if the rail is fixed or screwed on. I'm not even sure if anyone makes a rail for it as the rifle is no longer supported by U.S. Sig Sauer.

I do have a first generation Sig tango6 3-18x MIL scope on the rifle now so at least i have something to use but thought perhaps the wider magnification range of this new scope might be nice to try.

I recall that Burris makes rifle scope rings that have inserts that might buy me some cant if i'm unable to get a different rail.

 

[want2learn]

Long Range, i'm sorry..... i did post that it was a Sig SSG3000 that i'm running a 6.5x47L with factory 139 gn ammo that yielded a velocity of 2600fps on my test at sea level. The calculator i used was called GeoBallistics but maybe i didn't use it correctly. I don't have JBM but perhaps i should get that one. Will see if i can get a different rail or if Burris has inserts that will work. Still learning and appreciate the help.

 

[Rocketvapor]

On line JBM calculator is useful.
My guess is your scope will be NEAR center for a 100 yd zero, or a 200 zero.
Scopes like to be centered.
You will probably have 11 or 12 mils remaining.
Your reticle has about 10mils.
A 20MOA rail or riser will likely get you really really close.
A 30 MOA rail would be close to centered @1000 and still allow you to zero @ 100.

 

[Long Range 338]

Not a big deal, just slows the process to help as I had to search out the factory load data, bc, and make assumptions about the atmospherics. Also I calculated from the Lapua stated velocity of 2690fps so you would have even more drop. JBM ballistics is a free webpage you can use for this type of stuff, just google it.

EDIT: I tried to confirm with Hornady's webpage calculator but it was WAY off. Applied Ballistics free online calculator was almost exactly the same as JBM

 

[want2learn]

thank you, learning a lot.

 

[Rocketvapor]

If the troubleshooting threads here are examples of reloading woes, factory ammo in a CLASS eliminates most stuck cases, blown up guns, and other delays like waiting for the med evac

Get that scope mounted really well, and zeroed.
Waiting for the last person to get on target is a drag.
Don't be that person

 

[Kickin45]

Nope. On a 0 cant mount, your going to use a lot of your available
Elevation just to zero the scope.
Get a 20moa mount

 

[Steel head]

In all probability you’ll have half of your total elevation available to you on a 0 rail/mount.

with a 20 moa rail/mount you’ll have approximately 16 mils useable elevation.

with a 30 moa rail/mount you’ll have approximately 19.

 

[spife7980]

The calculator i used was called GeoBallistics but maybe i didn't use it correctly. I don't have JBM but perhaps i should get that one.

Just as an FYI, geoballistics uses the JBM engine.

Ares BTR has 24 mils of adjustment, thats 12 up and 12 down. Where you are zeroed will change that actual amount avaliable but it shouldnt be a whole lot different.

So you can get to 1,000 yards alright, its going past that where its 2.5 mils more with each subsequent 100 yards that youre going to fall off the rails reaching your loftier goals. Not to mention that you are going to be going transonic right around 1100 yards and subsonic at 1300, lets hope the scenars transition smoothly. A better (higher bc) bullet will only help.



Tell your instructor that factory ammo only is the reason Im not coming along too.

 

[Tim_WNC]

Long Range, i'm sorry..... i did post that it was a Sig SSG3000 that i'm running a 6.5x47L with factory 139 gn ammo that yielded a velocity of 2600fps on my test at sea level. The calculator i used was called GeoBallistics but maybe i didn't use it correctly. I don't have JBM but perhaps i should get that one. Will see if i can get a different rail or if Burris has inserts that will work. Still learning and appreciate the help.

You provided everything needed to answer the question.

Not a big deal, just slows the process to help as I had to search out the factory load data, bc, and make assumptions about the atmospherics. Also I calculated from the Lapua stated velocity of 2690fps so you would have even more drop. JBM ballistics is a free webpage you can use for this type of stuff, just google it.

