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I have the TA33R8 on a CMMG 14.5 1/7 hvy, flat top upper with PWS gas piston.
The scope is on a ARMS #19LD and #38 swan sleeve. How does this equate for proper zero using the BDC? |
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Great thread! I'd love to have similar information for the new 6x48 ACOGs.
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Best Thread Ever
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Any information on the TA33 with various barrel lengths and various types of ammo?
edit: or would it be similar to the other 62gr. 5.56mm Flattop BDC's? |
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Sorry for this question because it was probably already addressed but I don't want to sight my optic in wrong. A standard TA01 on a flat top using M193 should be sighted in according to the manual? Thanks.
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I'll be receiving an ACOG TA33-R8.
It's going to be on an Armalite M15A4 11.5" 5.56 1/9 twist and loaded with SS109 ammo. What kind of BDC will I get ? What kind of sigh-in should I do ? |
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The MV of a 2970 FPS for a 62 grain bullet from a 14.5" barrel has all ways bugged me. May be from a 20" barrel. When I contacted Trijicon about the BDC for my TA31DOC, I was told it is for a 62 gr bullet traveling @ 2800 FPS. The rep said it is the same for the TA01NSN etc. This sounded more reasonable to me, but wanted more proof. Just looking through some load manuals I have laying around, MVs for 62/63 grain bullets with a 24" barrel at best were 3200 FPS. Loosing 10" of barrel will equate to more than 200 fps loss of MV.
Just a thought..... |
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Funniest screen name ever...........Howie_Feltersnatch
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tag
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I'm guessing that since the TA31H is flattop designed mount, that it uses the 62 grain m855 BDC? Anyone able to confirm?
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Anyone know how much of a difference using SAMMI spec loading with the same bullet will effect the calculations with NATO ammo (i.e. using 55 grain .223 instead of M193)?
I realize that the slower velocity would cause the bullet to drop faster, but is it enough of a difference to notice? |
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"It seems that even Allah's promise of paradise loses a bit of it's luster when there's a dude reigning death on your buddies from 600 meters out." - John_Wayne777 on Battle for Al Najaf 04/04/04
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For those of you who want a 75gr load for your M4 to match the BDC of the TA01NSN (based off of M855): http://www.ar15.com/forums/topic.html?b=6&f=42&t=278324&page=1
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"How many times do I have to tell you, John? I always have a plan..." - Benjamin Linus
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Does anyone know if the BDC on the TA31RCO-M4 is the same as the TA31F? I'm looking for the closest match I can find for a flattop 16" shooting 75-77 gr...
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Originally Posted By hossb7:
Any information on the TA33 with various barrel lengths and various types of ammo? edit: or would it be similar to the other 62gr. 5.56mm Flattop BDC's? No answer in a year and a half. I think that would be the one to use. Lumpy, can you put the TA33 into it's correct spot? |
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Remind me
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Okay, here's what I came up with for the TA-33 with the horseshoe reticle for my 16" flat-top, with Prvi 75gr OTM based on 2525fps & .351 BC. I ran the numbers through the JBM ballistics calculator to get the dope.
@ 100 Yards, top of center dot for zero @ 200 Yards, bottom of center dot @ 275 Yards, top of illuminated post (300 yard marker) @ 375 Yards, top stadia line (Marked 4) 3" low @ 450 Yards, middle stadia line @ 550 Yards, bottom stadia line, 6" low. |
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Any one interested in helping me put together a 4x32 ACOG chart? All the different models have me confused. (there are TA01s for 20 inch 193 and then other TA01s for 14.5 855, there are a bunch of different TA31s, etc) The FAQ on the Trijicon site only addresses a few models. My goal is to get everything into an excel file and post for all to reference.
Model.........................Calibration Barrel Length..........Flat Top (FT) or Carry Handle (CT)..........Calibration Bullet TA01 TA01B TA01ECOS TA01LAW TA01NSN TA01NSN-RMR TA31 TA31-CH TA31-G TA31A TA31ECOS TA31ECOS-G TA31F TA31F-A TA31F-G TA31F-RMR TA31H TA31H-68 TA31H-68-A TA31H-A TA31H-G TA31RCO-A4CP TA31RCO-M150CP TA31RCO-M150CP-G TA31RCO-M4CP TA31RMR TA31RMR-A TA31RMR-G |
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Ok, lemme make sure I got this. I get the BDC data from trijicon for a ta11h. Plug that info into JBM and set zerofor 100 meters, and have the trajectory dump in meters, and the resulting ballistic data should be the starting point for matching my load. Then, use JBM to create tables to get the trajectory as close as I can to the scope's BDC data, correct? Trying to get the 300 & 400 marks as close to the default as possible.
