Hi, I've joined this forum because I need some advice with BDC reticles:

I've got the Minox ZA 3 BDC scope on a Tikka T3 270, using Winchester Super X 130gr. I'm struggling to find information regarding the .270's bullet drop in-relation to the Minox's BDC lines. The manual that came with the scope had no such info.

I'm wanting to confidently shoot between the 100-400yard range, and eventually back myself for the 500yard shots. I currently have the sight zeroed at 100 yards.

I'm a steady shot, but just need more information to help place my shots at longer distances better. Any information, or direction to relevant info would be greatly appreciated.

Thanks

I don't know the Minox BDC reticle at all,and possibly someone who knows will comment.

But absent that, if I were doing it, I would zero 2" high with the center reticle,then back off to 300-400 yards and see how your point of impact relates to the other lines of the reticle.

You can read about it, but it would always be best to confirm POI by actual shooting whenever possible. I can't see it taking any more than a couple of range sessions to get the answers you want.

BTW, welcome to the CF.

I spoke with my Minox tech rep and he replied:

"That�s a tough one, since he�s sighted it in at a shorter distance than what the reticle is calibrated for. Given the subtensions, it�s designed to be sighted in at 200 yards. Regardless, given his ballistics, one can give him guidance on what the correlation would be.

With him shooting a .270 Win. with Winchester Ammo 130 grain Super X Power Point bullets, his muzzle velocity would be 3,060 fps and with a ballistic coefficient of 0.372. now we�ll need to look at a ballistics calculator that will allow us to see the ballistics in 10 yard increments (www.biggameinfo.com). Given the subtensions at 100 yards for his reticle and taking the designated 300 yard mark, multiplying the subtension value at 100 yards by 3, the designated 300 yard elevation mark actually corresponds to 250 yards, whereas the 400 yard elevation mark (with a 4x calculation) actually corresponds to about 355 yards. Now if he sights it in at the designed 200 yards, then the 300 yard elevation mark corresponds to 295 (essentially 300) and the 400 yard elevation mark to 395 (essentially 400)."

O K, sight it in for 200. You will only be around 2" high at 100 and all else seems to fall in place. Best wishes, jack

Send me a PM with your email address... and I'll send you a couple of drop charts and crosshair printouts.

Assuming a generic 130 Grain .270 Flat Based Bullet (BC .425ish) at 3000fps (generic .270 Win. Load)

200 Yard Zero (=1.25"@100).... windage hash marks are 3.2 MOA (for all intents...). In a 10 mph crosswind this would be about 300 yards.


300 Yard Zero (+3.5"@100)

The best way to zero a reticle of that type is to find a 400-yd range and zero the 400-yd stadia at an actual lazered 400 yds. Your 500 and 300 yard stadia will then line up just peachy and your rifle will be nominally zeroed roughly 2" high at 100 yds.

This cuts straight to the chase and eliminates all manner of potential confusion.

Running a BDC reticle at a nominal 100-yd zero is a bad idea and will only confuse you.

According to the spec sheet, on 9X the distance from the crosshair to the first stadia line is 2.11 MOA and 4.71 to the second stadia line.

That is correct... The Windage marks are at 3.2".



Please explain how you can have a 300, 400, and 500 yard stadia lines given the above picture.

Thank you all very much, that's very helpful. I'll re-zero at 200 yards and do some tests.

Great to know there is genuine help out there, you have saved me alot of time and money.

All the best.