# Firearms and Shooting > Shooting >  Handy BC reference chart

## Hendrik470

Ballistic coefficient of centerfire bullets.

BC-Koeffizienten fr Bchsengeschosse.

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## kimjon

Cool, thanks for that. Quite cool having a one stop shop for BC's

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## stu#71

awesome, cheers for that.
I find it difficult to find BC's sometimes. Manufacturer's seem to concentrate on velocity and publish drop instead.
Can anyone find Federal .243 on there?

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## 303Guy

Try JBM - Calculations - Trajectory.  You might have to sign up but it is well worth it.  On the Trajectory page you can click on 'links' above the BC entry which will take you to a list of bullet manufacturer websites and there are all the bullet BC's.  The problem with Federal is they don't make there own bullets - not all of them anyway. Or simply select the bullet of choice from the pull down list and enter velocity and other data required and the software will generate a printable bullet drop and windage table.  I don't know if this software takes into account the changing BC with change of velocity.

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## Beavis

Doesn't work for me. Don't Federal use Speer bullets?

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## MattyP

Yeah what's the deal with changing BC's and where would I find the info on that for a particular projectile?

I'm wanting to order my CDS for my VX-6, but am hesitant just knowing that basic "BC" number and velocity. Even if they're slightly off then 500 on the dial might mean 550 or 450 won't it?

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## Norway

No they have to be quite a lot off on bc for that. With a good V0 figure, minor bc error will not be noticed.

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## MattyP

Thanks Norway, that's reassuring. So all they need is muzzle velocity and basic BC and the CDS will be accurate to what range you reckon? Id like to be able to take long shots at hares/rabbits.

Do you think I should shoot some paper at 200, 300, 400yds etc and send them that info? Will they even accept it since they only want those other 2 pieces of data?

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## veitnamcam

> Thanks Norway, that's reassuring. So all they need is muzzle velocity and basic BC and the CDS will be accurate to what range you reckon? Id like to be able to take long shots at hares/rabbits.
> 
> Do you think I should shoot some paper at 200, 300, 400yds etc and send them that info? Will they even accept it since they only want those other 2 pieces of data?


May i suggest you get one with just plain old moa markings. Then you are not stuck with one load at one elevation.

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## MattyP

Yeah, a good suggestion. But then how does that work? It has 1/4 MOA already - does it just label it in terms of 2, 4, 6, 8, 10 MOA, etc, so that you don't have to count clicks? Then if you change load you just re-zero and then click it back on at 0 MOA again?

I could always order both, only $50 each I think.

The appeal of the yardage one is that I would only need to use rangefinder, dial, boom. Instead of rangefinder, ballistics app, dial, boom. I am really happy with the factory ammo I am using, it shoots really great.

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## veitnamcam

Yea but its bigger than what's under the cap and is easily seen from shooting position.

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## gimp

Work out your ballistics, get a paint marker, write "2" "3" "4" "5" on your current moa-marked turret for your ranges, and you can fudge the distances between them pretty easily

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## gimp

oh wait, do you have decently usable turrets currently or the really shitty ones that came on VX3 where you can't really reset them properly? I haven't played with a VX6

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## MattyP

> oh wait, do you have decently usable turrets currently or the really shitty ones that came on VX3 where you can't really reset them properly? I haven't played with a VX6


Well, it's hard for me to tell really, having never used "good turrets." I've seen a few people complaining about VX-6's that don't click. Well, these do click, but you feel it more than hear it. I saw someone say that if you wind them up or down about 50 times then they feel much better, can't remember who.

As for if they reset properly, how do you mean? As in, dial up 10 clicks, then back down 10 clicks and see if you're still zero'd? 

I haven't really tried that as I haven't been dialing - i've just being zeroing for 200yds and using the holdovers on my reticle. Which, according to Strelok, line up perfectly at 300, 400, 450, 500 yards at 15x zoom for my load. And I am happy using those holdovers. But, I have the opportunity next R&R for some very long range hare shooting. So for anything over 500 I am going to have to dial if I still want decent zoom. Hence all the questions  :Have A Nice Day: .

Edit - many apologies for completely hijacking this thread.

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## gimp

Take a pic of the turrets? I mean reset as in, able to set them to a zero mark that is clearly visible and that doesn't move. The VX3 turrets have a stupid little ring that you rotate to set the zero mark, but it's non-locking and moves and is poorly marked.

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## veitnamcam

> Take a pic of the turrets? I mean reset as in, able to set them to a zero mark that is clearly visible and that doesn't move. The VX3 turrets have a stupid little ring that you rotate to set the zero mark, but it's non-locking and moves and is poorly marked.


