Thread: How do I set up and use a BRH (or BDC style) reticle?

No such thing as a stupid question apparently, so here goes....

I just acquired a Swarovski Z3 3-10 with a BRH reticle as I want to try it out on my 17inch Kimber Montana 308 so it is not just a bush gun (currently using a Leupold 1.25-4 VXR) and can be used in open areas with a bit more confidence than the 1.25-4 scope can give.

Now, here are my questions.

1. When run the numbers in the Swarovski ballistic app with a 100yd zero I get a the following distance information which are a bit all over the show in terms of easy to remember distances out to about 450yds (e.g.179,237,289,336,379,420, 457):



If I adjust the zero to 134yds I can then get the BRH reticle to very closely (1-6 yards) correspond to 200, 250,300,350 and 400 before the numbers start to get a bit more random as shown below:




I think that the 134 yard zero (or more precisely the 200yd zero for the uppermost BRH crosshair) will give me largely a point and shoot rifle at bush distances and then provide easy to remember distances out to 400yds which for the current factory whitetail ammo I shoot equates to a velocity of 1743fps and 1012ft/lbs of energy. Realistically I'd likely be limiting shot to 400 and under in any event.

How do you guys use the BRH or other BDC type reticles? Do to try and 'true' them up to nice easy to remember numbers by adjusting the zero, or just go, plus or minus 20-30m/yards is close enough at those distances on a deer and call it good. What I am trying to achieve is something that my 10 year old son and I can use with confidence (should we ever find a deer!!!) that is easy to remember in terms of distances!

2. In addition to the above, in the real world a deer is not going to generally be at the set BRH distances. So what do you guys do in those cases? For example a deer walks out of the bush edge and stands broadside at 375yards. In the above example (with a 134yd zero) I know I have a verified BRH distance at 350 and 400yds. Do I align the crosshair at the midpoint between the 350 and 400 marks for an approximate 375 distance, or pick the 350 mark and adjust the aim up a bit to allow for the drop , or aim lower with the 400 mark as the bullet will impact higher, or just pick either and call it good as either distance is approximately 5-6 inches (+/-) at that distance and good enough? Personally I want as much confidence as possible (both for myself, eventually my son when he gets onto a deer and most importantly for the quick dispatch of the animal) that I have done everything possible to get the bullet into the deer accurately and not wonder if I have misjudged something should things not go as planned with the shot.

Hopefully the above makes sense, and hopefully the questions are not too 'stupid'.

what happens if you poke in a 200 yard zero??...... personally I would try that and print off and laminate what it works out as and stick that on the stock.
by poking in 200 yard zero you will be point n shoot out to 250ish before even having to think about it.

Originally Posted by Micky Duck

what happens if you poke in a 200 yard zero??...... personally I would try that and print off and laminate what it works out as and stick that on the stock.
by poking in 200 yard zero you will be point n shoot out to 250ish before even having to think about it.

Pretty spot on also!

I may have it completely wrong, however my understanding of BDC reticles is the the hash marks loosely correspond to 100, 200, 300, 400 with a 100 yard zero etc if using normal loads and bullet weights and using a cartridge compatible with the particular reticle.

It's unlikely they will line up exactly but they do get surprisingly close if you look at the moa numbers.
Not as precise as dialing but better than estimating/guestimating hold over.

I've tried it out to 400yards and was way closer than I expected.

Old adage .308 3 inches high at 100, zero at 200, 3 inches low at 250 metrify if you wish. I've done that and initally printed it with a felt pen on the stock but now know it off by heart. Holding mid way between hash marks pretty much covers the intermediate distances well enough for hunting.

I just run a 100yd zero and have that screen shot on my phone being meaning to print it and keep it in bino harness but I know the first dot is spot on 250 and that’s near my limit with that rifle anyway have found it very accurate

Some ex military snipers using mils zero their rifles so those hash marks are really close at 100 yards increments, after 5-600 yards it starts to get a bit fuzzy

What happens if you use meters instead of yrds ?

It's a mil-dot reticle with half mil hashes and you can easily extrapolate between the reticle dots and hashes to .25 mil and less. I run a 200m zero and just hold for whatever amount of mils I need according to my drop chart (or in reality the ballistic solution out of my rangefinder). This is what works for me at the ranges I shoot.

Originally Posted by Ground Control

What happens if you use meters instead of yrds ?

100m and 200m zeros above. I have an older set of geovids that only range in yards, so will be sticking with yards for the time being.

Every time I've looked at setting mine up I end up having the same issue as yourself and figure dialling is just easier, especially when a 25m difference at say 400m results in 6 inch difference in drop (and that's with 7mmRM so 308 will drop even more) you need to be pretty accurate

Have you chronographed the ammo to actually see how fast it is in your Rifle because that ballistic app is probably using Factory listed velocities which could be quite different to what your Rifle is doing .

Originally Posted by Ground Control

Have you chronographed the ammo to actually see how fast it is in your Rifle because that ballistic app is probably using Factory listed velocities which could be quite different to what your Rifle is doing .

Yes, the velocity I inputted was verified by a chronograph.

Just realised theirs blank stickers in the box to mark your own distances on

You need to figure out what your desired point blank range is (aka point blanc range or PBR).

PBR:

Here is an example: Let's say you are deer hunting. The vital zone of deer is roughly 8 inches. Using the calculator it tells you that you should zero your rifle at 250 yards and that the MPBR is 300 yards. That means that if you aim at the center of the vital zone of a deer at any range between 0 and 300 yards, you will hit the vital zone. This means that you do not need to worry about any bullet drop or holding over if the animal is within the MPBR.

One description of the MPBR concept that has been used a lot over the years is to visualize shooting with your barrel centered inside an imaginary pipe. The size of the target determines the size of the pipe. The maximum point blank range is the furthest distance at which a bullet fired from a rifle will stay inside the pipe without hitting the top or the bottom.

There is a great tool here to calculate it (where I stole the above quote from), this has your ammos parameters in already. I've set it with a 6 inch vital zone. Note you also need to get your scope height right, I just guessed at 2 inches.

https://shooterscalculator.com/point...2820&sh=2&ts=6

Once you understand PBR then it all gets easy to decide your zeros.