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

Zero for 100, make a chart with the distances each reticle graduation corresponds to, hold between them for actual ranges that fall between, have an understanding of "danger space", shoot stuff


Once you go smoke a few plates at 300-400 with it you'll realise that it's not that complicated

Your crossbars with a 100y zero are close enough to 200/300 that it won't matter in the real world

Originally Posted by vulcannz

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

PBR:


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.

That’s more useful for a duplex reticle it wouldn’t be taking advantage of the hold over reticle on the scope the op is referring to

It's a bit goofy but it's a useful illustration.

When you're looking at a deer at 400y (360m), it will look something like this (aiming point 3mil down).

Your crossbars are 1mil spacing, same as the dots in this reticle.

Note at 400y you have a pretty large vertical margin for error so it doesn't matter too much if your 400y zero is actually 3.2 mil down.

My Z3 and Z5 Swarovskis all have BDC reticles. All rifles on which they are mounted I have zeroed at 250 yds, giving me pretty much hold and shoot out to a bit more than 300 yds ( relative to velocity ). After I got them zeroed at 250 yds with the chosen load and the magnification turned up to what I would use for distance shooting ( either 10 or 12 X ) I shot targets at 300, 350 and 400 yds and noted the POI's on a little diagram which I keep as a reference for when I shoot the particular rifle next. I found there is not massive difference in most loads out to about 350 yds but differences become bigger further out. I limit my shots to 400 yds or so max so as not to make distance shooting to much work for my brain !

Originally Posted by gimp

It's a bit goofy but it's a useful illustration.

When you're looking at a deer at 400y (360m), it will look something like this (aiming point 3mil down).

Your crossbars are 1mil spacing, same as the dots in this reticle.

Note at 400y you have a pretty large vertical margin for error so it doesn't matter too much if your 400y zero is actually 3.2 mil down.

Attachment 243785

I thought they were in MOA only because of the app giving either yards meters or MOA

Originally Posted by Kelton

I thought they were in MOA only because of the app giving either yards meters or MOA

"It's a mil-dot reticle with half mil hashes ..."

Rodger led a stray by the app makes sense

"hundreds minus 1.5" is a pretty good rule of thumb to remember drops plus or minus 1 click for moderate cased cartridges with a decent BC bullet (.4-.6 at 2700-2800fps) out to 400-500m

(metres, mils, 100m zero).

Another thought,
If your scope is a second focal plane unit then your calculated drops will only be accurate for one power so if you are a power ring twirler you have another problem. If you can manage that then if you zero your scope for a maximum point blank range to suit you calculate your range drops. Round them to the nearest 5 or ten yards and make your table. Deer do not pop out at round number ranges so you will have to estimate between the dots anyway. For me I would do it in metres rather than yards but then I have spent the last 50 years working in metric.
Regards Grandpamac.

Originally Posted by grandpamac

Another thought,
If your scope is a second focal plane unit then your calculated drops will only be accurate for one power so if you are a power ring twirler you have another problem. If you can manage that then if you zero your scope for a maximum point blank range to suit you calculate your range drops. Round them to the nearest 5 or ten yards and make your table. Deer do not pop out at round number ranges so you will have to estimate between the dots anyway. For me I would do it in metres rather than yards but then I have spent the last 50 years working in metric.
Regards Grandpamac.

@grandpamac it's a 3-10x power scope - if you are using the reticle dots/hashes you're are going to be on max power anyway so that's not an actual problem.

The Swarovski app does have a function where it shows the change in relative distances as you change depending on the zoom power, so in theory if you use the app when shooting you could use a lesser zoom power and the values increase to compensate.

As for using yards, as the rangefinder (geovid) is only yards that'll be me until I can afford a newer model.

A question. If you zero the main crosshair on a BDC reticle at 100 metres (or whatever), then measure how high the bullet impacts when using the lower marks at the same distance, can you then calculate the distance that corresponds to each mark?

Hope that makes sense

Originally Posted by Kimber 7mm-08

The Swarovski app does have a function where it shows the change in relative distances as you change depending on the zoom power, so in theory if you use the app when shooting you could use a lesser zoom power and the values increase to compensate.

As for using yards, as the rangefinder (geovid) is only yards that'll be me until I can afford a newer model.

Greetings @Kimber 7mm-08,
The info that @Shamus_ posted on the reticle is most interesting. The mrad based reticle can be used for for identifying shots that are within the point blank range that can be taken without ranging by bracketing the animal with the reticle. I assume that the blurb had been put out for the US market due to mis spelling metre and more surprisingly getting mil and milliradians (mrad) scrambled. It appears that the scope is in milliradians, 100mm at 100 metres rather than mils, 98mm at 100 metres. A small difference perhaps but a difference none the less.
Regards Grandpamac.

Originally Posted by MB

A question. If you zero the main crosshair on a BDC reticle at 100 metres (or whatever), then measure how high the bullet impacts when using the lower marks at the same distance, can you then calculate the distance that corresponds to each mark?

Hope that makes sense

yes......... by going onto a ballistics app like pointblank and keep changing the zeroed for distance untill the amount high your impacts are match what it says...EG zeroed for 200 it will be 1.5" high at hundred zeroed for 600 it will be 10" high at hundred....
so if you useing say the 4th cross hair down and it hits say 7" high you keep changing zeroed for range untill something clicks and you have 7" high at hundy
make sence???