The 6s ones pop up and move around to a fixed zero marker.

The cds turret is similar to the 3s but much larger and easyer to read.

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## veitnamcam



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## MattyP

Is that CDS on a VX-6, VC? Looks much smaller than I imagined, which is good.

And yeah, pretty easy to set the standard VX-6 ones at zero, although can be a bit fidgety when pushing them back down to lock them in - can end up 1 click either side.

Any point getting CDS for windage? Maybe MOA one? I have no clue about wind other than what my ballistics app tells me  :Have A Nice Day: . Decent at judging wind speeds due to working in marine environment and around cranes, etc, but haven't shot in the wind enough.

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## Norway

I  might have missed something readi g this by phone.
A G1 bc  change of 0.3 (huge error!) will only change impact two clicks at the range you indicate.

There's already perfect advice given in this thread. To sum them up cohesively:
Leave the MOA markings.
Get help calculating a trajectory.
Check trajectory with live fire.
If happy with results, mark turrets w white marker.
If that works for you, take the requested data from your table and order  nicely done turret.

And buy the DVD Greg is selling under the terminator products banner here  :Grin:

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## Norway

That DVD will import your wind skill to shooting

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## veitnamcam

Yep that's on a 6.
As you can see i didn't bother with a windage one.
Mainly because Im not confident enough to call wind accurately over distance so if its anymore than "i think i will hold on the left third of the vitals"type wind i will get closer or leave it for another day.
The small amount of gong shooting i do its not a problem to remove the cap.

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## MattyP

> I  might have missed something readi g this by phone.
> A G1 bc  change of 0.3 (huge error!) will only change impact two clicks at the range you indicate.
> 
> There's already perfect advice given in this thread. To sum them up cohesively:
> Leave the MOA markings.
> Get help calculating a trajectory.
> Check trajectory with live fire.
> If happy with results, mark turrets w white marker.
> If that works for you, take the requested data from your table and order  nicely done turret.
> ...


Yes, and I am taking that advice. And then I asked a separate question about peoples opinion on a CDS for windage as well. Not sure why you felt the need to summarize for me.

My biggest problem will be finding somewhere I can shoot long range at to check the trajectory. The range I use only goes to 100m. I will sort something.

I will definitely look into that DVD - thanks.

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## gimp

The factory windage dial looks like the VX3 style ones, ie, awful?? hard to tell. If you don't have a marked reticle for windage, get a usable windage dial

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## veitnamcam

> The factory windage dial looks like the VX3 style ones, ie, awful?? hard to tell. If you don't have a marked reticle for windage, get a usable windage dial


Yea they are pretty standard under cap stuff and i guess if talking proper turrets then yea horrible, but at least they are resetable unlike the vx3 ones.

If you do get one for windage be sure to get it marked left and right and 0 to 10 each way not 0 to 20 all round like elevation because it will Piss you off.

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## jakewire

So that Cd Dial VC, is the 1-19 in yards IE.is 1= 100 yrds, I've never had any experiece with them?

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## gimp

> So that Cd Dial VC, is the 1-19 in yards IE.is 1= 100 yrds, I've never had any experiece with them?


moa

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## jakewire

Ta.

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## veitnamcam

As gimp said mine is moa 
But the custom bit of the custom drop system (CDS) is that you can supply them with your load data and have a turret engraved in yards or meters to suit your individual load.(at a fixed average atmosphere and alt presumably)

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## jakewire

Cheers
So, just let me get this right
You supply them with the data, eg speed, bullet and bc, then they do the dial

Then what happens if say [ my chrony  :Have A Nice Day: ] the speed is not good the dial will be out. Yes?
Therefore, unlike the general target turrets, say M1 or whatever. Is it simply a matter of verifiying at range and adjusting your dial to suit then recording the difference so you know.

If the above is correct [ or if I'm miles away then tell me] then it seems to me there are too many variables to really rely on a custom Cd turret, eg ,hight speed, BC 
Because winter ,summer, powder type. If ever you wished to change anything you'd need a new CD turret, whereas with dials all you'd need to change is the Zero setting, then your up.

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## gimp

It's just a matter of having solid data before you order it, and not changing your load

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## Toby

A normal turret seems more logical

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## gimp

> A normal turret seems more logical


If you do it right, then a BDC turret makes perfect sense, it's very fast

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## jakewire

Why is it faster than winding on moa or mil from a  normal turret

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## gimp

> Why is it faster than winding on moa from a normal turret


Because there is no mucking around digging up a chart, finding the correct data etc. From position behind rifle, look at turret, turn to correct value, fire. It's also more intuitive/visual to "fudge" values between ranges.

