Drop versus holdover
- Thread starter tpcollins
- Start date
I’m only concerned about holdover - or with a BDC reticle - at 50 yards with a 30 yard zero. Thanks.
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5" or 5 feet, you measure it the same way, by eye and you guess. Or if you're more precise, you "estimate".
First off, you need to know the range, with reasonable accuracy. Being off by even 50yards (or sometimes even 25yds) can make a significant difference in the drop, depending on the bullet's velocity at that range.
and you need to know the drop characteristics of what you are shooting. Huge difference between a .45-70 and a .300 Mag.
OK, so you know the range, and you know the drop (and we'll leave wind drift out of this for the moment) then is it a "simple" matter of adjusting your point of aim to compensate.
Lets take your 5" drop, as the example. One way is to crank in 5" more elevation on your scope (or iron sight if it will do that) and then aim dead on target.
The other way is to aim those 5" above where you want the bullet to hit. I include holdover (or under) in the term "Kentucky windage" but some do not.
Point here is that holdover is almost never as precise as adjusting the scope, but it is FASTER, and your sights remain zeroed where you set them. You don't have to crank them up for the shot then REMEMBER to crank them back down to the original setting.
They way its most often done is to use the size of a known object for reference. This includes the game you are shooting at. IF you know, for example that, broadside, the deer is 12" (roughly) back to belly, and you need to hold 5" high, then you hold just a touch less than "half a deer high" and your bullet should land in the boiler room.
ANY object at that distance that you know the size of can be your reference. For example, if you know that the fence post the deer is next to is 5 feet high, you can estimate fairly well down to half a foot or so.
Of course, this takes practice and different people will be differently skilled doing it, but its easily done, and has been done since people started launching things at game, or each other. Archers are skilled at estimating range and drop of their arrows the same way. The ones who aren't are considered poor archers.
And, speaking of which, a friend of mine who was a bowhunter spent all summer practicing in his backyard for the "40 yards shot", determined to get his deer. That fall, the deer jumped up 25yds from him, and he did what he's spent all summer practicing. And shot right over the deer's back...
The same principles apply to any and every ranged weapon. (in earth's gravity well, at any rate...
)Assuming there is sufficient adjustment in your scope or sights, adjusting the sight for drop is fairly simple and quick, and usually more precise than estimating the hold over.
BUT
There is an important thing that must be done, and often is forgotten. And that is putting the sight / scope BACK to its original zero setting after making the shot. Particularly when hunting! Its an easy thing to forget, after you've 've made your shot, but if you don't reset your scope to where it was zeroed, the NEXT time you shoot, (at a different distance) or adjust it for drop you're going to be WAAY off.
If its your habit to adjust the your scope to compensate for drop on the shot, then ALSO make it your habit to return the scope setting to where it was before you adjusted it. Do not pass GO, do not collect $200, do not do anything else not vital before resetting the scope. Otherwise, your next shot is very likely to be a miss.
And, if you're like some of us, and say. "well, I'll do it later" often later, we forget to do it. or think we did it, when we didn't. Either way, next shot at any different range is going to be a miss.
Some folks make a "witness mark" on the sight.scope for the "zero" setting. THis allows you to see, at a glance if your sight is set where you expect it to be.
Personally I rarely adjust the sights I "guesstimate" the hold over, and so my sights remanin of their zero, which is a useful thing, for me.
BUT
There is an important thing that must be done, and often is forgotten. And that is putting the sight / scope BACK to its original zero setting after making the shot. Particularly when hunting! Its an easy thing to forget, after you've 've made your shot, but if you don't reset your scope to where it was zeroed, the NEXT time you shoot, (at a different distance) or adjust it for drop you're going to be WAAY off.
If its your habit to adjust the your scope to compensate for drop on the shot, then ALSO make it your habit to return the scope setting to where it was before you adjusted it. Do not pass GO, do not collect $200, do not do anything else not vital before resetting the scope. Otherwise, your next shot is very likely to be a miss.
And, if you're like some of us, and say. "well, I'll do it later" often later, we forget to do it. or think we did it, when we didn't. Either way, next shot at any different range is going to be a miss.
Some folks make a "witness mark" on the sight.scope for the "zero" setting. THis allows you to see, at a glance if your sight is set where you expect it to be.
Personally I rarely adjust the sights I "guesstimate" the hold over, and so my sights remanin of their zero, which is a useful thing, for me.
This is also where first focal plane reticles come into play. With a second focal plane reticle the reticle changes size when you change the power of the scope (which is why for the longest time you saw fixed 10X scopes on issued sniper rifles/DMRs). With a first focal plane scope 5" on the reticle is always 5" no matter what power you have the scope set to.
If you've just got a Duplex reticle you're going to have to get good at figuring out the size of the target in the reticle based on what distance you are shooting, and from there you can estimate the 5" holdover.
If you've just got a Duplex reticle you're going to have to get good at figuring out the size of the target in the reticle based on what distance you are shooting, and from there you can estimate the 5" holdover.
