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NC, USA
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Posted: 5/11/2024 11:30:13 AM EDT
[Last Edit: MFP_4073]
for instance -- using a .308 ACOG on a 5.56mm rifle etc ??
in a perfect world i could have all the ACOGs precisely matched. but at ~$1K + each ... (i'll go be poor elsewhere) between 50 and 300 yards -- do it matter that much ?? ballistics, trajectory, etc |
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Posted: 5/11/2024 11:31:57 AM EDT
[Last Edit: 45-Seventy]
[#1]
In the real world, every BDC is inaccurate.
Know your dope and download a calculator to figure out what range settings match up to your load at what range. If you’re only stretching to 300, it matters even less. |
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USA
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Posted: 5/11/2024 11:52:19 AM EDT
[#2]
Not enough to really notice. Most BDCs are just a reference anyway.
If you really want finagle your zero you can get the reticle subtensions off Trijicon’ as site and chrono your ammo and plug all the info into a ballistic calculator to figure out the best way to zero (however high @ 100 meters or whatever) to best track with the lower BDC marks. I think .308 ACOGs match a 16” 5.56 shooting MK262 pretty well too from when I crunched the numbers years ago. |
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Posted: 5/11/2024 11:54:06 AM EDT
[#3]
You will have slight variations but after a while you'll know very easily where you need to hold for each distance.
As stated, under 400Y on torso sized targets really doesn't matter. It's only beyond that where you will start noticing a deviation. |
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Posted: 5/11/2024 11:59:49 AM EDT
[#4]
100 or so years ago before they came out with a 7.62x39mm BDC model, we used .308 BDC 3x30's on our AKs. The difference seemed to be slight, and 300 yard hits were not an issue.
Once the X39 models came out, we moved the .308 BDC ones to M1As and bought X39 BDC models for the AKs. |
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OH, USA
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Posted: 5/11/2024 12:02:34 PM EDT
[#5]
my memory is fuzzy, but i think there was once a tacked thread in the optics area about this.
basically is was something like: "you have ACOG X, but you're running barrel length of Y and ammo Z, here are what the hold over points will be" anyone else remember this? |
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TX, USA
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Posted: 5/11/2024 12:16:58 PM EDT
[#6]
I have found that if you use a ballistic calculator and simply adjust your zero distance you can get almost anything to line up from 200 to 450-500 meters. Inside 200 doesn’t really matter anyway.
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FL, USA
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Posted: 5/11/2024 12:54:04 PM EDT
[#7]
All the above but you still should/need to shoot it at actual distances to compare to what you expect it to be. Remember too, most ACOGs are calibrated in meters not yards, after 300 makes a difference.
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Posted: 5/11/2024 1:11:33 PM EDT
[#8]
Take a look at a ballistics chart. You'll learn that BDC's are mostly hooey.
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Posted: 5/11/2024 1:18:24 PM EDT
[#9]
Quote HistoryOriginally Posted By AeroE: Take a look at a ballistics chart. You'll learn that BDC's are mostly hooey.  Attached File |
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Posted: 5/11/2024 1:18:34 PM EDT
[#10]
Quote HistoryOriginally Posted By 45-Seventy: In the real world, every BDC is inaccurate. Know your dope and download a calculator to figure out what range settings match up to your load at what range. If you're only stretching to 300, it matters even less. Also, 45-Seventy actually shoots, and knows what they're talking about. |
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Posted: 5/11/2024 1:27:13 PM EDT
[Last Edit: -OdieGreen-]
[#11]
The ACOG’s BDC has probably taken out more people than any other bullet drop compensating reticle ever made. Probably even if you combined them all. I wouldn’t consider it snake oil by any means. Plenty of videos of silhouette hits at 600 using BDC too. That said, it can’t do everything for you and has requirements to be functional.
