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Posted: 2/14/2017 2:18:48 PM EDT
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Hi guys,
BLUF: I am zeroing a rifle at 25 meters, using the US Army "25 METER ZERO TARGET M4 CARBINE (NSN 6920-01-395-2949)," an approximate M4 clone, LC XM855 and an issued M16A4/M4 carry handle. Should I zero the rifle with the point of impact center mass within the four centimeter circle on the target? Or should I adopt the dropped BUIS offset as described on page F9 of FM 3-22.9? For detailed background on this question: I'm not in the Army anymore but my wife still is. She's finally wanting to get serious about her annual rifle qualification and has asked for my help. Her stipulation: everything has to closely mimic the way it will be for her army rifle qual, which is consistent/logical given her goal. So please, no advice about why a 25 meter zero is a bad idea. I get it, she gets it, we all get it, but it's irrelevant to this discussion. She doesn't want to memorize one set of holds for her personal rifle (wifle?) and a different set of holds for her issued weapon. In discussing specifics with her, there arose an issue: Her non-combat arms unit generally treats rifle quals as an afterthought and, as such, they do the bare minimum to get it done. This means issuing out rifles with the matech back-up iron sights and using them exclusively for their zero and qualification tables. To my knowledge they don't even bother taking optics out of the arms room in that particular portion of her unit. I have a lot of heartburn over this, as to my mind the matech was never intended as a primary sight, only as a backup to an optic. My solution to this problem: for consistency's sake both her issued and personal rifles got milspec carry handles. Problem solved, but a new one then arose: When dusting off my 25 meter zero knowledge, FM 3-22.9 goes to great lengths to describe zero for BUIS (matech), CCO, ACOG, etc. As per the FM each of these call for a modified zero offset procedure which is specific to the sight being used. But unless I am missing it somewhere, it doesn't SPECIFICALLY address the carry handle. It just says: "Ensure that the correct 25-meter zero target is being used. For M16A1s, use NSN 6920-01-167-1392 (Figure 5-18); for M16A2s, M16A3s, M16A4s, M4s, and M4As, use NSN 6920-01-395-2949 (Figure 5-19; M16A2/A3 is printed on one side, and M16A4/M4/M4A is printed on the other)." Now, to my mind, the implication of the manual is that standard zeroing is done with a carry handle. I can't find where it says that outright, but I that is my assumption. The instructional adjustment markings on the target are for iron sights. Furthermore, previously in the manual it calls for the shooter to place the rounds in the four centimeter center mass circle. Later, it DOES call for a down-elevation zero offset for the BUIS/matech but I am skeptical that this would apply to the carry handle also. So unless you guys tell me otherwise, I am going to coach her to zero center-mass of the target circle. It is also my understanding that the "Z" rear elevation setting is for the M16A4 and not the M4, which stays bottomed out on the 8/3 setting. She's going to have to be in charge of her own zero; from my experience the non-combat arms E4s who will be the range safeties/coaches are unlikely to have ever cracked the FM on this. In fact, my bet is that they will actually incorrectly zero ALL iron sights center-mass of the target, failing to account for the prescribed offset for the matechs. I've seen it in other units before, where the OIC/NCOIC generally assume that the POI is always center mass which is incorrect as per the FM. BUT in case she gets a safety who coaches her to down-offset the carry handle POI too, I want to be sure I am steering her in the right direction by insisting that she zero for center of mass POI. For verification of my suppositions, I submit this question to the SMEs on ARFCOM. Thanks in advance, and I apologize if I missed anything. |
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I didn't read your wall of text. Â It would seem you are over-complicating this.Â
The bottom of the target should have instructions.  1. Set rear sight to one click past the 8/3 setting 2. Aim at target center and adjust sights to bring shot groups as close as possible to the center of the circle. Adjust front sight elevation only. 3. Set rear sight elevation back to 8/3 setting. Weapon will be zeroed for 300M. The target also says which way to turn each sight. Essentially, at 25M, point of aim should be point of impact with the recommended sight setting.  Same with 300M with appropriate setting. Google up the target.  There is a nice .pdf of it you can print and use.  No need for any NSN or official target. |
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Hi wildearp,
Thanks for your reply. I have the targets and know what is printed on them. Also, FYSA you may be reading the wrong target when you googled it. The M4 carbine zero target actually says to zero it on the 6/3 setting then leave it there. I have a PP presentation from the maneuver center which states the same. But I understand it's confusing, with the Army producing multiple zero targets for different rifles and then issuing user nods in the FM to further delineate POA/POI for different sights. Hence my request for clarification. Thanks again. |
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Here is what I suggest. It might not be the best option for you.
