I often notice that some shooters run scopes and a RDS or even the ACOG with RDS. What are your zeroes for the scope and RDS? Are both zeroed at 50yds? Or maybe the scope is at 100 and RDS at 50? Thanks.
For a scope with target turrets, I zero at 100 and slip the rings to 100 if I have a BDC. Any optic I have that doesn’t have adjustable turrets, or some kind of range compensating reticle, gets zeroed @ 50.
The ACOG with Mini Red Dot (ACOG MRD) models recommend zeroing the MRD at 40 meters, and the ACOG at 100 meters with 62grain round.
I have mine zeroed for 50 yards, and there’s some slight hold-over for closer ranges.
Pretty much all ACOGs are to be zeroed at 100 meters, which allows the BDC to work. Most magnified optics are best setup with a 100 meter zero as the base-line, or at least those applicable to the AR as a fighting platform.
While other options exist and are usable, a 100 yard/meter zero with an RDS is very effective, especially at close range, due to the decreased offset differences at those ranges. It is easily arguable that the 100 yard/meter zero is actually the best zero for most applications that an RDS is applicable for.
In the spirit of simplicity and efficiency I zero everything at 100 meters now. That means that there is no difference in application/hold-over between my guns with a TA11G, TA11JG, M3 w/ 3X, T1, NF 2.5-10X, or DMS. My offset MRDs are also on a 100 meter zero. There is a little bit of difference between an offset MRD and a piggy-backed MRD (both with a 100 meter zero) as far as close-range hold-over is concerned, though it is not excessive (less than the difference between a 50 yard zero and a 100 yard zero) it should be trained with extensively if you decide to go against the recommendation to avoid piggy-backed MRDs or are forced to employ it in that manner.
I have significant experience with a 300 yard zero, 50/200 yard zero, and 100 yard zero. Even with non-BDC optics I find the 100 and 200 yard/meter zeroes to be the easiest to use rapidly under stress across the spectrum of my employment needs. If multiple similar employment optics exist in the inventory it is more efficient to zero them all the same.
IMPORTANT NOTE- This assumes a zero at actual distance; 100, 200 or 300 yards/meters, NOT an expedient zero at closer range. Zeroing a piggy-backed MRD at 50 meters will not give the same trajectory as a 200 meter zero since the sighting plane is significantly higher than normal.