OP I don’t know your answer with Biden banning Strelok. |
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Posted: 5/11/2024 1:43:50 PM EDT
[#12]
Quote HistoryOriginally Posted By Krej: I have found that if you use a ballistic calculator and simply adjust your zero distance you can get almost anything to line up from 200 to 450-500 meters. Inside 200 doesn’t really matter anyway. Yep |
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Posted: 5/11/2024 1:51:20 PM EDT
[#13]
Quote HistoryOriginally Posted By -OdieGreen-: The ACOG’s BDC has probably taken out more people than any other bullet drop compensating reticle ever made. Probably even if you combined them all. I wouldn’t consider it snake oil by any means. Plenty of videos of silhouette hits at 600 using BDC too. That said, it can’t do everything for you and has requirements to be functional. OP I don’t know your answer with Biden banning Strelok. You can still download Strelok to either iOS or Android. The author has provided steps on his FB group. https://www.facebook.com/groups/StrelokBallisticsUserGroup/posts/2004792326558365/ |
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Posted: 5/11/2024 1:57:16 PM EDT
[#14]
Quote HistoryOriginally Posted By Stainless: "you have ACOG X, but you're running barrel length of Y and ammo Z, here are what the hold over points will be" Except on Tuesdays and alternate Fridays. Stuff like this is calibrated to a certain rifle with a certain ammo and EVERYTHING including barometric pressure are going to change thing to some degree or another. for example, USGI ammo, while junk, certainly isn't match grade. You have to have realistic expectations when using something like a BDC and it often boils down to practical experience. I use the term 'some idea' of what will happen meaning in the ball park. Something like an ACOG is nothing more or less than just another tool to work with. |
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Posted: 5/11/2024 2:06:19 PM EDT
[#15]
Quote HistoryOriginally Posted By out4trout: https://www.ar15.com/media/mediaFiles/42994/hes_right_you_know-328_jpg-3211647.JPG Quote HistoryOriginally Posted By out4trout: Originally Posted By AeroE: Take a look at a ballistics chart. You'll learn that BDC's are mostly hooey. https://www.ar15.com/media/mediaFiles/42994/hes_right_you_know-328_jpg-3211647.JPG Mostly hooey means that inside 400 yards (or 600 with experience) there is no point worrying about whether the reticle is for .308 Win or .223 Rem. Especially since you've used the rifle and reticle and worked out the hold for the ammo and distances, which most will ignore after a while. |
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Posted: 5/11/2024 2:38:10 PM EDT
[Last Edit: FightingHellfish]
[#16]
Every BDC is equally accurate with any load and zero on any weapon. Every reticle is a BDC.
Just don’t expect it to be 200/300/400/500.  Attached FileJust need to remember those numbers. |
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Posted: 5/11/2024 2:42:56 PM EDT
[#17]
What I would do is take a picture of the moon through the ACOG. The moon is anywhere between 29 and 33 arcminutes (aka minute of angle). Open it up in paint, and measure how many pixels the moon is. If the moon is 100 pixels in diameter, then 1 pixel = 30/100= 0.3moa for example. Now you can figure out exactly what MOA of drop the holdover lines correspond to by measuring the reticle on the same picture
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USA
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Posted: 5/11/2024 2:52:52 PM EDT
[#18]
The bdc's will be off based on what bullet you are using and muzzle velocity. You can use a ballistic calculator and change your zero distance to make them match up close enough.
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Posted: 5/11/2024 2:53:44 PM EDT
[#19]
Quote HistoryOriginally Posted By FightingHellfish: Every BDC is equally accurate with any load and zero on any weapon. Every reticle is a BDC. Just don’t expect it to be 200/300/400/500. https://www.ar15.com/media/mediaFiles/64501/IMG_0681_png-3211714.JPG Just need to remember those numbers. One of my college professors once said “all models are incorrect, some are useful”. All (multipoint) reticles are BDC reticles, to an extent, if you take the time to learn how to use them. |
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Posted: 5/11/2024 2:59:06 PM EDT
[#20]
Quote HistoryOriginally Posted By 56xdx_Z: What I would do is take a picture of the moon through the ACOG. The moon is anywhere between 29 and 33 arcminutes (aka minute of angle). Open it up in paint, and measure how many pixels the moon is. If the moon is 100 pixels in diameter, then 1 pixel = 30/100= 0.3moa for example. Now you can figure out exactly what MOA of drop the holdover lines correspond to by measuring the reticle on the same picture You really do that? |
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TX, USA
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Posted: 5/11/2024 3:02:50 PM EDT
[Last Edit: mcantu]
[#21]
Quote HistoryOriginally Posted By 56xdx_Z: What I would do is take a picture of the moon through the ACOG. The moon is anywhere between 29 and 33 arcminutes (aka minute of angle). Open it up in paint, and measure how many pixels the moon is. If the moon is 100 pixels in diameter, then 1 pixel = 30/100= 0.3moa for example. Now you can figure out exactly what MOA of drop the holdover lines correspond to by measuring the reticle on the same picture Or...you could look on the Trijicon web site and find the reticle moa measurements there  |
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Posted: 5/11/2024 3:07:55 PM EDT
[#22]
Quote HistoryOriginally Posted By mcantu: Or...you could look on the Trijicon web site and find the reticle moa measurements there I just went next door and explained to the neighbor lady that I need to take a picture of Uranus through my ACOG to calculate my BDC on Microsoft Paint. Now I just got served with a restraining order and divorce papers. I wish I’d just tried Google first. |
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Posted: 5/11/2024 3:09:37 PM EDT
[#23]
Quote HistoryOriginally Posted By FightingHellfish: You really do that? One time, to figure out the exact measurements of an EXPS3-2 reticle. I used a couple stars and not the moon though. Second dot is 9.6moa below the center dot. Ring is 65 and not 68 MOA confirmed. Hash marks extend 8.5moa from the ring and are 2moa thick. If trijicon actually publishes moa measurements of these, then this whole thing could have been answered with a ballistic calculator |
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Posted: 5/11/2024 3:11:46 PM EDT
[#24]
Ta01nsn is close enough on a 16” ar10.
