AR15 - BUIS to temporarily act as primary

Status
Not open for further replies.
Bobson

Bobson

Member
Joined
Aug 9, 2011
Messages
4,293
Location
Kendall County, TX
I've been shopping around for an AR15 and will be buying soon. This will be my defensive rifle. The upper has a fixed front sight post, but no rear sight. Eventually I'll get a micro Aimpoint for it, but for now, I'm going to select my rear BUIS and just use the irons as primary sights.

I need some help choosing the rear sight. I know of the DD A1.5, which is a top contender. I've also seen nearly endless rave reviews for the Troy Folding Battle Sight. That said, I've heard the occasional "I'll never do business with Troy" here, and that's enough to have me wondering if Troy deserves my business. I'd love to hear input on their sights, and also fill me in on what your problem is with them as a company, if applicable.

The Troy has a same plane aperture, while the DD does not. Apparently this means the zero changes when switching apertures with the DD A1.5, but not with the Troy... Can someone please clarify this for me?

My main concern (and it may not even be that serious) is neither of these have elevation adjustment. I know that's not super serious for a backup sight, but if this is going to be my primary sight for 6-12 months, maybe it's something I need to have. FWIW, if it's decided I do need elevation adjustment, I'm pretty well settled on the LMT Tactical Rear... Maybe I should just go with that and call it a day.

What do you guys think? Should I bother with the LMT Tactical Rear sight for the elevation adjustment, or pick something less bulky without it for 6-12 months of plinking and practice?

Note that if you're going to recommend a different product entirely (which is fine), just know I'm not interested in the MBUS line. Nothing against Magpul, I just don't want a composite sight, even as a backup.

Thanks in advance for any experience-based advice.
 
Last edited:
You can make all your height adjustments with the front sight. I use a non folding rear sight with a red dot (1/3 co-witness) with the fixed front on my rifle.
 
If you're planning on upgrading to an optic at some point, I would just choose a basic rear sight like a Magpul. Odds are you won't be using it much before you add a red dot anyway.
 
On the military iron sights, the small aperture is used to zero the rifle at 300 yards. At this setting, when flipped to the large aperture, the zero distance will be approximately 200 yards. Makes sense in that you'd use the large aperture in low light or moving targets, which you really would not be engaging at such a long range as 300 yards.

The 300 yard small aperture zero puts the bullet several inches high at the midrange distance of 150 yards, whereas the large aperture will have a flatter trajectory out to 200 yards, since it is calibrated to the closer zero range. (edited to clarify my description, this is a bit tricky to explain) For a better description see the post below by Molon from ar15 who posts exceptionally well done pieces on the website.

http://www.ar15.com/forums/t_3_18/497571_0_2___The_A2_Rear_Sight_Aperture.html

I have the DD sight, and it is well made and pretty slim. If the budget were tight, you could get a military carry handle and cut down the front, for a rear sight similar to the LMT. In my experience, I like a red dot sight with the fixed irons in the "lower 1/3rd" view, and I just ignore the irons and use the red dot. A folding rear sight would cost a little more up front, and might not be as utterly bullet proof as fixed irons, but you can keep them down and not have any interference with a red dot or scope. It's really all preference vs. cost. If it were me, I'd do irons like the DD or LMT, and a 1/3 red dot mount. If I had the extra bucks for the folding sight, I'd consider a reasonably priced quality model.

For iron sights and AR general use, once the irons are zeroed, I never adjust them anyway, and like the previous post mentioned, you can adjust elevation on the front sight.
 
Last edited:
I looked down my nose at Magpul BUIS as plastic junk until I read Andrew Tuohy's drop test results:

http://kitup.military.com/2012/07/back-up-iron-sight-drop-test.html

"The last set of BUIS was the Magpul MBUS. Damage was purely cosmetic and the sight remained fully functional. Point of impact shift was less than 1 MOA. Unlike the other sighting devices, a second drop was performed. Results did not change, and the sight remained functional."

