Thread: Duplex reticles

Hi members
This may sound like a rookie question but here goes
How do you use duplex reticles for hold over at longer ranges. Personally I prefer reticles with holdovers to allow versatility for quick shots at longer ranges.(300 to 400m)
I'm a quite an european optics fanboy but most come predominately with duplex reticles. My VX5 firedot is same scenario. Yes you can dial but don't like slugging exposed turrets through scrub,also it takes precious seconds on a quick shot.
Anything I'm missing here except for guestimating?

Yes,there is something.... If your even half clever and are using a rifle chucking a projectile somewhere above say 2700fps if you sight it in to hit 2-3" high at hundy yards.you point and shoot out to 300+-...... Old school thinking called the rule of three..for 3" high at hundy. 3-400 is big variation without rangefinder.... You can of course measure the length of crosshairs against say a fence post at your 300---400 and use that measurements to do your maths... Eg at 400 your drop MIGHT be half way to thick bit....

If you have the bullet information put it through a ballistic app that can show you what it looks like through the scope and it will give you an idea how high to hold.. if you're having to take the reticle off the animal than it's proberly to far to make a reliable kill.

Similar to Micky, Depending on what cartridge you are using- for me it was 270. 3 inch high at 100, gave a rough point blank range too 300. Then centre cross on the spine at 400 and note where thick part of post started and was on animal, which you could raise for a hold, probably close to spine again for another 50 odd yards.

Later on we got a bit more technical and confirmed our holds at different ranges on gongs.

If its a quick shot in the bush you won't need to dial.
most hunting calibers if zero'd at 200 mtr are minute of deer to 300 mtr so no dialing needed.

If you are taking a longer shot you generally have time to studied the animal, get comfortable and on to a good rest, range find it etc.
assuming you have previously set you scope adjuster to zero its only a short job to wind it up to whatever you need. have a card with 25 mtr intervals on it.
Z

The 3030 reticle was a popular one. 15 inches from cross hair to thick post 30 inches from post to post at 100 yds, sort of an early ranging system. I think there's still one in my retired scope bin along with a few post and wires.

before I dialled I used 200 yard zero,300 yards was top of shoulder,400 yards was beer bottle over shoulder.that was for a 7 mag.

Originally Posted by Micky Duck

Yes,there is something.... If your even half clever and are using a rifle chucking a projectile somewhere above say 2700fps if you sight it in to hit 2-3" high at hundy yards.you point and shoot out to 300+-...... Old school thinking called the rule of three..for 3" high at hundy. 3-400 is big variation without rangefinder.... You can of course measure the length of crosshairs against say a fence post at your 300---400 and use that measurements to do your maths... Eg at 400 your drop MIGHT be half way to thick bit....

Tthis.

I was running these numbers for various calibres helping someone set up a back drop for a range situation. He wanted to make the back drop large enough to catch "all" calibres. What I noticed is that out to 300 or 400m, bullet size or calibre made little difference- BUT muzzle velocity did. If they were doing 2650 to 2900 fps the rule of three worked very well though most were 2 inches high at 100, zero at 200 and 3 inches low at 300. To make this easy, if you see a 8 inch gong and you aim at the centre or slightly above then from the muzzle all the way out to 300m - aim at the centre and you will hit it within 3 inches from centre. If you feel its a longer shot Aim closer to the top as anything past 200m will be below the cross hair.

Going out past 300m the BC of the bulllet maintaining momentum / drag etc started to separate the various weights / calibres out, if using 303 or similar at 2500fps just allow for 90m,180m and 270m for the same performance. My load runs at 2050fps so is more like 80,160,240m and is just over 6 inches low at 300m.

With deer vitals in the chest being close to 12 inches (dinner plate size) there is even room for shooter variation / wobble...but as with all things, you should practise / confirm on targets first and not the animals...

Pigplex reticle is quite nice. Duplex reticles are really only good for point and shoot type of hunting

With the centre of the cross hairs on a Duplex Reticle zeroed for whatever distance, you can use the top of the thick part of the reticle as an aiming point and change it based on the magnification setting on the scope - but you'll probably need a Ballistic Solver or be a Maths whizz to figure it out, and it will be there or thereabouts dependent upon how accurate the scopes magnification dial is.

This Duplex Reticles thicc piece gives a zero of 258m when on Seven Power...




On Three Power its 393m.





Those of you who have the watched the same videos I have will knnow this as 'Poor Mans Horus'

If your using a duplex and not dialing for elevation, the reality is you max range is about 280-300m for deer size targets (assuming a modern high velocity cartridge, and a 2-3" high zero at 100m)

I prefer SFP scopes for my hunting rifles, so don't use the BDC in the reticles as I am almost never on max power (the BDC values change with magnification in SFP scopes. I buy only scopes with dialling elevation turrets. I make custom turret tapes with drop data on them so I can just range, then run the turret up to that number and shoot. No checking charts or ballistic calculators. I have found this to be the most convenient by far for hunting situations.

There are two sorts of setup for reticles:
First focal plane (FFP) where the reticle appears to increase in size as you increase magnification and the target appears bigger, but has the same dimensions on target. A common basic version has dots that are 10 cm apart at 100m at whatever magnification you use. That is called a “Mil Dot”. It makes it relatively easy yo estimate how much to hold over at different ranges if you dont dial the elevation adjustment.
Second focal plane (SFP) systems have the reticle stay st the same apparent size as the target gets bigger when you change magnification. The common basic SFP reticle is the “Duplex” which has thicker crosshairs ouside and thinner crosshairs in the middle. For example, looking at the Leupold reticles https://www.leupold.com/media/binary...cle/Duplex.pdf we see that the duplex in the 3-9x Freedom scope has a space of 15.6” at 100yd at 3x. So, at 6x the gap will be 7.8”. At 9x it is 5.9”. This is why it is very difficult to use SFP duplex reticles for holdover and people usually dial the elevation or estimate the holdover (usually inches) on the target.

or you guestimate kentucky windage..eg middle shoulder,high on shoulder,aim for spine..get closer in that order...the rangefinder sure has made life more simple on one hand,and more complex on the other.

Originally Posted by fernleaf

With the centre of the cross hairs on a Duplex Reticle zeroed for whatever distance, you can use the top of the thick part of the reticle as an aiming point and change it based on the magnification setting on the scope - but you'll probably need a Ballistic Solver or be a Maths whizz to figure it out, and it will be there or thereabouts dependent upon how accurate the scopes magnification dial is.

This Duplex Reticles thicc piece gives a zero of 258m when on Seven Power...

Attachment 288822


On Three Power its 393m.


Attachment 288817


Those of you who have the watched the same videos I have will knnow this as 'Poor Mans Horus'

that is completely LOAD DEPENDANT.... eg if we round numbers for simplicity and have 270win throwing 130grn at about 3000 fps and have it zeroed 3" high at hundy it will be plurry near smack on again at around 270 yards...... easy numbers to remember.so your 7x dead on for 258 will have me shooting over the top by 50plus cm..nearly 2 feet!!!! if I had used the 3x it would be close to ok...must check that one out....but will not work if I realign scope so have X hairs instead of usual orientation .....plurry handy in bush where much is verticle and little on 45 lol

Its just not that complicated.

If you sight in 3 inch high at 100, then it doesn't matter what power setting out to well past where you will easily be able to use the max magnification on any scope up to probably 18x.

Then just use the max for a personally standardised set of marks, being your centre cross high on spine or for further you vertical post on shoulder or spine. That way you are never having to hold over out to pretty reasonable distances.