need BUIS recs for a DD MK18

[Jay Cunningham]

If you intend on using the Micro optic, having deployed front and rear irons and a TLR-1 at 12:00 is going to work against the whole point of having a reflex optic. That's going to be a busy, cluttered sight picture.

I think that there are several configurations that work better than others. If using a Micro, I'd opt for a standard (center) co-witness with either a fixed or deployed folding front and a rear folded down. I'd mount a Scout light offset at 10:30 or 1:30.

Now if you were going with something that has a giant field-of-view like a Trijicon SRS I'd recommend fixed BUIS.

[JRas]

KAC back-up iron sights, if you want to go for broke

Use the LaRue mount, QD capability

[Jay Cunningham]

What is the utility of a QD mount on an iron sight?

[BWT]

I'd endorse Troy, I use a fixes front sight and a folding rear and I'm happy with them from Troy. If you don't want them to obscure sight picture in anyway get a folding set, or if you prefer deployed cut the price in half and go fixed.

I'd recommend Loctiting the set screw, I have had one vibrate loose. But other then that, IMHO you get fixed sight performance and durability from Troy folding BUIS.

ETA: The sights not vibrating loose would be how I could feasibly see QD mounts. However, if you're screwing a sight to a QD mount... You would have removed that benefit.

[VolGrad]

What is the utility of a QD mount on an iron sight?

I interpreted the QD comment to a rec to stick with the LaRue micro mount rather than my plan to switch to a fixed DD micro mount. I could be wrong.

[Jay Cunningham]

Ah. I think I see.

[dnittler]

If running a light at 12:00, the DD fixed rail-mount front sight has cutouts for easy acces to the light switches. I think Vickers might had some input on that design. I've run an Aimpoint with an A2 front sights post, and I never notice it's there – does not seem cluttered at all.

I like an absolute co-witness so my cheek weld is consistent, which means I need to run folding rear BUIS. I've got Magpul's MBUS 2 and they are awesome. A quick bump with the palm and they pop up. Press down to put them away.

The Troy sights are prettier, but they are hard to deploy (press button while pulling up).

Oh, and great choice on the MK18.

[TGS]

If running a light at 12:00, the DD fixed rail-mount front sight has cutouts for easy acces to the light switches. I think Vickers might had some input on that design. I've run an Aimpoint with an A2 front sights post, and I never notice it's there – does not seem cluttered at all.

I like an absolute co-witness so my cheek weld is consistent, which means I need to run folding rear BUIS. I've got Magpul's MBUS 2 and they are awesome. A quick bump with the palm and they pop up. Press down to put them away.

The Troy sights are prettier, but they are hard to deploy (press button while pulling up).

Oh, and great choice on the MK18.

Couple questions:

My Troy sights don't require any button to be pressed in order to deploy. They just pop up. Are we talking about different Troy sights?

Also, why the fixation on a consistent cheek weld when using an RDS? Isn't a consistent cheek weld completely unnecessary with an RDS, and sort of counter to the advantages of an RDS with its flexibility/ease of use in positions of compromise? If an absolute co-witness is required, then why not just use irons alone since you're basically running irons anyway?

Thanks.

[JMS]

My Troys also only require the button to be folded back down, not to be deployed.

As for cheek weld, it's still desirable on the sole basis that it's part of the fundamentals and the ability to consume the gun. An RDS is simply more forgiving during those times when one is unable to achieve it (no need to line up more than one point like with irons, no scope shadow as with a magnified optic), but the "parallax-free" label on those things should read "as parallax-free as these things can be made." Light passing through a medium causes parallax, period (SCIENCE! ), so keeping that dot centered in the optic eliminated that as much as it can be, so getting a consistent cheek weld regardless of sighting system is still a best-practice.

Pat McNamara includes a proof-of-concept for that as a part of his curriculum. During the BRM/zeroing portion, students will take the dot and put it in some corner or clock position of their RDS; usually means altering your head position/weld. Shoot for best possible group, using the same target aimpoint as usual. There's a POI shift in that direction. Ergo, a proper weld, if achievable, is a good thing.