If I wanted a match sight, I would be all about adjustments and whatnot, but this is a BUIS - its One Job is to still be working after something bad enough to damage the optic has happened.

Also:

"One thing I did not mention in the post which was sent to KitUp (due to word count limitations) was that after dropping the MBUS twice, I picked the rifle up, held it over my head like the maul I used to split seasons’ worth of firewood while growing up in Alaska, and swung it down on a concrete shooting table, with the MBUS taking all of the impact. It did not break or shift POI by anything more than 1MOA.

My opinion of the MBUS went from “cool airsoft gear bro” to “wow.”"

http://www.vuurwapenblog.com/reviews/tests/buisoptic-drop-test/
 
Matech is used on military issue rifles and what I am putting on my rifle for the same reason as you.
 
Clearly a gross oversight on my part :eek: :eek: - I didn't realize you can make elevation adjustments with the front sight during sight-in. I thought it only allowed for windage.
 
"I didn't realize you can make elevation adjustments with the front sight during sight-in. I thought it only allowed for windage. "

To be clear, AR front sights only adjust for elevation. The rear adjusts for windage. Some rear sights, after being zeroed, also adjust for range (elevation).
 
Folding sights will make you "future proof", for when you decide to install an optic. That said, DD fixed sights are awesome for a simple carbine. I have tried a few of the surplus Matech's and they all had weak detents that would allow the rear sight to deploy under recoil.

One thing to note, for a fixed sight only rifle, a barrel mounted front sight is superior to a handguard mounted unit. Even the stoutest free float's generally have pretty noticeable flex when you put pressure on them, which will throw off your zero. If your not shooting for groups though, it likely wouldnt matter much.
 
Just get the DD, it's absolutely solid and uses the A1 windage adjuster so it stays zeroed. Elevation is adjusted on the front post, and even with the rear elevation knob on the A2 sights, once it was zeroed I never touched the elevation.

The 0-2 aperture is not supposed to be same plane. The small aperture is meant for longer precise shots when zeroed at 300 yards, while the 0-2 is meant for rapid shots using a 200 yard maximum point blank aiming zero.
 
For a defensive carbine, I'd opt for the DD, Magpul or (don't laugh until you read the details) UTG.

About UTG sights, read the packaging carefully and make sure you're buying an American made product. There's also a line of UTG stuff made in China that is vastly inferior. I wouldn't buy one mail order because you can't verify you're getting a decent part versus a Chinese knock-off.

If the rear sight has elevation adjustment, set it to the 0/300 mark and use the front sight to ajdust POI to POA. Zero a 50 yards and you'll be zeroed to roughly 300 yards. Just remember that from point blank to roughly 20 yards, you'll need to hold high about 2 inches due to sight height over bore.
 
If I were in your situation, I would probably go with the DD A1.5 rear sight. Its solid, well made, and affordable. Magpuls are not a bad option either, but if irons were going to be my primary sighting system for an extended period of time, I would want the fixed rear sight.

Matechs were issued with most of our rifles and carbines, they work, but I never liked them much. They also liked to break at the mounting screw or mounting clamp/claw.

No experience with LMT.

I will not do business with Troy. Google "The hiring follies of Troy".
 
Thank you all. After reading the posts here, along with continued research over the last few days, I've chosen the DD A1.5.

I'll post a pic and review of the rifle as soon as I can. Gonna be a variation on BCM's RECCE 16, using separately selected BCM upper and lower.
 
Let us know how it works out for you. I have the DD 1.5 as my primary sight and really like it. I like the elevation adjustment feature on the MaTech but the fip up portion looked to me like it might break easily. I think it would be ok as a back up sight where it spends most it's time folded down. But for use as a primary sight where it would remain deployed all the time, I wanted something more solid looking and not a "flip up".

