Help with MOA and bullet drop

[Wrench]

Be sure you do not confuse TMOA with SMOA if using a calculator. You'll be trying to back validate your dope and go crazy......also good to think about on tall target tests.

 

[BBob]

Not to mention even when you dial in MOA your scope only adjusts in .250 increments anyway so most of the time you dialing in a small degree of error

Well mby not exactly. There are scopes that are inches per 100 yds (IPHY) and there are those (most of them) that actually do it in true MOA. Small difference yes but at distance it will add up. Ballistic apps will give you the choice between MOA and IPHY. Swarovski is an IPHY manufacturer. Also note there have been MIL scopes that don't conform to what we consider std MIL's (NATO mil). March used true mil's (instead of the more std NATO mil) when they first came along and you have to use an offset value (~.98) to get them to produce a correct drop chart for those scopes. Current March's are NATO mil.

 

[bmart2622]

At 1000yds there is less than a 1/2" difference!!! I wouldn't call that very significant. My BR4 rangefinder gives me my solution in MOA, my scope dials in .25 MOA increments just like most scopes that use yds dial in .25 increments. So if my solution requires 4.35 MOA adjustment you have to dial up or down .15 moa, take your pick.

 

[BBob]

Okay, okay! My manubun is 1.2 moa diff (IPHY vs MOA) at 1K

BTW in terms of drop that's kinda big at 1K and I'd probably miss for sure

 

[np307]

The point thinking in MOA and not inches isn't that there's a .047" difference between the two, its that you're needlessly converting measurements. There's no need to know how many inches something drops.

Going yardage->drop chart->dial->shoot makes way more sense than going yardage->drop chart->convert to MOA->dial-> shoot. It's a needless step that causes confusion like OP is experiencing.

 

[bmart2622]

Thats why most people dont convert it, they just think in terms of 1moa=1" per 100yds, theres still no math or conversions involved

 

[np307]

Thats why most people dont convert it, they just think in terms of 1moa=1" per 100yds, theres still no math or conversions involved

Your conversion value changes with yardage. MOA doesn't. So if you're thinking of drop as 7 inches at 400 yards, you have to first convert your adjustment from 1 inch at 100 to 4 inches at 400 and then dial 7 clicks. If you're thinking of drop as 1.75 moa at 400 yards, you just have to dial 7 clicks.

 

[Msengineered]

It is good to get a ballistics app on your phone, like Hornaday or similar.

Here are some steps I used to dial in my factory ammo to a pretty good level
1.) Get an excellent zero on your scope at 100 yards.
2.) Look at your box of ammo and what the muzzle velocity is. Mine said 2,960 FPS so that is what I entered in my ballistics calculator.
3.) Find a range where you can take a 500 yard shot at a bid piece of steel.
4.) Spray a fresh can of spray paint on your steel target so you can see your impact. I made a big neon green background with about a 5" blaze orange center.
5.) Look at your ballistics calculator for a 500 yard shot, mine said 7.56 MOA, round to your nearest increment, most decent scopes are 0.25 MOA increments.
6.) Aim at the center of the steel and shoot, note where your impact is. If you hit high, your actual bullet speed is faster than the box speed. If you hit low, your actual speed is slower.
7.) My impacts were about 6" low so my bullet was traveling slower than what the box said. At 500 yards, this was just more than 1 MOA off ( 1 MOA is roughly 1 inch at 100 yards so doing the math, 6"/5 = 1.2 MOA).
8.) Add (or subtract) the MOA from step 7 and apply to step 5. I had to add 1.2 MOA so I was at 8.76 MOA.
9.) Play with the speed on your ballistics calculator until you get the speed that will show 8.76 MOA at 500 yards.

This should give you a really good idea of the speed of your factory ammo without buying a chornograph.

 

[eric1115]

At 1000yds there is less than a 1/2" difference!!! I wouldn't call that very significant. My BR4 rangefinder gives me my solution in MOA, my scope dials in .25 MOA increments just like most scopes that use yds dial in .25 increments. So if my solution requires 4.35 MOA adjustment you have to dial up or down .15 moa, take your pick.

No, you have a major gap in your understanding of this. At 1000 yards there is a .47" difference per minute. My .308 needs 28ish MOA correction at a grand, so that's over 13" of error. That is definitely significant.

 

[bmart2622]

1 moa is 1.047", 10 moa =10.47". So if you compare 1" at 100 yds to 1 moa, 10 moa would equal 10.47 " at a 1000yds

 

[hereinaz]

It is helpful to understand the conversion inches/MOA. Good on you for asking the question. I would probably say that you get confused trying to read stuff on Google. Be careful with guys giving you advice about inches/MOA, cause there is outright bad information and confusing information.

