Zeroing in yards, BDC is in meters?

[TBomb]

Hey guys, I have a question about zeroing and the effect on a BDC. The range I have access to has its target areas staggered in yards (50/100/200) but the BDC reticle for the optic is designed around meters. Will zeroing at 100 yards when the BDC is designed to be zeroed at 100 meters cause the BDC to be off by a large margin? It's a difference of about 9 yards at 100 meters, but almost 30 at 300. Also, if I'm shooting M193 out of a 16" barrel instead of the M855 out of a 14.5" barrel that the BDC is calibrated for will that make a big difference as well? I would like to be zeroed so that the BDC will be as accurate as possible, but that might be difficult to do without shooting the same ammo the BDC was designed for. Thanks!

[Failure2Stop]

Best way- zero and shoot at distance. You really need to do this anyway even if you have a properly zeroed optic, as the BDCs are really just compromises and educated guesses with generic ammo performance.

Option 2- Employ the links below to give you an accurate estimate prior to confirming at distance.
Metric Conversion
Ballistic Calculator

You will nver know how far off you will be with your gun, with your ammo, at your range, etc. etc. without confirming the BDC at actual known distances. If you do not have access to those distances, the calculator will give you a pretty good idea.

[TBomb]

Best way- zero and shoot at distance. You really need to do this anyway even if you have a properly zeroed optic, as the BDCs are really just compromises and educated guesses with generic ammo performance.

Option 2- Employ the links below to give you an accurate estimate prior to confirming at distance.
Metric ConversionBallistic Calculator

You will nver know how far off you will be with your gun, with your ammo, at your range, etc. etc. without confirming the BDC at actual known distances. If you do not have access to those distances, the calculator will give you a pretty good idea.

Ok, so here's my plan for now:

Zeroing at 100 meters (~110 yards) would equal about .1" high at 100 yards. At 200 yards it would be 2.8" low. I am planning on zeroing at 100 yards and then shooting at 200 yards using the 100m "zero" reticle. If the group is decently sized and within 2.5-3" low at 200 yards and the POA with the 200m mark on the BDC is pretty close to POI then I think I'll be happy. How does this sound?

[Charles]

The difference in bullet trajectory from 70 to just over a hundred yards is less then a tenth of an inch. "Zero" at 100yds, you'll be "zeroed" at 100 meters.

[2-BPM]

i wondered the same thing when i put a usmc rco m4 on my civie m4 with 16" barrel, so i did this test: i zeroed the ar at 100meters, and set up a target with a bunch of 2" dots on index cards. i shot my zero with lake city M855 62 grain, and went on to shoot 55g wolf, 62g ss109 british, 75g Prvi partisan match, 77g blackhills, and 55g american eagle. 3 shots per target, all stayed in the black. so i repeated this at 200, 300, 400 and 500 meters. all rounds stayed on target. ( center mass of a IPSC target) i was happily surprised with my informal test. 77grain black hills is my COMWEC round, but i shoot 55grain whatever is on sale for 80% of my personal training. i shoot both without any concern of the bdc. so yeah, the bdc is close enough to not really matter on man sized targets try the`same with various loads, and you'll have peace of mind.