iron sights: LMT vs Troy

[SubstanceP]

I'm trying to decide whether or not I should swap out the LMT Tactical rear and front sights that came with my CQB MRP 16" piston with Troy sights.

What are your opinions and why?

Thanks.

[Mute]

I'm not a particularly big fan of fixed BUIS so my answer's pretty obvious. I especially like the HK style front from Troy. Of course, I have a set of Magpul MBUS on the way and I'm dying to see how they compare.

[Jim_KT]

I'm trying to decide whether or not I should swap out the LMT Tactical rear and front sights that came with my CQB MRP 16" piston with Troy sights.

What are your opinions and why?

Thanks.

If you do quite a bit of shooting using the IBZ past 300yds then the LMT fixed BUIS might be a good bet. If not, then there really isn't much practical use (IMHO) for the elevation wheel. My primary carbine had the LMT unit, but now sports a Troy BUIS.

[aplinker]

I'm trying to decide whether or not I should swap out the LMT Tactical rear and front sights that came with my CQB MRP 16" piston with Troy sights.

What are your opinions and why?

Thanks.

How do you use your rifle? What kind of optics do you use?

[maxicon]

Here's my standard post on choosing a flip-up BUIS. If you figure out what features you care about and what you don't, it narrows it down a lot.

----------

Are you going to mount a magnified optic? If so, you need to consider whether the BUIS will fit under the scope and mount combo - some mounts (like the Armalite) are very low, and others (like the M1Sales) are quite high.

If it's for a red dot/Eotech style, there's a lot more flexibility.

For a magnified scope, you'll need a flip-up BUIS. For a non magnified optic, you can use a fixed sight as well, which is generally sturdier, but obscures part of your field of view.

A few things to consider when choosing rear flip-up BUIS, depending on if it's going to be a range gun or a SHTF gun:

- Will it be used for precision or long-range shooting? A small aperture is helpful for this. If the use is both close-up and long-range, a dual-aperture sight is useful.
- If it's multi-aperture, which one is deployed when it flips? Some flip with the large aperture deployed, others with the small. If you're not in a hurry, this won't matter, but some people care.
- If multi-aperture, do the apertures deploy in the same plane? Some deploy with an elevation shift to account for the range differences, others use the same zero for both apertures.
- Do you want the windage knob easy to adjust or shielded to prevent accidental adjustments? ARMS are exposed and easy, Troy is shielded.
- Does it have elevation adjustments? Some do (like the Wilson Combat), most don't.
- How easy is it to deploy or adjust if your hands are muddy or gloved?
- Does it latch in the up position, the down position, or both?
- Is it spring loaded, like the Matech or ARMS, or not, like the YHM-9680? Spring loaded will pop back into position if bumped, while non will stay partially deployed if bumped from the unlocked position.
- How protected is it from damage, both down and deployed?
- How robust is the detent mechanism? The Matech will wear over time and become easier to deploy (and eventually won't lock). For many, this doesn't matter, as their BUIS aren't used often.
- How many slots does it cover? This is important if you need to conserve rail space.

Figure out which of these are important to you and what capabilities you want, and it will narrow down the choices quite a lot.


Here's how to figure out if it will fit under your scope and mount.

- Measure the scope's eyepiece diameter, with flip caps if you're going to use them. Butler Creek usually adds about 0.1" to the diameter. If the scope's going far enough back so the eyepiece isn't over the BUIS, measure the diameter where it is over the BUIS.
- Divide that by 2.
- Subtract that from the centerline height of your mount or rings.
This gives the maximum height BUIS that will fit under that scope/mount combo.

For example, my Leupold VX1 4-12x40 eyepiece diameter is 1.7" with flip caps - divided by 2 gives 0.85". Mounting it in a 1" LaRue LT-104, which has a 1.41" centerline, would leave (1.41-0.85) = 0.56 as the tallest BUIS that would fit. As you can see from the list below, that leaves out many. This is one reason the Troy BUIS is so popular.

Here are some popular BUIS heights:

ARMS 40 - 0.95" folded (mine is 1.00" even)
YHM-9680 - 0.84" to the top of the windage knob, 0.74" to the top of the sight body
Matech - 0.75" folded at the elevation adjustment, off to the side, 0.6" closer to center
MI ERS - 0.75" folded
GG&G MAD - 0.625" folded
Magpul MBUS - 0.625" folded (not verified)
ARMS 40L - 0.61" folded (mine is 0.59")
Troy - 0.460" folded
MI MCTAR-SPLP - .438" folded
YHM QDS - 0.435" folded
KAC 300m - 0.315" folded