View Full Version : T1: Fixed Irons/Lower Third vs. Folding rear/Absolute
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
09-14-10, 18:41
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.
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.
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!!
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?
mkmckinley
09-14-10, 22:29
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.
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.
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.
http://farm4.static.flickr.com/3572/3396396247_cb3551ba39.jpg
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.
I was under the impression that the LMT sight was very robust and quality.
LMT used to have solid rear sight bodies that I assume were Forged. Then they switched to the cast bodies. The castings may be strong enough for most shooters, but A rear sight housing is a high bang potential area.
I've just grown tired of all the short cuts that LMT takes. None of it is supposed to matter, but between the MIM gas keys, cast sight bodies, straight FSB pins, and no park under the FSB, I don't know why people continue to buy LMT stuff.
Additionally, what would you say of the Daniel Defense, Troy, and LaRue offerings for fixed rear sights? Any other suggestions?
I've only tried the DDs. They seem rugged, but they're an extruded aluminum body. I don't want to intentionally whack them so see how much they can take, so.. :confused:
If I was building a gun to go into combat with, it'd definitely have a forged steel FSB taper pinned to the barrel and a real mil spec carry handle or cut down carry handle for a rear site.
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.
This is very good to know, MookNW. I was worried that going with a fixed rear would leave the sight picture on the T1 too cluttered and distracting with the mass of metal in the bottom of the optic. I think, for simplicity and durability's sake, this might be the way to go.
LMT used to have solid rear sight bodies that I assume were Forged. Then they switched to the cast bodies. The castings may be strong enough for most shooters, but A rear sight housing is a high bang potential area.
I've just grown tired of all the short cuts that LMT takes. None of it is supposed to matter, but between the MIM gas keys, cast sight bodies, straight FSB pins, and no park under the FSB, I don't know why people continue to buy LMT stuff.
I've only tried the DDs. They seem rugged, but they're an extruded aluminum body. I don't want to intentionally whack them so see how much they can take, so.. :confused:
If I was building a gun to go into combat with, it'd definitely have a forged steel FSB taper pinned to the barrel and a real mil spec carry handle or cut down carry handle for a rear site.
Good to know. I'll definitely look a little closer when looking at LMT products from now on. I'm not really keen on the idea of cutting down a shiny new carry handle. :eek:
Thanks for all the help, guys.
This is my first experience with a RDS and I went with a T1.
I bought the KAC T1 mount and the LaRue high mount for my work gun, 6920.
I mounted the KAC, thinking I'd like the absolute co-witness and took it to our range and shot for about 6 hours. This isn't normal, I shammed my way in.
The gun is all nice and zeroed and it wasn't too bad with the sights absolutely co-witnessed but I am thinking that the lower 1/3 is going to serve me much better on this.
After reading Belmont's suggestion, I guess I'll take the KAC off and mount the LaRue and go rezero.
Anyone want a KAC??? :D
This is my first experience with a RDS and I went with a T1.
I bought the KAC T1 mount and the LaRue high mount for my work gun, 6920.
I mounted the KAC, thinking I'd like the absolute co-witness and took it to our range and shot for about 6 hours. This isn't normal, I shammed my way in.
The gun is all nice and zeroed and it wasn't too bad with the sights absolutely co-witnessed but I am thinking that the lower 1/3 is going to serve me much better on this.
After reading Belmont's suggestion, I guess I'll take the KAC off and mount the LaRue and go rezero.
Anyone want a KAC??? :D
Want or want *to buy*? :p
Either way, I was under the impression that the KAC T1 mounts came with a spacer so that the user could use either absolute or lower third co-witness by switching out the spacer. At least that's what it says on KAC's website.
Want or want *to buy*? :p
Either way, I was under the impression that the KAC T1 mounts came with a spacer so that the user could use either absolute or lower third co-witness by switching out the spacer. At least that's what it says on KAC's website.
Disregard. User is an idiot. Today/yesterday was the first time ever using a red dot. Strictly been iron sights.
When I posted, I had just pulled my gun out and was thinking way too much and I kept trying to get a good cheek weld and was focusing on my fixed front sight, thus it left me thinking I had a absolute co-witnessed mount.
Funny thing is, during shooting today, I can remember not doing any of that and focused strictly on the dot.
I'm a f'n retard and will just keep my mouth shut and not ask stupid questions or add any dumb comments.
So the LaRue LT660 has got to go now...
Disregard. User is an idiot. Today/yesterday was the first time ever using a red dot. Strictly been iron sights.
When I posted, I had just pulled my gun out and was thinking way too much and I kept trying to get a good cheek weld and was focusing on my fixed front sight, thus it left me thinking I had a absolute co-witnessed mount.
Funny thing is, during shooting today, I can remember not doing any of that and focused strictly on the dot.
I'm a f'n retard and will just keep my mouth shut and not ask stupid questions or add any dumb comments.
So the LaRue LT660 has got to go now...
Don't be so hard on yourself buddy, we all make mistakes (except me). :cool:
Being used to nothing but irons and then jumping to something like a red dot can be confusing, but quick and easy to get the hang of usually. That's how it was for me at least. At least you got it all figured out now.
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