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## jakewire

> Because there is no mucking around digging up a chart, finding the correct data etc. From position behind rifle, look at turret, turn to correct value, fire. It's also more intuitive/visual to "fudge" values between ranges.


Value would be range, would it? or Moa?
So how do you find correct moa setting  without charts and range finder

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## gimp

Range, yes

you don't need chart, just range, dial, shoot

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## jakewire

ahh simpliciy itself
No doubt you will have them on all your rifles then.

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## gimp

trick question, I only have one rifle


I haven't proved my new load well enough yet to make a BDC turret for it

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## MattyP

That's what appeals to me about yardage ones. To be honest, i'll pay 50 bucks just for a shot at it being accurate. Will get a MOA one also in case it's not so accurate.

Not having to pull out the phone and fuck around would be so much faster. 

What worries me more than anything though is all the talk I see such as, "Clicks with xxx scope aren't 1/4 MOA, more like 1/3 MOA or 1/5 MOA." That shit scares me bad. How do people test it to such accuracy? I had assumed if you pay a couple grand for a scope then the fucking clicks would be what they say they are.

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## veitnamcam

Yea the Cds would in theory be perfect for my hunting but i run two loads, tho in saying that i haven't fired an amax in probably a year.:rolleyes: :Grin:

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## veitnamcam

Matty Im sure your click values will be close enough for you not to notice. You will probably get more variation from whatever crhony you used.

You could mark out moa lines on a big bit of paper clamp the rifle and wind up and down. Remembering moa is not exactly an inch at 100y.
Or shoot at range on a windles day to verify drops and adjust velocity in app till they match which is probably all that matters(that you hit what your aiming at)

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## BRADS

> Matty Im sure your click values will be close enough for you not to notice. You will probably get more variation from whatever crhony you used.
> 
> You could mark out moa lines on a big bit of paper clamp the rifle and wind up and down. Remembering moa is not exactly an inch at 100y.
> *Or shoot at range on a windles day to verify drops and adjust velocity in app till they match which is probably all that matters(that you hit what your aiming at)*




This is the way two do it.

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## MattyP

I was actually thinking of doing that! I know that the 2699 avg velocity I got after about 20 chrony'd shots is really close. But I suspect it's actually slightly faster due to some slight differences in what Strelok tells me, and me generally hitting slightly higher. That would make sense too, since Strelok works off muzzle velocity and the chrony was a few yards away.

Another question - Strelok tells me that to change my zero from 100 yards to 200 yards is 6.2 clicks. But then to change back from 200 yards to 100 yards is 7.2 clicks. What's going on here, as one is obviously wrong? Might be a glitch in the code and I should email the developer with my load info?

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## veitnamcam

That's beyond me ? :Grin:

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## gimp

Use JBM

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## Nibblet

If you're trying to snipe anything past 300 wouldn't you be looking for the most accurate adjustment possible? So your range finder plus ballistic app with current weather and altitiude? Especially if your shooting a small rabbit at 500m +? Not a lot of room for error. 

I'm a fan of bdc reticle like on my ar but at longer range (500+) prefer dialup. Having said that I have never used the cds turrets.

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## MattyP

Yeah, that's a good point. A yardage CDS I am interested in more for shots on larger animals where time might be a major factor.

Small targets like rabbits/hares you have all the time in the world from decent range, and you're right - I would be using ballistics programs, etc.

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## Norway

No need for app in the field.
Get the yardage CDS you want.
Make a swedish method scheme referenced to your CDS and you'll shoot faster.

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## Nibblet

I'm going to have to pull finger and log shots at different ranges then maybe just 'paint' on my turrets. See how that works out. 
App is pretty close so should be able to just tweek it and go off the readouts on that?

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## Norway

This is all shown in the coming film but:
Shoot 2-3 distances.
Match ballistic software trajectory to that within 2-3 clicks.
You're done. Trajectory will be perfect.
Change one variable to explore the effect of changing weather. 
Use V0 change 0.5 msec per 1°C unless you have other data.

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## Nibblet

Cheers Norway, will do that tomorrow morning.

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## MattyP

> No need for app in the field.
> Get the yardage CDS you want.
> Make a swedish method scheme referenced to your CDS and you'll shoot faster.


What is a swedish method scheme?

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## Norway

I think Gimp is better situated to assist here, I'm on a mobile.

It is basically a practical ballistic chart tuned to your environment and BDC.

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