Also I would suggest zeroing it at 50 yards. With 55gr bullets and a 50 yard zero trajectory is such that it will hit about dead on again at 200 yards, with very little "rise" in between 50 and 200

I hear alot of people talk about 25 yard zero and being "dead on" again at 300, but the problem with that is you'll be shooting several inches high in the middle of that range (say 175 yards).
 
David4516 said:
Let us know how it works out for you. I have the DD 1.5 as my primary sight and really like it. I like the elevation adjustment feature on the MaTech but the fip up portion looked to me like it might break easily. I think it would be ok as a back up sight where it spends most it's time folded down. But for use as a primary sight where it would remain deployed all the time, I wanted something more solid looking and not a "flip up".

Also I would suggest zeroing it at 50 yards. With 55gr bullets and a 50 yard zero trajectory is such that it will hit about dead on again at 200 yards, with very little "rise" in between 50 and 200.
Click to expand...
Thanks for the tip. Hadn't thought a lot about this previously, but 50/200 seems like a pretty good way to go. I'll probably use the next few weeks to look further into this sort of stuff while waiting.

What's a typical zero for guys who use their AR for HD? Does it even matter that close up? Only time I ever shot a rifle closer than 100 yards, it was another guy's AR15 with an Eotech and I have no clue where it was zeroed.
 
50 yard zero is pretty hard to beat for most any practical use. At close range, inside 50 yards, you will be at most shooting a couple inches low.
 
Jackal said:
50 yard zero is pretty hard to beat for most any practical use. At close range, inside 50 yards, you will be at most shooting a couple inches low.
Click to expand...
Couple inches low is a lot better than a couple inches high. 50 yard zero might just be the way I go. Thanks fellas.
 
Keep in mind that the DD uses a 0-2 large aperture (meant for targets from zero to 200 yards). The center of the large aperture is slightly lower than the small aperture, and is designed to provide a slightly lower trajectory for short range point blank shooting. Both the 50/200 and 25/300 zeros have the bullet trajectory rise several inches above the line of sight in midflight. I would try zeroing the small aperture for a 25/300 zero, then flip over to the large aperture and verify if it's holding a 50/200 zero. If you zero the small aperture for a 50/200, the large one might only zero at 100 with no rise above the sight line, limiting your maximum point blank range.
 
I'm attaching the numbers for the 50 yard zero. This is for my own hand loads using 55gr Hornady soft points with flat base, the BC is 0.235 and muzzle velocity is 2,800 feet per second. This is with a 16 inch barrel, 1:9 twist rate. I have gotten factory rounds to chronograph at higher velocity so I think the trajectory would be a little flatter with them.

Both the 50/200 and 25/300 zeros have the bullet trajectory rise several inches above the line of sight in midflight
Click to expand...

The 50/200 won't rise more than 1 inch in mid flight. The 25/300 zero will have you more that 7 inches high in mid flight
 

Attachments

  • 50_yard_zero.jpg
    50_yard_zero.jpg
    53.4 KB · Views: 9
Ok to make this more clear I did a side-by-side comparison (see attachment)

The 50/200 zero is great for close range but it starts to drop like a rock at distance. But honestly I'm not going to be making super long range shots with my iron-sighted carbine anyway. If I need to shoot at 300+ yards I'm going for a bolt action with a scope...
 

Attachments

  • zero_compare.jpg
    zero_compare.jpg
    68.8 KB · Views: 12
Status
Not open for further replies.

Similar threads

minutemen1776
  • Locked
MBUS or Troy?
Replies
11
Views
2K
Fishbed77
F
D
  • Locked
Having some elevation trouble with Troy backup sight on AR-15.
Replies
7
Views
810
ny32182
N
G
  • Locked
ACOG with BUIS - Will only Troy fit?
Replies
5
Views
1K
gtomax
G
franconialocal
  • Locked
BUIS minimum mounting distance??
Replies
2
Views
4K
franconialocal
franconialocal
S
  • Locked
Please help me choose a BUIS for my AR
2
Replies
28
Views
2K
Gary G23
G
Back
Top