EDIT: I tried to confirm with Hornady's webpage calculator but it was WAY off. Applied Ballistics free online calculator was almost exactly the same as JBM

He said in the OP that he needed 20Mil to get to 1,400. And provided the range of travel for his optic? Why blast him for not providing all of those details? They aren't actually relevant to the question.

 

[Steel head]

Tell your instructor that factory ammo only is the reason Im not coming along too.

Lol!

 

[Rocketvapor]

Lol!

So, if they allowed reloads you would go to the class?

If the instructor was good he could troubleshoot the reloads for free.
Maybe the class should have SH on quick dial to ask why their reloads wont chamber.

Or a remedial class.
Or send them home if the reloads don't work.

Most of the class will probably be at lesser ranges.
I suggest a 224V, makes it to a mile ( I read somewhere someone did that)
Or maybe it's big brother

 

[Lowlight]

It's not about being good and troubleshooting reloads,

As an instructor, reloads in the wrong hands can be a big issue for a class. This past year we had a guy come to class with "purchased" reloads for his 30-378. During our fundamental Eval before class even started I said to Marc, "this guys gun is gonna blow up in 10 rounds" it took 8 rounds to break the bolt.

It's not about diagnosing a problem, it's about safety and downtime, and the fact you just don't know enough about the person reloading to have confidence in them. We don't outlaw them, but we discourage their use unless you are accomplished at reloading with a track record for being successful.

People don't know, and they don't know what they don't know, so that leaves a very big hole. When you are paying me for a class the exact same as the "problem" you want me to troubleshoot, who gets more of my attention? And what is the rest of the class doing when I am fixing your shit ?

We have spare rifles and force people to buy ammo if shit breaks, we can't waste everyone's time sorting out problems of this magnitude when they could have shown up with 200 rounds of factory and been fine.

 

[Long Range 338]

You provided everything needed to answer the question.




He said in the OP that he needed 20Mil to get to 1,400. And provided the range of travel for his optic? Why blast him for not providing all of those details? They aren't actually relevant to the question.

Perhaps you should re-read my post.... There were not any CAPS or maybe please doesn't factor into your vocabulary. I can speculate for days, just as I can do without enough information to verify the drop thru a ballistic calculator. Call it what you wish, redundant, over obsessive, etc. However I wouldn't say that I blasted the OP as tone/demeanor are not well translated into text you seem to have brought your own prebias into the thread. No offense was given nor taken.

ETA: To directly answer your question, the 20 mils mentioned didn't answer how to get them within his scope travel

 

[Rocketvapor]

Not being out to these ranges yet myself I can only speculate that shooting at 1000/supersonic then going to 1400 subsonic would be educational.
Of course being able to dial in, or hold over in the reticle would help.

Why do we get all sensitive and shit when giving advice?
What I do find interesting is where are the target group posters that normally appear?

 

[Steel head]

So, if they allowed reloads you would go to the class?

If the instructor was good he could troubleshoot the reloads for free.
Maybe the class should have SH on quick dial to ask why their reloads wont chamber.

Or a remedial class.
Or send them home if the reloads don't work.

Most of the class will probably be at lesser ranges.
I suggest a 224V, makes it to a mile ( I read somewhere someone did that)
Or maybe it's big brother

Actually I agree 100% with factory ammunition for a class.

I’ve had good success with Hornandy’s 147 6.5CM ammo at just over a mile and you generally don’t have to worry if it will chamber or blow.

thankfully I have access to multiple places to shoot that far and I can use my reloads.

 

[Rocketvapor]

My quote didn't capture your quote.

 

[Long Range 338]

While we are on the subject of loads, OP you might want to look at Lapua's offerings with lighter bullets and run the numbers on them. The velocity gains might be a better fit for what you are trying to do.

 

[Lowlight]

In my CO Classes, we shoot 99% of our students to 1425, and if you have a capable load, including guys with 6.5CMs we let you shoot to a 1 mile during our open shoot.

