T1: Fixed Irons/Lower Third vs. Folding rear/Absolute

[Meplat]

So I have this new 14.5 middy build (thanks, BCM!) with a regular FSP, and I'm trying to figure out what I want to do for a rear sight and optic (T1) set up.
I'm considering either an LMT tactical/adjustable fixed rear sight or a KAC micro 200-600. For the T1, I'm stuck between a lower third co-witness with a fixed rear, or an absolute co-witness with a folding rear (lower third still an option for the latter).
I've used the search function on this site and looked around quite a bit elsewhere and found the various reasons for one or the other, so I understand the merit to each, but I guess what I'm asking is:
What are your suggestions and opinions on which one to go with? Convince me, please.

Open to suggestions for alternatives for the rear sight, whether it be fixed or folding.

[Belmont31R]

Lower 1/3rd with KAC 300M.



You don't need the 200-600M on a 14.5" gun. The 300M micro would give you the same ability + its better for close in shooting since the aperture is larger.


1/3rd because its a more natural head position, easier to find the dot between shots, ect. The "absolute cowitness" height is the same as iron sights, and that height was developed because you need a more consistence cheek weld when shooting irons (aligning 2 sights vs. 1 with an RDS). You don't need to bury your cheek into the stock to shoot with an RDS.

[Meplat]

Lower 1/3rd with KAC 300M.



You don't need the 200-600M on a 14.5" gun. The 300M micro would give you the same ability + its better for close in shooting since the aperture is larger.


1/3rd because its a more natural head position, easier to find the dot between shots, ect. The "absolute cowitness" height is the same as iron sights, and that height was developed because you need a more consistence cheek weld when shooting irons (aligning 2 sights vs. 1 with an RDS). You don't need to bury your cheek into the stock to shoot with an RDS.

Great points, Belmont, and thanks for the post. I think I'm sold on the lower third co-witness based on your reasoning. I'll take the 300m into consideration. Still looking for opinions or suggestions on rear sights, fixed or folding.

[markm]

If I were going for a fixed rear sight, I'd pass on the cast LMT rubbish and buy a full Forged carry handle from BRAVOCOMPANY and cut it down.

Not only will you get a better sight.... it's CHEAPER!!

[Meplat]

If I were going for a fixed rear sight, I'd pass on the cast LMT rubbish and buy a full Forged carry handle from BRAVOCOMPANY and cut it down.

Not only will you get a better sight.... it's CHEAPER!!

I am, admittedly, inexperienced when it comes to a lot of the varieties of AR products there are, BUIS included, but I was under the impression that the LMT sight was very robust and quality. May I ask why it's "rubbish", aside from it apparently being cast? Unfortunately, I won't be able to cut anything down as I lack the necessary tools to do so, nor would I want to chop my new $100+ sight.
Additionally, what would you say of the Daniel Defense, Troy, and LaRue offerings for fixed rear sights? Any other suggestions?

[cop1211]

Love the Larue.

[mkmckinley]

I've never owned the LMT sight so I can't comment on its quality. In my opinion the Larue/Daniel Defense/Troy style fixed BUIS are the best design. I have the Larue sight and it's the best of its type that I've used; simple and very rugged. I'm sure someone will come along and disagree but the chopped-carry-handle rear sight is pretty much obsolete.

That said you can have the best of both worlds with a folding rear and a lower-third cowitness. Personally I'm a little faster without the clutter of a fixed rear.

[Meplat]

I've never owned the LMT sight so I can't comment on its quality. In my opinion the Larue/Daniel Defense/Troy style fixed BUIS are the best design. I have the Larue sight and it's the best of its type that I've used; simple and very rugged. I'm sure someone will come along and disagree but the chopped-carry-handle rear sight is pretty much obsolete.

That said you can have the best of both worlds with a folding rear and a lower-third cowitness. Personally I'm a little faster without the clutter of a fixed rear.

Thanks for the input, mcmckinley. I am also coming to the conclusion that the LMT may be a little chunky and pricey for what it is, and I think something like the LaRue would be a better choice.
That said, does anyone care to comment on the durability/robustness of the KAC BUIS' and any problems/wiggle they might have? Specifically the micros. I have used a Troy rear BUIS, but over the last year or two I have noticed it get more and more wiggle and play in it.

[kartoffel]

The LMT is a fully functional A2 rear sight with multiple apertures, windage and elevation adjustment.

Comparing a BUIS to an A2 is like comparing one of these to a real tire.

[MookNW]

I went from a 6940 set-up ( matech buis, flip up gas block front sight) with an ML3 in larue lt150 to DD front and back fixed sights with a aimpoint micro in a DD fixed mount. My first concern was that I would miss the flip up sights while using my aimpoint, but after running this set-up I am completely thrilled. Lower 1/3keeps the irons out of the way when I'm shooting the dot, and leaves enough clearance to get a good picture through the irons. Just my opinion.