It is far more valuable to learn how to use MOA for what it is, an angular measurement. You don't need to make conversions at all or think in inches. Besides, try doing the conversions with inches in your head if it is 437 or 583 yards. It is faster and more effective to use the reticle to measure the angular change needed to be made (if your reticle has hash marks.)

The is a reason that "it is easier" to think inches and MOA, and IMO it is because it takes some time to learn it. So, many it seems never learn how to shoot long range with MOA as an angular measurement. Those who switch to MIL do typically learn to shoot with it as an angular measurement.

If you remember protractors used to measure angles, the scope/rifle is the place where you would put the point of the angle on the protractor, and the target would be the place on the curve that you would use to measure the degrees (except for MOA it is "minute" of angle which are 1/60 of a degree.)

 

[Encore4me]

Are these ballistic apps really that accurate? I know I would have to practice and double check everything but it sounds too easy.
The reason I’m doing all of this is my son and I are going Caribou hunting in 2025 in the Northern Brooks Range Alaska. I have read that some of the shots are up to 500 yds away. I know that is not a lot for you all but it is to me. We both got Tikka 300 WM (not necessarily needed but we are going to do more hunts in the future) and I just laid away a Nightforce NX8 2.5-20x50f1. I could have got a cheaper scope but I wanted something very durable. If I have a nice scope I might as well learn how to use it.


Sent from my iPad using Tapatalk

 

[bmart2622]

Yes they are accurate and yes you need to validate them

 

[eric1115]

1 moa is 1.047", 10 moa =10.47". So if you compare 1" at 100 yds to 1 moa, 10 moa would equal 10.47 " at a 1000yds

No, not even a little bit.

1 MOA is 1.047" at 100 yards.
1 MOA is 10.47" at 1000 yards
10 MOA is 104.7" at 1000 yards.
28 MOA (my correction on my .308 at 1000 yards) is 10.47x28=293.16". If you round off that .047 and just do 1" per 100, you get 280" and miss by over 13".

 

[bmart2622]

My bad, I fat fingered that. I meant 1 moa at 100 yds =1", 1 moa at 1000yds =10.47". Strictly comparing 1" to 1MOA

 

[bmart2622]

If you are looking at a buck at 500 yds and his rack width spans 5moa in your scope, how wide is the buck? Hoow about a buck at 1000yds that spans 3 moa, how wide is he?

 

[eric1115]

If you are looking at a buck at 500 yds and his rack width spans 5moa in your scope, how wide is the buck? Hoow about a buck at 1000yds that spans 3 moa, how wide is he?

Sure, in that context, I will definitely drop the 0.047. That's not the context that the question was being asked in though. The context was regarding dialing corrections at distance, where it absolutely does matter.

 

[bmart2622]

Actually if you go back to the beginning of the thread the very first question was if 1 " =1moa at 100yds and thats what the discussion was about and what I am/was commenting on

 

[Msengineered]

Are these ballistic apps really that accurate? I know I would have to practice and double check everything but it sounds too easy.
The reason I’m doing all of this is my son and I are going Caribou hunting in 2025 in the Northern Brooks Range Alaska. I have read that some of the shots are up to 500 yds away. I know that is not a lot for you all but it is to me. We both got Tikka 300 WM (not necessarily needed but we are going to do more hunts in the future) and I just laid away a Nightforce NX8 2.5-20x50f1. I could have got a cheaper scope but I wanted something very durable. If I have a nice scope I might as well learn how to use it.


Sent from my iPad using Tapatalk

The balistics apps I have seem to be very good for bullet drop. The jury is still out on windage corrections due to a cross breeze.

 

[wind gypsy]

Are these ballistic apps really that accurate? I know I would have to practice and double check everything but it sounds too easy.
The reason I’m doing all of this is my son and I are going Caribou hunting in 2025 in the Northern Brooks Range Alaska. I have read that some of the shots are up to 500 yds away. I know that is not a lot for you all but it is to me. We both got Tikka 300 WM (not necessarily needed but we are going to do more hunts in the future) and I just laid away a Nightforce NX8 2.5-20x50f1. I could have got a cheaper scope but I wanted something very durable. If I have a nice scope I might as well learn how to use it.

Yes, they are accurate if you understand the inputs that can effect their accuracy. Many people in a situation like you describe look at them as a short cut that allows them to maintain ignorance on ballistics because the calc does the work for them then they don't know what happened when their solution is wrong.

500 yards is getting pretty far in field conditions for most everyone despite what they tell you on the internet. Especially on flatter ground where you're prone to get a bad range reading.

300 wm tikkas are not going to be much fun to learn with. They pack a wallop.

Sorry for the negativity...