FYI, trijicon gave me a MV of 3,050 for the ta11-h, which is different than the 2,970 that's in this thread. |
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My points of impact are a good bit different than those projected from the chart. From my 16 inch flat top, ACOG TAO1NSN shooting Privi 55 grain M193, when zeroed at 100 YARDS I get the following:
200 yards: Right on with 200 line. 300 yards: 5 inches higher than the 300 line. 500 yards: 10 inches higher than the 500 line. It is consistant so I don't mind aiming low for longer ranges. Have not tried 600 yards yet. |
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Untacking this thread and
marking it as "Do not archive". It's also been added to the "Important Links/FAQ" tacked at the top of the forum. |
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Daddy loves you. Now go away.
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Originally Posted By itgoesboom: Okay, here's what I came up with for the TA-33 with the horseshoe reticle for my 16" flat-top, with Prvi 75gr OTM based on 2525fps & .351 BC. I ran the numbers through the JBM ballistics calculator to get the dope. @ 100 Yards, top of center dot for zero @ 200 Yards, bottom of center dot @ 275 Yards, top of illuminated post (300 yard marker) @ 375 Yards, top stadia line (Marked 4) 3" low @ 450 Yards, middle stadia line @ 550 Yards, bottom stadia line, 6" low. The manual that came with my TA33G-H shows only chevron aiming points. (Same with the online version...) Without getting too crazy about match accuracy, would it be fair to assume that the above data will hold reasonably true for Hornady TAP 60-gr. from a 16" flattop? I'd like to set the top of the center dot at a 6 o'clock hold on a 100 meter zero, the bottom of the center dot at 12:00 hold for 200 meters, and hope the other range markings are close. |
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Social de-evolution appears complete. Typical human behavior is now entirely absent.
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Originally Posted By eracer:
Originally Posted By itgoesboom:
Okay, here's what I came up with for the TA-33 with the horseshoe reticle for my 16" flat-top, with Prvi 75gr OTM based on 2525fps & .351 BC. I ran the numbers through the JBM ballistics calculator to get the dope. @ 100 Yards, top of center dot for zero @ 200 Yards, bottom of center dot @ 275 Yards, top of illuminated post (300 yard marker) @ 375 Yards, top stadia line (Marked 4) 3" low @ 450 Yards, middle stadia line @ 550 Yards, bottom stadia line, 6" low. The manual that came with my TA33G-H shows only chevron aiming points. (Same with the online version...) Without getting too crazy about match accuracy, would it be fair to assume that the above data will hold reasonably true for Hornady TAP 60-gr. from a 16" flattop? I'd like to set the top of the center dot at a 6 o'clock hold on a 100 meter zero, the bottom of the center dot at 12:00 hold for 200 meters, and hope the other range markings are close. Curious as well. But I shoot 50 grain hollow points out of a 16" 1:7 WOA stainless barrel. |
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Friendship is like peeing on yourself: everyone can see it, but only you get the warm feeling that it brings.
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I need to know what TA31-rcoA4 will be on a 20" barrel flat-top using 55gr xm193 will be with the BDC.......
I'm trying to make an A4gery but can't afford to shoot expensive M855 every time I go out shooting. Help me out guys. |
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Originally Posted By Scooter1942:
I've been trying to figure out BDC's too. I just received this from Trijicon this morning. While it doesn't address the flat top/carry handle issue, it does reveal muzzle velocities (based on barrel length) for most of their models. http://i24.photobucket.com/albums/c35/scooter1942/TrijiconReticles.jpg ETA: the TA31TRD, not listed in the chart is based on a 14.5" barrel length. Thanks for posting this. I have a TA11E on a .308 16" flat-top. I had been basing my BDC zero on a 20" barrel (adjusted to my 16") and now need to do some ballistic kung-fu to figure out the zero based on a 22". |
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Originally Posted By Bartholomew_Roberts:
Originally Posted By swenis:
I have a TA11F that's going on my Noveske Afghan upper. How would I zero it to best accommodate Black Hills 75gr. ammo (blue box)? Not enough information to tell. You need to know height over bore (2.5" for a TA11 in a TA51 mount), ballistic coefficient of the 75gr Hornady, and muzzle velocity from the Afghan barrel. Also, I don't have the time anymore to figure out that data for everyone who wants a specific match for their rifle; but I can tell you how to do it yourself. When you have all those things take a ballistics computer and enter the info from "Stats used to figure BDC baseline" for the ACOG of your choice (For the TA11F, it would be M855 traveling at 2,970fps with a BC of .304 and a height over bore of 2.5"). Assume a zero of 100yds. Note the rise/drop every 100yds or 100m. You can do more if you like; but all you are doing is describing points on a parabola for comparison. Now enter the data from your Novseke Afghan into the ballistics computer. Adjust the zero range on the ballistics calculator until the trajectory best matches the data you have written down for every 100m. You are unlikely to get a perfect match and you may have to decide whether you need a greater match close-in, or a greater match at distance. When you have a zero distance that gives you a trajectory you can live with, note the rise or drop at the range you will physically zero the ACOG (for example say 1.2" high at 100yds). When you go to the range, adjust your ACOG until you are striking 1.2" over the point of aim (which should be the outside tip of the chevron for the TA11F). Here is a handy online ballistics calculator if you don't already have a program: www.norma.cc/htm_files/javapagee.htm So if I understand it right then based on the TA11F whose BDC was calculated with a 2.5" over bore height, 62gr M855 @2970 FPs and .304BC and plug that into a 16" AR using that optic and a 75gr Hornady HPBT with a .395BC @2615fps and 2.5" over bore height then it works out that @100m zero the rifle 1.2" high then impacts will be: @200m it will be 1.1" high @300m it will be 0.4" low @400m it will be 3" low @500m it will be 6.1" low @ 600m it will be 8.8" low? Is that how you calculate it? I just wanna be sure cause I am deciding on a ACOG to buy and though a TA11C would fit best I hate that reticle so I am looking at other options. |