We are at elevation so most only need about 15 mils to 1425 or less, 12 to 14 work for a lot of guys. At 1 Mile a factory 6.5CM is about 20 Mils for our target

 

[acudaowner]

not sure how correct this is , my math skills suck about as much as my ability to spell anymore , but you said you needed 21 mil of elevation if a mill is 3.6 inches at 100 yards that same 3.6 inches at 1000 yards is 36 inches . You need 21 mills decided by 3.6 = 5.8 inches needed , sight your scope in at 400 yards and raise your bi pod up 4 or 5 clicks if it is like my atlas has 1'' rings or spacers so every click is 1 inch of height . I would I think just need to make up the .8 + or - what you need to impact center ? again sorry my math skills are really bad I know there is a rat somewhere in a lab getting a kick out of my attempts . then you could use your scope or try and see if its correct or how spectacularly wrong i am either way I hope you have a great time in your class .

 

[Lowlight]

If your scope can zero at 100, changing your zero range does nothing in adding in elevation to the overall value. you can still only get what you can get, the only way to add in more elevation is to change the cant under it.

it's only if you cannot reach 100 do you zero at different distances to extend the range out further. but simply zeroing at a new range does nothing to your overall elevation

 

[Rocketvapor]

acuda,
Try your math this way;
length of support radius bag to bipod.
Say 24".
0.1" rise in bipod would be 15 inches at 100yds (3600 inches), 210 inches at 1400 yds
corrected my math errors

Would you still see the target in the scope?

 

[Rocketvapor]

All these folks talking about going to class.
I would love to go to a long range class, even at my age.
Maybe I should start a Go-Fund-Me page

Even my little 22N would be supersonic @ 1400 yds up in Co (not down where I live).
20 moa in the scope, 20 moa in the mount, a couple moa hold over.

 

[want2learn]

thanks everyone, just got back from the store....they had a pair of Burris scope rings that come with two +10 and two -10 plastic inserts....going to try them out shortly....

everyone's been awesome, thank you for the information....

BTW, lowlight....really looking forward to your book.....perhaps one day i'll have the opportunity to take one of your classes and have you autograph it. This truly is a great forum and a wonderful resource. thank you again.

 

[dustingaunder]

I always assume I’m in the middle plus 1.5 mils for a flat base and 100 yard zero.

total travel in mils / 2 - 1.5 is what I have left.
Take that plus the cant in the base.

20MOA = 5.82mils
25MOA = 7.27mils
30MOA = 8.73mils
35MOA = 10.18mils
40MOA = 11.64mils
45MOA = 13.09mils

That’s your total elevation you have left approximately

21 / 2 - 1.5 = 9 mils available for flat base.

40 MOA base to get you all 20 mils but you’ll probably not be able to get a 100 yard zero. 30 MOA base will get you around 17-18 mils of up.

 

[Matches Malone]

This ^

Whoever up there said you get 10 mils from a 20 moa base, your guess sucks.
For future reference the exact math is 20 (moa)/3.438= 5.8 mils.
The scope comes new from the factory with a mechanical zero.
This is why you can assume that you will have about half of the scopes total adjustment. It’s generally unknown exactly where you’re 100y zero will end up but it will usually be around that of a full mil if you’re rifle is typical.

30 moa base, 100y zero, 10 mils in reticle, you’ll have enough to get out to about 1500y with that muzzle velocity. If you can find a higher BC bullet, that might shave a mil or two down as well.

 

[want2learn]

thank you. i don't think anyone else makes commercially available factory ammunition with a higher BC for this caliber.

......but i also reload and so i'll research what i might be able to make for local competitions.

 

[dustingaunder]

Reload.
Put reloads in factory boxes.
Profit.

 

[Lowlight]

If a student asked me,

Hey, I have reloads, and I know how to reload and they work, but also showed up with factory ammo first that would be the best-case scenario. You can shoot the first day with the factory ammo, mix in some reloads to show they are good, and then transition at whatever point

For me and my classes, we go back and forth to 100 a lot because we see scope issues better by doing this, when guys are not returning or because they are improving so the zero walks a bit. I like to double check at 100 throughout the class. During these opportunities, you can mix in reloads to demonstrate they work and to use them to push to the farther distances. We start short, end long, so this works