Alright, I just purchased a nice used TA31RCO for $700(friend) and although I am happy with my aimpoint I am pretty stoked to be shooting the RCO again since I haven’t played with one since I was active.
A lot of us only have access to ranges that are in yards. Which brings up the question of how to properly zero an optic (like a trijicon RCO) at a 100 yard range. I have been searching for hours and have not found a clear answer as of yet. Any help would be appreciated.
Set up a target at 109 yards with your rangefinder. Is this question as simple as it sounds?
Dude this is exactly why the question will not be answered. I have obviously found out that 100 METERS = 109 YARDS. Now, that would be very easy to do but MY RANGE IS OUT TO 100 YARDS!!! I can not just go and move the berm of this companies range or shoot 9 yards behind everyone else.
I really do not want this thread to wind up like ALL of the others regarding this subject have turned out to be, which includes people bickering and no answers being developed. I have a serious question and hope that someone could answer it for me. What would the POI be at 100 yards for a 100m zero? That might make the question easier to answer.
Tell me what rounds you are using and the barrel length and I will plug into the ballistic software and tell you where to sight in to put it on at 109 yards. Fair?
Dude, that’s perfect, thank you. It’s a 14.5" barrel using M193 ammo.
Using standard temp, pressure and altitude and 3050 fps for standard M4 and M193 BC of 0.243 I come up with POI 0.08 inches high at 100 yards will put you on at 100m. Is this what you are looking for?
Yea…in a way. It just comes down to realizing that unless you have a 100m range there is no way of actually zeroing at 100 yards. Not even the best shooters can get .08 high ya know? Answered the question for sure, thank you. Ive never had this problem since everytime I shot the RCO was during qual and the range was in meters. It is seeming like the practicality of an ACOG is low for anyone who doesn’t have access to a range in METERS. I am sure that if you zero at 100 YARDS than the POI wouldn’t change much within 300 yards and maybe out to 400 (which is more than I plan on doing). It was just eating at me that I would have this BDC that isn’t correct. I plan on using the ACOG as a hunting scope (feral hogs and deer) but I want to make sure that I can have correctly placed shots and not be all screwed up because I have a 100 yard zero and not a 100 meter zero.
Does that software have the ability to show the difference in a 100 yard zero vs 100 meter zero with same bullet and barrel?
POI will be 0.20 low at 100m if zero distance is 100 yards. That’s about as good as I can do right now.
Alright man thanks for all of your help. Ill continue my search and see if I can find a comparison of the trajectory patterns for the 100 meter vs 100 yard.
With 193 don’t worry about it. You aren’t going to kill any deer or hogs at 3-400 yards anyway! 556 was never intended to kill things at that range. Not animals that don’t know what hurt is.
Are you looking to see what the difference is at specific ranges (100 yd/m, 200 yd/m, 300 yd/m, etc…)?
Yea i hear ya! Thats why i stated that I wasn’t intending to shoot very far. I just wanted to make sure that with 55grain (SP, FMJ, ETC.) that I wasn’t going to be too far off on the BDC. I know a lot of people zero their ACOG at 100 yards and it is fine. I am assuming that within 200 yards the difference in trajectory will not even be noticeable unless you are a sub MOa shooter and same probably applies to the further distances. I was just obsessing over it because I get like that sometimes, but feel a lot better now.
I sighted my TA31RCO (chevron) in at 100 yards and have shot coyotes at 300 yards several times using bdc. Great optic for that range. I don’t shoot past 300 with that setup and reticle.
Yes that is exactly what my next step was going to be!! That would help me understand my trajectory after I zero at 100 yards.
I do not plan on going past 300 either. The only time I shot past 300 yards in my life was during the range qual. Good to know that you zero’d at 100 yards and were effective out to 300. I kind of figured that the trajectory difference in range/yards couldn’t be outside of + or - 5 inches.
Zero at 100 yards will put you -12.98 inches at 300 yards and -17.07 inches at 300m (328 yds).
The POI delta between 100yd and 109yd is going to be less than a click, so I wouldn’t be concerned about that.
For ACOGs and similar BDC setups, it is possible to start off with a zero for 300m on the tree at 36yd - it’s not great, but it gets you close very quickly.
I get that the range stops at 100 yds., but if there’s a chance you could put up a target at about 23 yds., do you think these would help?
https://www.m4carbine.net/showthread.php?95226-Improved-AR15A2-A3-A4-amp-AR15-Carbine-Zero-Targets-50-200M-100M-amp-300M-Zeroes