The Pulsar Forward DFA75 is a state of the art digital night vision device which is front mounted to your dayscope to convert your day optics into a night vision riflescope.
Using a cover ring adaptor system you attach the adaptor to your riflescope choosing either the 42, 50 or 56mm adaptor, allowing you to quickly and easily swap your DFA75 from rifle to rifle with no loss of zero.
In this video Byron Pace takes us through the set up step by step and shows us how to get the very best results from the Pulsar Forward DFA75 MK2.
Finding himself delving deeper into the world of night vision, Byron Pace explains how to set up the DFA75- Original DFA75 Review and Guide
This time last year, if you had asked me about night vision, I would have shrugged my shoulders and relented at the fact I didn’t know very much. Lots has changed since then however, as my hand was forced when it came to learning the ins and outs of the latest NV. With a call from Scott Country offering some of their kit for use in The Shooting Show, I had to get to grips with the latest offerings for nocturnal wonderings.
One of the latest units I have had on test is the new NV front-mounted sight from Pulsar. Their N750 dedicated night sight is now well established, and having used it quite extensively, I know what incredible capabilities that unit offers for the money. The down side of it is like any dedicated NV unit, in that you have to sacrifice a rifle solely for the hours of darkness. The new Pulsar DFA75 gets around this, as it attaches to the front of your day scope, and offers you the best of both worlds.
Night Vision guru Mike Powell is reviewing the unit this month as well, so I will not venture to repeat any information. However, this particular NV is a little tricky to set up, and having struggled initially myself, it seems there are plenty of hunters out there who have shared the same frustrating experience in getting the unit to play ball. After spending quite some considerable time playing with the DFA75, I finally cracked it with some help; no thanks to the rather confusing instructions. So here are a few pointers to help you set up the DFA75 and understand how it works.
The first important thing to note is that the scope attachment needs to remain on the scope once fitted, only removing the DFA via the bayonet fitting. Only this way will you be able to maintain the zero setting. Further to that, ensure that you clamp the scope attachment as tight as it will go. This must not move. With that sorted, you now need to get your head around how the DFA75 works.
Being a front mounted unit, you will notice that the lens of the NV is not in line with the objective lens of your scope. If you were to draw two lines of sight between the two optics (Diagram 1), you would end up with parallel lines 4.3cm apart, which is the distance between the centre of the two lenses. If you were to set up the NV to have a straight line of sight, you bullet would always land 4.3cm lower than you expect it to be. This is because you are actually viewing the world through the DFA lens mounted higher than your scope.
Now, the first way to set up your unit is to actually zero it to a specific distance. So let us take 50m. Essentially what you are doing here, is angling the line of sight from the NV unit, to transect the line of sight from your scope (which is already zeroed) at a distance of 50m. Once you achieve a 50m zero (we will go through that process shortly) that is not quite the end. As a result of your DFA unit looking down on the line of sight of your scope, every shot you fire at a distance shorter than 50m will land low, and any shot fired at a target further than 50m will land high. This is quite counter intuitive to how we understand bullet drop, and the caveat is that over a long enough distance, the bullet drop would eventually compensate for NV angle and you would be back on target.
Thinking logically, the reason for this result is that although you think you are on target at say 25m, your NV line of sight is still sitting above your scope line of sight, and as a result of this your barrel will be lined up lower than you expect. Hence, the bullet drops low. At a distance of 75m, you are viewing the world below the line of sight of your scope. As a result of this, where the bullet impacts will be higher than you expect (i.e. where the scope line of sight is pointing. See Diagram 2)
What is good news is that the hold over and hold under are equal and predictable. As the diagram shows, a 50m zero leads to a 2.15cm low shot placement at 25m and the reverse at 75m. What is important to note here, is that there is considerable merit is zeroing your unit at a greater distance, as the angle which the DFA75 has to look down towards the scopes line of sight is less, and as a result, the hold over and under is smaller. You can see this in the Diagram 3. Extending the zero point to 100m, you end up with the same 2.15cm hold over and under, but at the extended range of 50m and 150m. With a 5cm kill zone, this would essentially mean you could aim in the same place out to 150m for a kill shot.
The zeroing of the unit is similar to the N750, with a slight change. What I say next will only really be of benefit to those with a DFA75, so you can skip this paragraph otherwise. The first zero setting is merely to calibrate the DFA to line up with the cross hairs in your scope. This first stage also allows you to check you unit hasn’t shifted, as the ‘X’ on the screen should match the cross hair centre. The second zero setting is like the one shot zero system in the N750. Simply place the ‘X’ over where your bullet landed, and the next shot should be on target. However, be sure to come out of the zero menu by depressing the function button (the screen should jump for re-zero). Fail to do this and nothing will have been achieved.
The above zero method is what I would suggest, however there is one further way, and that is to set the line of sight parallel as I described at the start. In this way all shots will be 4.3cm low, and so require 4.3cm of holdover (ignoring bullet drop). This I find to be the least effective method.
Lastly, it is of great benefit to start your initial zero at about 20yds, otherwise you have trouble hitting paper at all. From there, work back to the zero range.
You will probably find yourself needing to read through this again to understand fully, but once you have grasped the concept it, it will seem much more straight forward.