Looking at the EXPS2 and EXPS3, is the included 7mm riser and quick release mount required for its use? Or can you remove the QR portion and use the unit at the standard height in order to absolute co-witness?
Thank you in advance.
Looking at the EXPS2 and EXPS3, is the included 7mm riser and quick release mount required for its use?
-Yes
Or can you remove the QR portion and use the unit at the standard height in order to absolute co-witness?
-No
the XPS, not EXPS, mounts with screws at standard cowitness height.
Thanks for the fast answer. So that means, if I have read the website correctly, that there is no NV capable option with side-mounted controls and CR123 power source that does not have the 7mm rise?
Hmmm… this is really complicating my next EOTech purchase.
Been a couple days so you probably have your answer, but you are correct.
There is NO CR123 model that has NV compatibility AND side mounted buttons, WITHOUT the riser/QD
Thanks sjwolf, that seems to be the consensus. Was hoping to keep the same height as my other EOTech without putting it on a raised mount. I think I’ll just go with the EXPS3 and not sweat the riser.
I appreciate the reply.
Just purchased the EOTech EXPS3.0 HWS and G33.STS 3X Magnifier for my BCM MID 16 MOD 2 M4. When I zeroed the M4 using the BUIS I zeroed at 25 yards which was also very accurate at 100 yards. With the EOTech I am spot-on at 25 yards but found that I had to lower my aiming point at least 5 inches at 100 yards to hit the center of the target. Is this normal for a HWS? Any advice will be appreciated.
HWS isn’t any different than any other RDS relative to zeroing. At what range did you zero the Eotech?
That’s normal for a 25y zero on an AR.
It’ll be roughly +2" at 50, +6" at 100, +7" at 200, and will become POA/POI between 300-325.
As noted, I zeroed the EOTech HWS at 25 yards, the same distance as I zeroed the BUIS. I expected that the HWS would be a little more accurate without adjustment at 100 yards but given the characteristics of the M4 that may not be the case. I’ll just have to adjust as necessary at greater distances. Thanks for the feedback!
See my reply to GTF425.
You said you “zeroed the M4 using the BUIS”. Does that mean you zeroed the EoTech too, or did you just zero the BUIS and then set the red dot at the top of your front sight?
Sir,
Not trying to argue with you, but you can not zero POA/POI at 25 and maintain the exact same POA/POI at 100. Even with a max ord zero at 100, you will still have a holdover at 25.
Given AR irons are roughly 2.5" over the centerline of the bore, the trajectory of the round and our line of sight being aligned at such an extremely close distance as 25 yards is what causes such a dramatic rise in POI from 100-250 yards. It’s not a matter of sight construction, it’s the side effect of having our line of sight offset from the center of the bore and intersecting them at such a close range.
Your EOTech is doing exactly what a 25 yard zero should be doing. It’s not the problem, the 25y zero is. It’s a bullshit zero that we used as a compromise in the Army. The 50/200 is much preferred due to basically eliminating any significant POA/POI shift from 25-250 yards. Extending your zero distance also allows you to fine tune your windage, as at 25 what appears to be centered may be 2-3" off at 100.
As for the irons: without seeing you shooting and then your targets back to back, I can’t say. But having coached hundreds of Soldiers over the years with 25m zeroes, the results were always in line with what I typed above. I’m sorry I can’t help you there.
I initially zeroed the BUIS at 25 yards following the standard zeroing process using a 25 yard zeroing target. My shot group was tight at 25 yards. As expected, I had to make a POA/POI adjustment at 50 and 100 yards to hit the center of the target.
When I added the EOTech HWS, I zeroed the HWS electronically by moving the red dot to the top of the already-zeroed front sight using the windage and elevation buttons on the HWS. The proof is in the pudding as they say so I took it to the range and fine-tuned the zero with live fire. It required a couple of minor adjustments to the windage and elevation settings on the HWS but I achieved a tight group at 25 yards. I guess my expectation was that the POA/POI adjustment at 100 yards would not be as pronounced with a HWS as it was with BUIS, but in thinking it through I realized that there should not be a significant difference between the two sighting methods since the HWS zero is based on the BUIS zero by virtue of placing the red dot over the already-zeroed front site. If the BUIS sights require a 6" adjustment at 100 yards, then the HWS should require a similar adjustment. Is my logic sound?
Thank you very much for the feedback.
No argument perceived on this end. Your explanation makes perfect sense. I recall something from my military days that a M16/M4 zeroed at 25 yards would also be be zeroed at 100 yards, but given my experience with both BUIS and the HWS on my M4, that does not appear to be the case. Your very reasonable explanation sheds the proper light on it. I will re-zero at 50/200 as it seems much more appropriate for the M16/M4. Thanks very much for your constructive comments.
Yeh, couple of observations…
[ul]
[li]50 yard zero is standard for the AR15 and similar, as GTF45 said. 25 yard zero is a quick-and-dirty method that is marginally suitable in and useful mainly in situations where you don’t have 50 yards.[/li][li]zero the RDS separately from the BUIS, each on their own. Usually correlating it with the BUIS is pretty close, but machining imperfection in the sights or the RDS mount, tolerance stacking, and the significant difference in height over bore makes it also a quick-and-dirty sighting method and not reasonable to expect dead-on accuracy from the RDS.[/li][/ul]
Give it a shot, and I would recommend taking 2 full size cardboard IPSCs to the range with you. Put 4 bulls on each, and make storyboard targets to compare a 25 vs 50 yard zero. Shoot groups at 25, 50, 100, and 200 if available. It really puts in perspective how much easier it is to make accurate hits with a solid zero at 50 (or 200, preferably).
And they told us something similar when I was coming up in the Army. We were always told 25=300, which I have the targets with groups to prove it does not. Additionally, we have some excellent threads on here covering the pros and cons of varying zero distances. An example can be found here:
https://www.m4carbine.net/showthread.php?65679-AR-15-Zeros-and-Trajectories
Regardless of whatever route you go, please don’t take mine or anyone else’s word at face value. Hit the range, make the targets, and have objective proof of what will work best for you.
Also, it’s been a few months, but welcome to the forum and thanks for carrying the torch while serving.
This is a very good point as well.
Two different sighting systems. Zero them independently. And as for co witnessing full time, parallax shift exists in all optics. Make another storyboard target and see how your particular optic prints when forcing a parallax shift.