Here is my attempt to gather all the information on MP5 Red Dots and Mounts. I have threatened to make a one-stop thread and here I am! Since I got the MP5 bug I found myself searching for this info. Then once I had a few mounts/optics under my belt I would comment here on Pro or Arfcom. The same questions always seem to come up so maybe we can get them all answered here.
The AR platform has a standard of absolute co-witness and 1/3 co-witness. There is no such standard with the MP5 but I will try to relate my findings to these standards.
Absolute co-witness means that if you are perfectly aligned with your optic, the irons are also lined up in the center of the optic. Any other setup, means the irons are either above or below the red dot, or not in the view at all.
If the irons can still be seen through the optic, you can get a co-witness when you go off axis on the red dot and use manufacturers' "parallax free" ability. I use parenthesis because it has been shown that most, if not all, red dots have parallax the further you get from the center of the optic. Green Eye Tactical did some good work on this topic:
https://www.greeneyetactical.com/2017/07/27/comparative-study-of-red-dot-sight-parallax/
I do not have the height of the basic iron above bore numbers for the MP5. I gathered data from manufacturers where I could with respect to optical height for their mounts and these are the numbers I discuss below.
My own MP5 experience is this: I own a Z-5P (MP5K-PDW) that came with an optic rail. I have owned the B&T 10266 & 21241 and the MFI Low Mount. EDIT: I have a full-size AT94P now as well. But of course, this all applies to both models. On the full-size, I am using the 21241 and Holosun micro.
Absolute Co-Witness
Battle Steel direct mount. This looks really low and could be absolute co-witness. I have never seen one in real life but I did test the MRO mount further down this post. Confirmed by user Dragnet, this is absolute co-witness:
(image unavailable)
RMR direct mount to rear sight. This option replaces the rear sight with a mount designed for the RMR. Yup, this can't be called co-witness since there is no rear sight. How about: this is "absolute co-witness" height.
Pics from Oicani.
![Image]()
![Image]()
How to get close to 1/3 Co-Witness
The lowest MP5 adapter rails I know about are the B&T 10266 (short) and the B&T 21241 (long). MFI has something called the Ultra Low and I believe these are as low as the B&T. I also believe the welded-on rails are about the same height as these rails but cannot confirm that.
Mount/Optic Combo
Aimpoint Micro factory H1/T1 mount, non-QD - 18mm (~0.71") optical height
+
Aimpoint Micro H1/T1 or clones like the Holosun/PA.
=
~1/3 Co-Witness, I suppose the red dot is about halfway between the front sight and the bottom of the front sight hood.
NOTE: You can buy a QD upgrade/latch for those mounts. Botach sells a kit as well.
B&T 21241 + Holosun + Aimpoint Low Mount (non-QD)
The dot is closer to the hood if you use the Aimpoint LRP QD without a spacer. This mount is rated at 20mm which is 2mm higher than the original low mount. It makes a difference! I have one of these and learned the hard way that it was higher than the non-QD.
Next up are the Aimpoint 30mm Optics with a Low Ring (21mm optical height per Vortex and Aimpoint). This is pretty close to the hood and I can see why guys cut off the hood with these setups.
Shown below is the PA 30mm Clone in a Vortex Low Ring:
From user CZ-75:
![Image]()
![Image]()
A new option: the direct mounts from Battle Steel (aka Botach). This MRO on the direct mount is about the same height as the 30mm Optic and Low Ring above.
Shown below is the PA 30mm Clone in a Vortex Low Ring BUT with the Zenith Rail, which put the dot above and clear of the sight hood. Very usable with decent cheek weld. NO co-witness as shown below.
EDIT: I removed my conclusions. Leaving this thread purely just information.
MRO on Trijicon factory low mount 25mm or 0.985" optical height.
On the low rails 10266/21241 this puts the dot on the hood. On the supplied Zenith Rail, which I think is the same height as the SP5K rail, the dot clears the hood. I used this initially and it worked great.
More to follow:
- Fast Fire 3 on supplied low mount. No numbers and I remember the dot on the hood with the low rails.