Learn where it hits and learn your holds. |
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OH, USA
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Posted: 5/11/2024 3:13:57 PM EDT
[#25]
Quote HistoryOriginally Posted By piccolo: Except on Tuesdays and alternate Fridays. Stuff like this is calibrated to a certain rifle with a certain ammo and EVERYTHING including barometric pressure are going to change thing to some degree or another. for example, USGI ammo, while junk, certainly isn't match grade. You have to have realistic expectations when using something like a BDC and it often boils down to practical experience. I use the term 'some idea' of what will happen meaning in the ball park. Something like an ACOG is nothing more or less than just another tool to work with. Quote HistoryOriginally Posted By piccolo: Originally Posted By Stainless: "you have ACOG X, but you're running barrel length of Y and ammo Z, here are what the hold over points will be" Except on Tuesdays and alternate Fridays. Stuff like this is calibrated to a certain rifle with a certain ammo and EVERYTHING including barometric pressure are going to change thing to some degree or another. for example, USGI ammo, while junk, certainly isn't match grade. You have to have realistic expectations when using something like a BDC and it often boils down to practical experience. I use the term 'some idea' of what will happen meaning in the ball park. Something like an ACOG is nothing more or less than just another tool to work with. i found the old thread. hopefully this is what OP was looking for. if not, that's cool too. https://www.ar15.com/forums/ar-15/-/18-229420/? |
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Posted: 5/11/2024 3:13:59 PM EDT
[Last Edit: FightingHellfish]
[#26]
Quote HistoryOriginally Posted By 56xdx_Z: One time, to figure out the exact measurements of an EXPS3-2 reticle. I used a couple stars and not the moon though. Second dot is 9.6moa below the center dot. Ring is 65 and not 68 MOA confirmed. Hash marks extend 8.5moa from the ring and are 2moa thick. If trijicon actually publishes moa measurements of these, then this whole thing could have been answered with a ballistic calculator Wouldn’t known size reference marks on a target at a precise known distance be easier and more precise? Assuming you couldn’t find, or didn’t trust, online reticle diagrams. Related question: on some, or all, scope designs, can turning the objective focus make small changes to the perceived size of the reticle? |
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Posted: 5/11/2024 3:25:41 PM EDT
[Last Edit: 56xdx_Z]
[#27]
Quote HistoryOriginally Posted By FightingHellfish: Wouldn’t known size reference marks on a target at a precise known distance be easier and more precise? Assuming you couldn’t find, or didn’t trust, online reticle diagrams. Related question: on some, or all, scope designs, can turning the objective focus make small changes to the perceived size of the reticle? Not sure about more precise, but it is certainly possible to do the same thing by photographing the reticle against a target with a 1 inch grid at a measured distance, like at a 100yd range. You probably would not like my method for collimating dual PVS14s. Those things can only move in one circular axis of motion, so one way is to put each pvs14 between a mil-dot scope and a red dot, and plot the intersection of the red dot against the mil dot reticle, then the problem becomes finding the intersection(s) of two circles and simply spinning each pvs14 eyepiece to put the dot in that spot. Neighbor lady might be sending more than divorce papers on that one lol ETA: No idea if focus changes impact the size of the reticle |
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USA
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Posted: 5/11/2024 3:49:00 PM EDT
[#28]
I wouldn't worry about it. Most people shooting 55gr are using the incorrect 223/556 reticule instead of the m193 reticule. If they take a peek at the bottom of reticule it's not going to say m193 and their drops are all off.
This is the right one if you aren't shooting 62 grain m855. https://www.trijicon.com/products/details/ta31-d-100288 |
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Posted: 5/11/2024 4:03:09 PM EDT
[#29]
Outside of some of the weird reticles any of them can work well. I've never played with the apps but even just messing around them you can get them very close.
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NC, USA
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Posted: 5/11/2024 4:46:08 PM EDT
[#30]
good info Gents -- thanks
one issue is product availability -- various models are BO oftentimes right now EuroOptic has a.223 Red Chevron TA33 for like $950 very tempted |
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