I have used the 6/3 (small gap, small aperture) setting with a 14.5 inch barrel firing M855 at 25 meters. That put my group on the center of a 18 inch bulls eye at 300 yards. (I know 300 yards isn't 300m, but that is what I shot). So, I would suggest if she is using the carry handle that she leave it on 6/3. |
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Quoted:
Here is what I suggest. It might not be the best option for you. I have used the 6/3 (small gap, small aperture) setting with a 14.5 inch barrel firing M855 at 25 meters. That put my group on the center of a 18 inch bulls eye at 300 yards. (I know 300 yards isn't 300m, but that is what I shot). So, I would suggest if she is using the carry handle that she leave it on 6/3. Yeah 10-4, that was already my plan on the zero knob unless someone definititively stated otherwise. My question is really whether or not I need to apply the down-offset prescribed in the field manual for the BUIS to thecarry handle, or keep POI center mass. I am pretty sure it's center mass but am picking the brains here in case I am wrong. You would need to have a basic familiarity with FM 3-32.9 to really understand my question. So fellow Army nerds, jump on in. For those of you unfamilar let me clarify: To zero certain site systems the army prescribes POA center mass but POI a set number of centimeters down. The FM details such an offset for the matech BUIS on the M4. My question is if that down-offset should be applied to the carry handle, as they are both iron sights. I don't think it is, but wanted to be doubly sure. I currently only have access to 200 yards for firing, so I can't test its full application in real life to test it. |
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Quoted:
Here is what I suggest. It might not be the best option for you. I have used the 6/3 (small gap, small aperture) setting with a 14.5 inch barrel firing M855 at 25 meters. That put my group on the center of a 18 inch bulls eye at 300 yards. (I know 300 yards isn't 300m, but that is what I shot). So, I would suggest if she is using the carry handle that she leave it on 6/3. BUUUUT, I suppose your response does seem to verify that POA/POI at 25 meters does generally equate to POA/POI at 300 meters given 14.5" 1/7 twist barrel and M855. So thank you and I appreciate that data. Seems to support my supposition. |
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If they are both iron, and both zeroed at 25 yards, you will have the same hold under in inches for both at the varying distances until you reach 300. The problem arises however that no two rifles will shoot exactly the same. For 25-300 however it should be close enough for government work, provided the rifle you built is a close match, and the one she is issued hasn't been shot to shit. This will effect the 300 hits greatly, even though technically and on paper it should be spot on with the 25.
ETA the hold under only applies if she makes no elevation changes to the rear sight, which seemed like was your goal. |
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Have her aim at center of mass of the zero silhouette.
She wants her bullets to group in the lower half of the golfball-size circle in the silhouette. She should be zeroed for center-of-mass at 200 yards. If she aims at the chin of the 300-yard and 300-Meter silhouette she'll impact center-of-mass. To prove it to yourselves shoot a 10-shot group on an E-type on a Known-Distance range so that you are 100% convinced. Best to both see it and believe it, then kill it. This is a view of the KD qual range with shooters at the 200 yard line (they shot at 300, advanced to 200, and are getting ready to advance to the 100 to shoot on a knee -- E-type silhouettes on the left, F-type on the right): 
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