Hello...
I recently inherited an M&P15 Sport II. I want to put a red dot on it for absolute co-witness, as I have another rifle set up like that. I used a 1" riser on my other rifle and mounted a TRS-25. I'd like to put a Holosun 507c on the M&P15. Do I need a riser for the Holosun 507c to absolute co-witness? The M&P15 currently has Magpul flip-up, adjustable metal sights. Can you guys give me some red dot options and tell me what parts (risers or anything else) I will need to absolute co-witness with my current setup? Thanks in advance. You guys are awesome.

The 507c is pretty small for an AR isn't it?

I have a Holosun 510C on an AR pistol that is absolute co-witness with Magpul sights.

The Trijicon MRO works great for me. It comes with either a co-witness or lower 1/3 co-witness mount. I have the lower 1/3, just my preference.

Thanks, yous guys. I'm looking at the 510C. Sorry for asking stupid questions. I'm new to AR's.

I have the 510C GR on my Sport 2 and love the sight. Was told it does cowitness, have not spent much time checking as rangetime is a bit limited so I work with the optic when able.
I can say the customer service at Holosun was great in answering my questions as this was my first AR and first optic. Just an fyi.

Best way to learn or find out something is to ask a question.

None of use were born with gun knowledge.

Another vote for the 510c GR.

I'll just share my brief take, It's a rifle, not a handgun or shotgun.

Ditch the red dot idea and put a quality low power variable scope on it with 45 degree offset MagPul flip up irons.

And you're there, done deal.

Or simply add a 3x magnifier.


Plenty of videos on Youtube comparing magnifiers vs LPVO scopes.

And I liked it so much I bought another one for my Barrett REC-7 I would highly recommend one to anyone for a carbine.

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Palmetto State Armory has this Sig Sauer Romeo MSR 1X20mm Green Dot Sight, 2 MOA #SOR72002 red dot on sale for $79; what do you think about it?

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Definitely opt for the 510C. 507 is too small for quick target acquisition on the AR; be it SBR, etc. Without the spacer, the 510C provides absolute. The 510 is large. Make sure you keep it on the upper only.

Another vote for the HS510C for ~25-50yd. I also like my Vortex PST 1-6x24 for ~100yd+ stuff.

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I like the Holosuns as well but I have the 512C, think of it as a completely enclosed 510C. The 512C has a closed emitter design and a QR battery compartment. I really like my 512C: Attention Required! | Cloudflare

Holosun 510C works great for me.

I purchased the 510C. I did consider the 512C, but found the 510C for $250 shipped. Just waiting for it to get here. I'm pretty excited about it. I do want to thank all of yous guys for always helping me. The information and experience you all provide has guided me to some really great purchases.

I picked the Sig Romeo MSR for my Tippman Arms M4-22. I wanted to try an inexpensive green dot to see if I liked it before possibly stepping up to a LPVO. It performs well enough for plinking and targets and at 50 yards I had no trouble keeping groups under 2". With the supplied high mount you get an absolute co-witness with MBUS sights. My only problem with it or any other red dot is my astigmatism, though not very bad, keeps me from seeing a sharp crisp dot.

I sighted in the 510c over the weekend. It was pretty much dialed in right out of the box, as were my mbus pro sights. Only took about 10 shots for each to get good grouping at 50 yards. Then 90 shots of fun.