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tag for later .
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Lost in PA ....
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Originally Posted By Scooter1942:
I've been trying to figure out BDC's too. I just received this from Trijicon this morning. While it doesn't address the flat top/carry handle issue, it does reveal muzzle velocities (based on barrel length) for most of their models. http://i24.photobucket.com/albums/c35/scooter1942/TrijiconReticles.jpg ETA: the TA31TRD, not listed in the chart is based on a 14.5" barrel length. in this image trijcon has the TA11F with a 20" barrel, but in post #2 it says the TA11F was calibrated using a 14.5" barrel (and M855 + Flattop mount). In post #4 it says 20" barrels were carry handle calibrated. So is this 14.5" flat and 855, or 20" carry and 193? It's confusing, I wish they would just post exactly how each model was calibrated. |
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Bringing back an old thread, but it's really the only place to put it....
I checked my M855 speeds today, and I got an avg of 2990 out of 16 inch barrel. I believe 14.5 is 2900... now I *think* they used 2970 to set the BDC on the TA01NSN, so I should be ok I guess. the FAQ says the diff is minimal, but 100fps is a big diff I think, no? |
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Given TA11C is the best for heavy 77 gr SMK, etc. on a 16" 1/8 flattop, how badly would M855 deviate if sighted in for 77gr?
I never had much luck with M855 at longer ranges, but am I correct in understanding that M855 or M193 would not be much off within 200 yards if sighted in for SMK? As you would still be using the donut and not the grid? |
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Question for this:
For a Flattop 16" firing 75gr OTM
Sight in 1.1" high at 100. You'll be 1" high at 200, dead on at 300 and MOA until 600 where you will be 7" lower than the BDC. I'm planning on re-sighting my TA31F on a Larue mount with 75gr TAP. Can I still zero at 25m then just confirm if I'm good at 100m later on? The range I go to only goes to 100 yards max. |
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Originally Posted By El_Pharmaceutico:
in this image trijcon has the TA11F with a 20" barrel, but in post #2 it says the TA11F was calibrated using a 14.5" barrel (and M855 + Flattop mount). In post #4 it says 20" barrels were carry handle calibrated. So is this 14.5" flat and 855, or 20" carry and 193? It's confusing, I wish they would just post exactly how each model was calibrated. Post #4 was originally written in 2003, when the selection of ACOGs and reticles was much less than it is now. I would rely on Trijicon's information since it is A) from Trijicon and B) more recent. |
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Originally Posted By taseal:
Bringing back an old thread, but it's really the only place to put it.... I checked my M855 speeds today, and I got an avg of 2990 out of 16 inch barrel. I believe 14.5 is 2900... now I *think* they used 2970 to set the BDC on the TA01NSN, so I should be ok I guess. the FAQ says the diff is minimal, but 100fps is a big diff I think, no? At 600yds, the difference between 2,900fps and 2970fps at the muzzle translates into an extra 7" drop. From a practical perspective (which is the perspective the chart was created from), that means the difference in drop between the two rounds at 600yds is less than the width of the crosshair. |
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Originally Posted By ad_nauseam:
Given TA11C is the best for heavy 77 gr SMK, etc. on a 16" 1/8 flattop, how badly would M855 deviate if sighted in for 77gr? I never had much luck with M855 at longer ranges, but am I correct in understanding that M855 or M193 would not be much off within 200 yards if sighted in for SMK? As you would still be using the donut and not the grid? The best way to figure this out is with a ballistics calculator as I outlined earlier in the thread; but I generally find that the differences in various .223 ammo at less than 200yds are minimal from a practical shooting perspective. |
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Originally Posted By GreatLoner:
Question for this: For a Flattop 16" firing 75gr OTM
Sight in 1.1" high at 100. You'll be 1" high at 200, dead on at 300 and MOA until 600 where you will be 7" lower than the BDC. I'm planning on re-sighting my TA31F on a Larue mount with 75gr TAP. Can I still zero at 25m then just confirm if I'm good at 100m later on? The range I go to only goes to 100 yards max. Sight in dead on at 25m using the 300m aiming point and you should be close enough that you won't have to adjust much at longer ranges. |
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Just one more comment, a lot of the information in the ACOG BDC Chart is dated now and over 8 years old. Rather than rely on the chart for anything but a hasty "get me close" zero, I would instead get a ballistics calculator, your particular ammo data, and use the information from this thread to calculate a trajectory that works best for you - and then share that information here.
