BDC scopes

[mortman]

Hello,
Looking at various BDC scopes, Nikon looks good. Cabelas even has one under their brand name for under $200. But I guess I am missing something here. Shouldn't a bullet drop compensating scope be caliber specific, at least, if not bullet weight specific.

I aint no physics major, so maybe I just don't get it.

Anybody who can help me out here?

Thanks,
M.

[brando]

Yup, they are caliber and load specific. For example, I think the BDC on a particular version of the Leupold Mk4 was set to FGMM .308. Some of the newer high end scopes have swappable BDC cams like S&B's Short Dot, where you can switch between loads like Hornady's 75gr TAP or Mk262. US Optics is such a good, custom scope manufacturer, they'll laser engrave a BDC for you if you send them the ballistic tables on your load.

So yes, they are load specific, thereby somewhat limiting its use. This is why most folks who use a precision rifle tend to lean more towards reticle holdovers than dialing in a BDC as you can calibrate it for whatever load you want.

[4 Brigada]

As brando posted they are caliber and load specific. But up to a point, they work with a specific ballistics curve, so if you can match the caliber/load to match or come as close as posible. Then you can tweek the scope to maintain the point of aim to point of impact relation. Example the SUIT sight has a cam for 7.62 and one for 5.56 there is very little difference up to 200 meters ( human size target) between one and the other. I have a NIMROD , made for the 7.62 M118 or clone thats what I use. I can use other loads and tweek it , I tested it. Funny I didnt know jack on how to do any of this learned it on a sunday afternoon at the range for a guy.

[ar15barrels]

BDC knobs are also weather specific.
The BDC knobs will get you close as long as the ammo is correct, but it will never be spot-on unless you are in the "standard" weather conditions for which the BDC knob was designed.

In the end, you are better off learning your drops in all conditions at all the ranges you shoot at and using your aquired drop data.

[jtv3062]

On the Nikons, they have circles in the vertical post of the cross hair, you have to figure out what range those circles represent. For an example you zero at 100 yards the first do would be 138 yards second 173 and so on.

The mark 4 m3 has cams for the 223rem 55 gr, 308 win 168 gr, 30-06 180 gr, 300 win mag190 gr.

[ar15barrels]

On the Nikons, they have circles in the vertical post of the cross hair, you have to figure out what range those circles represent. For an example you zero at 100 yards the first do would be 138 yards second 173 and so on.

Are you talking about a mil-dot reticle?

[elSquid]

Are you talking about a mil-dot reticle?

Nikon BDC:



-- Michael

[jtv3062]

Are you talking about a mil-dot reticle?

what elSquid posted

[pat4wd]

the BDC is just a ballpark.. Kinda misleading really.. you need to know your gun and ammo, You need to shoot and see where you end up.. Barrel length also is a factor.. Just this last weekend I was out seeing where my loads out of my rifle were hitting at differant yardages.. so the BDC's are nice but it is up to you to know where and how far

[Scold]

Do some research on the Zeiss Rapid Z Reticle. It's pretty damn impressive.
You can calibrate it for the specific load you are shooting.

http://www.zeiss.com/c1256bcf0020be5f/Contents-Frame/3dc0003746ab21148525726200057786