Bushnell's AR Optics 4.5-18x40 223BDC reticle subtensions

[bladeracer]

Got a response back from Bushnell just now.
I specifically asked about the 223BDC but the document doesn't seem to specify 223 or 308 - strange.
EDIT: Bushnell have confirmed that these are indeed the 223BDC - .308 is "slightly different".

[Gwion]

Probably the same scope with a different badge so that it can be 'matched' to the rifle. IE: marketing ploy.

Edit: strange spacing a on the subtensions, though!

[albat]

I have this scope mounted on my 243 works ok for this calibre as it closely replicates the 55grain trajectory with a 90 grain 243 pill find the dots too big though decent glas for the price and but its pretty heavy

[Gwion]

Just plug your load data into a decent ballistics calc and then note down what ranges the stadia match your load.

[bladeracer]

Probably the same scope with a different badge so that it can be 'matched' to the rifle. IE: marketing ploy.

Edit: strange spacing a on the subtensions, though!

It's a Bullet Drop Compensating reticle so the subtensions get larger with range.
It's pretty close to what I had calculated them to be.
100yd -zero
200yd –1.56MoA (actual 1.7MoA)
300yd –4.11MoA (actual 4.4MoA)
400yd –7.43MoA (actual 7.6MoA)
500yd –11.7MoA (actual 11.4MoA)
600yd –17.17MoA (actual 15.4MoA)

[Gwion]

Technically the subtensions or stadia stay the same as an angular reading. But yeah, I get what you're saying.

However, this is only true for a certain magnification. Vortex has a ballistics calculator that allows you to name you reticle, load your muzzle velocity data, bullet data, etc. and see where the stadia read at different magnifications. I played around with it a quite a bit a year or two ago but now I hardly use the BDC stadia and just try to keep shots to MPBR. I do occasionally use it to guesstimate a little drop but if the shot is far enough that I have to go past the first stadia, I just leave it. I'm mainly shooting wallaby as pest control so I've figured out an average that kill them quick. Only go out to 70-80m with the 22 and maybe 180m with the 223 (full load) or 120m max if shooting with trail boss load.

My main point was that any BDC, being an angular reading, will only be correct at various ranges depending on the external ballistics of the round you are using.

It's all just a ball park guess once you factor in vagaries such as judging range, scope mag setting, muzzle velocity, bullet weight and BC. Know your kill zones and what range and conditions you are capable of hitting them.

That said, it is good to know your gear.

[bladeracer]

Technically the subtensions or stadia stay the same as an angular reading. But yeah, I get what you're saying.

However, this is only true for a certain magnification. Vortex has a ballistics calculator that allows you to name you reticle, load your muzzle velocity data, bullet data, etc. and see where the stadia read at different magnifications. I played around with it a quite a bit a year or two ago but now I hardly use the BDC stadia and just try to keep shots to MPBR. I do occasionally use it to guesstimate a little drop but if the shot is far enough that I have to go past the first stadia, I just leave it. I'm mainly shooting wallaby as pest control so I've figured out an average that kill them quick. Only go out to 70-80m with the 22 and maybe 180m with the 223 (full load) or 120m max if shooting with trail boss load.

My main point was that any BDC, being an angular reading, will only be correct at various ranges depending on the external ballistics of the round you are using.

It's all just a ball park guess once you factor in vagaries such as judging range, scope mag setting, muzzle velocity, bullet weight and BC. Know your kill zones and what range and conditions you are capable of hitting them.

That said, it is good to know your gear.

Is wallaby the same as 'roo in requiring head shots only?

For Bushnell the BDC is only correct at full power - 18x. But the hold-over marks are at half the MoA at 9-power, and one-quarter at 4.5-power.

[Gwion]

Guidelines for pest control on wallaby stipulate a head shot to be best but it is just a guideline. I'll find the link at some stage. Wallaby are listed as game in Tas. As long as you've got a hunting licence you can shoot them during daylight hours. To spotlight them you need to be shooting on a property with a crop protection permit in place. Otherwise, spotlighting is illegal in Tas.

[AusTac]

Ok so i think this is going to have an obvious answer but here it goes, how would you work out the moa hash marks on your scope as in the distances ( moa ) apart? And then say you know your hash marks what software are we all using?

[bladeracer]

Ok so i think this is going to have an obvious answer but here it goes, how would you work out the moa hash marks on your scope as in the distances ( moa ) apart? And then say you know your hash marks what software are we all using?

I stick up an A4 (210x297mm) sheet of paper at 100m to get a rough idea of the MoA of the hash marks.
For this particular BDC I used rough BC and velocity figures for NATO ammo which gave me the figures I was using, but I wanted to know exactly what figures Bushnell use for the reticle as I have six of these scopes.

Pretty much all ballistics software uses the same formulas.
This one is pretty simple, but really not set up for metric.
http://www.shooterscalculator.com/ballistic-trajectory-chart.php?t=f630255c

Shoot a load at two distances - I do 50m, 100m, 150m and 200m - and measure the trajectory. It should be pretty close to what the software says, provided the BC and velocity are accurate. If you don't know the velocity and/or BC you can tweak those until you find a curve that matches your test shoot.

https://enoughgun.com/forum/viewtopic.php?f=4&t=6555#p99712

[Gwion]

Your scope manufacturer's website should have info page or PDFs on the different reticules they offer and what the subtensions are set at. I have Vortex and Sightron scopes and both these companies have good info online. Vortex also has a ballistics calculator that can be set for your scope and ammo, which makes the whole process pretty easy.