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EDIT: It gets worse. I called Trijicon and they gave me the actual MOA values of the reticle on the TA11F, and I can't for the life of me figure out how they got those values.
According to Trijicon: 100m: 0 200m: 2 MOA 300m: 4.4 MOA 400m: 7.8 MOA 500m: 12.6 MOA 600m 18.6 MOA 700m: 26.4 MOA 800m: 35.8 MOA What am I doing wrong? ===================================================================================== Sorry for the noob post, but I don't understand why––with the same data and the same JBM calculator––I often get wildly different results than others. So for instance, someone else posted these drop values: 100: 0 inches, 0 MOA 200: 2.4 inches, 1.5 MOA 300: 11.1 inches, 3.5 MOA 400: 27.8 inches, 6.6 MOA 500: 54.7 inches, 10.5 MOA 600: 95.2 inches, 15.1 MOA 700: 153.3 inches, 20.9 MOA 800: 234.3 inches, 28.0 MOA Now when I plug everything in using Trijicon's values for the TA11F (I confirmed with Trijicon CS today) of being zeroed for a 62gr bullet at 3050 FPS from a 20" barrel, and using a BC of .304, I get this: 100:-0.0in-0.0 MOA 200:-3.2in-1.4 MOA 300:-13.7in-4.0 MOA 400:-33.7in-7.4 MOA 500:-66.4in-11.6 MOA 600:-116.1in-16.9 MOA 700:-188.6in-23.5 MOA 800:-290.9in-31.7 MOA Very different values. I can't say with 100% certainty that I'm not screwing something up (I could have sworn I've run it in the past and gotten different values, which would imply that I'm making mistakes inputting data into the calculator), but I'm triplechecking everything. Any suggestions/help? |
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This is direct from Trijicon CS today. I hadn't found this information anywhere on the web. Plug it into your ballistic reticle calculator and know where you are hitting for any load.
TA11E (308 Flattop) is in fact calibrated for 175 gr ammo at 2651 fps. Elsewhere someone had incorrectly posted that it was for a 168 gr. projectile. 100 meter ZERO is tip of Chevron 2.2 moa to inside tip of Chevron, 200 m 4.7 moa to tip of BDC, 300 m 8.3 to 400 m 12.4 to 500 m 17.0 to 600 m 22.3 to 700 m 28.4 to 800 m |
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Good stuff..
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If you want to use a Ta11E on a 16" 308 weapon and want to shoot 147gr, you need to zero at 45 yards to match the BDC pretty closely to 500 yards. After that it goes to crap pretty quickly
range BDC 147gr/2250 difference 0 -2.5 -2.5 0 50 -0.6 0.2 -0.8 100 0 1.5 -1.5 150 -0.8 1.1 -1.9 200 -3.2 -1 -2.2 250 -7.2 -5 -2.2 300 -13 -11.1 -1.9 350 -20.7 -19.6 -1.1 400 -30.5 -30.7 0.2 450 -42.5 -44.6 2.1 500 -57 -61.8 4.8 550 -74.1 -82.5 8.4 600 -94.1 -107.1 13 650 -117.2 -136.2 19 700 -143.8 -170 26.2 750 -174.1 -209.3 35.2 800 -208.5 -254.4 45.9 850 -247.3 -306 58.7 900 -291 -364.5 73.5 950 -339.9 -430.5 90.6 1000 -394.5 -504.6 110.1 |
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The king of the vultures would be no less bent upon preying upon the flock than any of the minor harpies, it was indispensable to be in a perpetual attitude of defence against his beak and claws
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This is helpful.