/moderator edit:
See also this thread for further pictures:
www.hkpro.com
The AR platform has a standard of absolute co-witness and 1/3 co-witness. There is no such standard with the MP5 but I will try to relate my findings to these standards.
Absolute co-witness means that if you are perfectly aligned with your optic, the irons are also lined up in the center of the optic. Any other setup, means the irons are either above or below the red dot, or not in the view at all.
If the irons can still be seen through the optic, you can get a co-witness when you go off axis on the red dot and use manufacturers' "parallax free" ability. I use parenthesis because it has been shown that most, if not all, red dots have parallax the further you get from the center of the optic. Green Eye Tactical did some good work on this topic:
https://www.greeneyetactical.com/2017/07/27/comparative-study-of-red-dot-sight-parallax/
I do not have the height of the basic iron above bore numbers for the MP5. I gathered data from manufacturers where I could with respect to optical height for their mounts and these are the numbers I discuss below.
My own MP5 experience is this: I own a Z-5P (MP5K-PDW) that came with an optic rail. I have owned the B&T 10266 & 21241 and the MFI Low Mount. EDIT: I have a full-size AT94P now as well. But of course, this all applies to both models. On the full-size, I am using the 21241 and Holosun micro.
Absolute Co-Witness
Battle Steel direct mount. This looks really low and could be absolute co-witness. I have never seen one in real life but I did test the MRO mount further down this post. Confirmed by user Dragnet, this is absolute co-witness:
(image unavailable)
RMR direct mount to rear sight. This option replaces the rear sight with a mount designed for the RMR. Yup, this can't be called co-witness since there is no rear sight. How about: this is "absolute co-witness" height.
Pics from Oicani.
How to get close to 1/3 Co-Witness
The lowest MP5 adapter rails I know about are the B&T 10266 (short) and the B&T 21241 (long). MFI has something called the Ultra Low and I believe these are as low as the B&T. I also believe the welded-on rails are about the same height as these rails but cannot confirm that.
Mount/Optic Combo
Aimpoint Micro factory H1/T1 mount, non-QD - 18mm (~0.71") optical height
+
Aimpoint Micro H1/T1 or clones like the Holosun/PA.
=
~1/3 Co-Witness, I suppose the red dot is about halfway between the front sight and the bottom of the front sight hood.
NOTE: You can buy a QD upgrade/latch for those mounts. Botach sells a kit as well.
B&T 21241 + Holosun + Aimpoint Low Mount (non-QD)
The dot is closer to the hood if you use the Aimpoint LRP QD without a spacer. This mount is rated at 20mm which is 2mm higher than the original low mount. It makes a difference! I have one of these and learned the hard way that it was higher than the non-QD.
Next up are the Aimpoint 30mm Optics with a Low Ring (21mm optical height per Vortex and Aimpoint). This is pretty close to the hood and I can see why guys cut off the hood with these setups.
Shown below is the PA 30mm Clone in a Vortex Low Ring:
From user CZ-75:
A new option: the direct mounts from Battle Steel (aka Botach). This MRO on the direct mount is about the same height as the 30mm Optic and Low Ring above.
Shown below is the PA 30mm Clone in a Vortex Low Ring BUT with the Zenith Rail, which put the dot above and clear of the sight hood. Very usable with decent cheek weld. NO co-witness as shown below.
EDIT: I removed my conclusions. Leaving this thread purely just information.
MRO on Trijicon factory low mount 25mm or 0.985" optical height.
On the low rails 10266/21241 this puts the dot on the hood. On the supplied Zenith Rail, which I think is the same height as the SP5K rail, the dot clears the hood. I used this initially and it worked great.
More to follow:
- Fast Fire 3 on supplied low mount. No numbers and I remember the dot on the hood with the low rails.
/moderator edit:
See also this thread for further pictures:
SP5 Rail and Mount Combinations Photography Project
Update 11/28: Project isn't dead yet. Sorry for all the delays. Started a new business and remodeled the office which took down all my accessories and photography. New job has had be on the road going out of state a bit. Should pick back up this week and next! Thanks! Overview There has been a...
www.hkpro.com