If you don't have a chronograph to measure velocity you can use the method that Bladeracer outlined above to get an idea of your trajectory; this will obviously be a rough idea depending on how accurately you and your rifle/ammo can shoot at any given range. If you don't have access to enough ground to shoot out to 200m, you will just have to go off the listed velocity on you factory ammo.

The bullet or ammo manufacturer's website should also have details re: weight and ballistic coefficient as well as velocity if you are using their factory ammo.

All this will just be ball park unless you have accurate data re: velocity, bullet weight and BC.

Plug all this data into a good ballistics calc; these three i have found to be pretty good and user friendly:

http://appliedballisticsllc.com/
http://www.jbmballistics.com/cgi-bin/jbmtraj-5.1.cgi
http://www.shooterscalculator.com/

Set your trajectory output to read in MOA every 5 or 10yards/meters. I find it helps to limit the extent of the data output to the max range you are likely to shoot; there is no point having a trajectory chart for a 22lr that extends out to 1500m. Then you can read off where the chart matches the MOA on your reticule.

Confirm your findings by shooting some groups at a few different ranges.

Again, all this will only be a broad ball park indication unless you enter accurate data to begin with.

[AusTac]

Thanks for the info fellas, sometimes it helps to hear things in different words, looks like i'll have to shoot it out

[Gwion]

Is wallaby the same as 'roo in requiring head shots only?

For Bushnell the BDC is only correct at full power - 18x. But the hold-over marks are at half the MoA at 9-power, and one-quarter at 4.5-power.

Here is the code of practice for wallaby shooting in Tas.:

http://dpipwe.tas.gov.au/Documents/Wall ... andard.pdf

[bladeracer]

Here is the code of practice for wallaby shooting in Tas.:

http://dpipwe.tas.gov.au/Documents/Wall ... andard.pdf

Thanks Gwion. That actually reads like it was put together by intelligent reasoning and consultation instead or anti-hunting rhetoric and emotion.

[bobnob]

I have the same scope. I mostly leave it set on 10x so I shot a tall target at 10x to find all the subtensions. Here's how they worked out...

[Walt68]

The .223 scope has .223 marked on it, the .308 had .308 marked on it, the box tells you what size projectile it is calibrated for.

[bobnob]

All well and good if the load you're using happens to closely match the MV and ballistic coefficient of the load used to come up with what's written on the box.

[bladeracer]

The .223 scope has .223 marked on it, the .308 had .308 marked on it, the box tells you what size projectile it is calibrated for.

Actually, neither tells you exactly which bullet design or velocity it is calibrated for so it is never going to be precise enough for varminting.
Ignore what they claim it's calibrated for and simply work out what ranges the marks correspond to with your specific load.

[marksman]

so how do you guys rate this scope in general
l've just bought one with the 308 BDC ret sub and would like to hear what you think, if you dont mind

[TassieTiger]

Bought one - sold it soon after. For the money - I think they are ok - would be fine as a knock about hunting scope. Cross hairs were too thick for me for target 223 work.

[marksman]

l've actually bought it to put on the brno 22 rimfire for using the pard nv007 Tassie
You can get them for $235 at the moment so l thought yes its overkill but why not try it
has the side parallax focus so may be worth it

[TassieTiger]

Thought you bought optisan ?
They are reasonably compact now I think of it - so yeah, they might be okay. I sold mine way too cheap, should have kept it for what I ended up selling for.
Does rat pack have any further suggestions RE pard? A friend has a little thing that’s about a 1 x 4, pigplex? He reckons that should work - but I’m thinking some trial and error regardless.

[marksman]

not sure if ratpacker has any other suggestions but the optisan is the EVX 6-24x56 and is going on the 22 dasher for longer shots ect...
l just thought that the bushnell ar may be ok for the 22 rimfire although probably a bit overkill but very cheap
if its no good l'll rap it up and give it to someone for xmas

[Stix]

I dont like mine marksman...
Stiff as hell i tell ya...!!...
Need a set of long handled vice grips on the focus knob to turn it, same with zoom & ocular adjustment isnt real loose either.

Pretty ordinary clarity...i mean good enough for bunny's in daylight, but it does get a bit muddy when cranked up.
i dont know how you'd go with your pard as ive never seen one in real life...

I dont like the big dots & fat reticle...blahh...

I bought it for & its mounted on my old shot out 22-250 to use reduced loads but cant be eff'd carrying the extra rifle with me so ut doesnt get out...i shouldve sold you mine.

Its good value scope for cheap as chips though. ..it wouldve given me a huge thrill if i got to use one of them when i was a kid...

[marksman]

l wish l had of asked before ordering one now but l will have a look on the 22, hopefully it will be ok because of the close range
but l think l should have bought another optisan
cheers for that Stix

[Stix]

Ah yes...close focus...

That makes sense i guess esp for a 22...
You wont have it cranked up to high mag so it may well be just dandy for the purpose...dont be disapointed on my report...