Thank you. |
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Originally Posted By swingset:
I feel like printing this thread out on some quality paper, so I can go wipe my ass with it. |
First thank you very much for all your time and effort put into this thread OP.
My question just to be certain: I have a TA33 on a flat top 14.5 inch and use M193. Sight in at at 50 yards? Thanks, Jim |
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Proud Member of Team Ranstad
If Magpul sold boots with VFGs as heels, half of GD would be strutting around in them like a bunch of princesses. I am busy watching Spongebob motherfucker |
This all blows my mind and after zeroing and shooting yesterday I question whether the ACOG is for me.
TA31F mounted on a 16" Armalite (AR15) I first noticed something odd this past deer season, I took a deer down easily at 125 yards but when I shot at another later in the season at 275 yards completely missed, the deer were patient and were allowing me to walk my rounds in..until they caught on... So yesterday at the range I checked my zero at 100 yards.. perfect.. shooting at 200 was pretty good.. 300 I couldn't hit the 12 x 12 steel target consistently if at all sometimes... Using BH Blue Box... Anyone have any recommendations ?? |
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Originally Posted By testedone:
This all blows my mind and after zeroing and shooting yesterday I question whether the ACOG is for me. TA31F mounted on a 16" Armalite (AR15) I first noticed something odd this past deer season, I took a deer down easily at 125 yards but when I shot at another later in the season at 275 yards completely missed, the deer were patient and were allowing me to walk my rounds in..until they caught on... So yesterday at the range I checked my zero at 100 yards.. perfect.. shooting at 200 was pretty good.. 300 I couldn't hit the 12 x 12 steel target consistently if at all sometimes... Using BH Blue Box... Anyone have any recommendations ?? View Quote Shouldn't the TA31F be zeroed at 100 meters instead of 100 yards? I also think the BDC is calibrated in meters, no? |
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Scepticism is an exercise, not a life; it is a discipline fit to purify the mind of prejudice and render it all the more apt, when the time comes, to believe and to act wisely. -- George Santayana
Never mistake a clear view for a short distance. |
yes you are correct, kind of hard to zero at 100 meters when every range I have ever been to is in yards not meters but your point is not lost..
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I am using Strelok also (Android) my numbers come out a little different.
But, I did go to the range today and was really close to what you show below but I only went out to 300 & 500... What version of Strelok are you using mine deosn't give me the TA31F, however it does give me - Chevron, Trijicon Edit - Download Strelok + and I have that reticle What do you have as scope height I am mounted on a LaRue LT100 |
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I have height over bore at 2.7" (1.2" from bore to rail + 1.5" from rail to centerline of optic).
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I've been using the information posted here since I first found it, but I have a question maybe someone can help with.
I have a TA33 5.56 ACOG and I have it zeroed on a flat-top 16" upper. Everything is good in my life. But, is there a way I can determine the offset/holds on the reticle if I wanted to shoot 75gr ammo? (note: not zero with 75gr ammo, just shoot it). Thanks guys! |
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Thanks for the confirm. It only changed my drops by a yard or so. For your drops, I'm guessing your ammo is slower than 2850fps.
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Here is the link for BH
BH Ammo (Reloads) .223 Remington 36 Gr. Varmint Grenade Velocity: 3750 FPS 40 Gr. Hornady V-MAX ® Velocity: 3600 FPS 50 Gr. Hornady V-MAX ® Available in Molycoat Velocity: 3300 FPS 52 Gr. Match HPAvailable in Molycoat Velocity: 3250 FPS 55 Gr. Full Metal Jacket Velocity: 3200 FPS 55 Gr. Soft Point Velocity: 3200 FPS 60 Gr. Soft Point Velocity: 3100 FPS 60 Gr. Hornady V-MAX ® Available in Molycoat Velocity: 3100 FPS 68 Gr. Heavy Match HPAvailable in Molycoat Velocity: 2850 FPS 69 Gr. Sierra MatchKingAvailable in Molycoat Velocity: 2850 FPS 75 Gr. Heavy Match HPAvailable in Molycoat Velocity: 2750 FPS 77 Gr. Sierra MatchKing HPAvailable in Molycoat Velocity: 2750 FPS Originally Posted By SuperSet72:
Thanks for the confirm. It only changed my drops by a yard or so. For your drops, I'm guessing your ammo is slower than 2850fps. View Quote |
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