Let's not over complicate this. Five inches of drop is no biggie. Virtually all common hunting rifle cartridges zeroed at 100 yards will be 2-3" low at 200, maybe 5" low at 250 and around 10" low at 300 yards. It is only well beyond 300 yards where drop and accurate range estimation becomes critical.
You also have to consider that a typical deer has a 10-12" kill zone. An animal like elk is 18-24". If you're deer hunting and estimate a deer is less than 200 yards away just hold where you want to hit. You'll be within 2-3" with a 10-12" bullseye.
If you estimate somewhere between 200, but no more than 300 yards leave a little daylight between the horizontal crosshair and the animals back. Even if your estimation is off by 50 yards any animal between 250-350 yards is going to be hit in vitals.
It is only when you get close to 400 yard shots that you really need to worry. At that distance accurate range estimation via a range finder is critical. Along with a scope that can compensate for drop.
Second focal plane scopes aren't a handicap for hunters. Zero the scope on max magnification which is 7-10X on most hunting scopes. Just keep the scope on the lowest magnification for close shots and use the max magnification, (the one you used to zero) for longish shots. Simply ignore anything in between and this is never a problem.
Where first focal plane comes into play is with target scopes with 20X or more on the upper end. You'll often run into an issue where the max magnification is too much, and the lowest isn't enough. It is only when using those in between that there is a problem.
You also have to consider that a typical deer has a 10-12" kill zone. An animal like elk is 18-24". If you're deer hunting and estimate a deer is less than 200 yards away just hold where you want to hit. You'll be within 2-3" with a 10-12" bullseye.
If you estimate somewhere between 200, but no more than 300 yards leave a little daylight between the horizontal crosshair and the animals back. Even if your estimation is off by 50 yards any animal between 250-350 yards is going to be hit in vitals.
It is only when you get close to 400 yard shots that you really need to worry. At that distance accurate range estimation via a range finder is critical. Along with a scope that can compensate for drop.
Second focal plane scopes aren't a handicap for hunters. Zero the scope on max magnification which is 7-10X on most hunting scopes. Just keep the scope on the lowest magnification for close shots and use the max magnification, (the one you used to zero) for longish shots. Simply ignore anything in between and this is never a problem.
Where first focal plane comes into play is with target scopes with 20X or more on the upper end. You'll often run into an issue where the max magnification is too much, and the lowest isn't enough. It is only when using those in between that there is a problem.
Most of us aren't well versed in mils, which are not the same as inches.
The mil-dot reticle does provide additional aiming points, but unless you are using exactly the cartridge and load they are calibrated to, you'll have to do some range testing to find out exactly where your rifle hits when using them as aiming points.
If it is close, no need to hold. Beyond that, to hold or to adjust.
Can't practically adjust the scope's elevation on the fly, unless you have "tactical turrets". It kinda narrows down.
For a lot of scopes the only practical solution is to hold. How to hold is then the question. There are more than one way. Better way is use reticle "features" to help estimate. You can do a lot of things even with duplex reticle posts and magnification settings.
-TL
Sent from my SM-N960U using Tapatalk
Can't practically adjust the scope's elevation on the fly, unless you have "tactical turrets". It kinda narrows down.
For a lot of scopes the only practical solution is to hold. How to hold is then the question. There are more than one way. Better way is use reticle "features" to help estimate. You can do a lot of things even with duplex reticle posts and magnification settings.
-TL
Sent from my SM-N960U using Tapatalk
Actually it’s why Mil/Mil scopes exist.
A Mil is always a Mil, and with a Mil/Mil optic no extra seconds are spent figuring the MOA —>MIL “conversion” in your head, ... which for your average deer-camp Fuddly just gives him a bad migraine. Meanwhile, the critter in his reticle gets bored waiting to be shot and scoots away.
Noop. Mil/Mil is the way to roll, just like the Navy Seal snipers do, and “range-ess” (range estimation) is something you only get good at by practicing it.
With a confirmed, basic 100-yd zero, you then vet your rifle at other incremental distances (200yds, 300yds, 400yds, etc) by figuring the Mils to the target at those distances, using the hashes on the reticle below the center cross-hair. Then you know what hold-over hash in the reticle corresponds to getting a hit on the target at a given distance. Yes, you might actually have to shoot more than a few rounds to vet all this.
Once done however, and you’re out in the field, if a shootable critter suddenly appears beyond 100yds, you just put the hold-over hash on it that corresponds to that distance, and send a round into its vitals. (Again, why having solid range-ess skill is critical). This also assumes no shooter-induced error, also known as “fuglying the shot.”
Now if the context is your average deer-camp Fuddly up in a Midwest tree stand, where 99.9% of his shots will be inside 75yds, none of this high-speed, Mil/Mil, Navy Seal sniper stuff matters.
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There's 3 or 4 standards for the miliradian.
http://wndsn.com/?d=metrology/MIL_vs_MRAD_vs_NATO-MIL.txt
Which one is used in the USA shooting Sports?
http://wndsn.com/?d=metrology/MIL_vs_MRAD_vs_NATO-MIL.txt
Which one is used in the USA shooting Sports?
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I disagree.