Need help choosing BUIS

[Jay S.]

Can someone please explain the difference between the Arms #40 A2 and the Arms #40L SP? I am going to order a Stag Arms upper as soon as I can get some more info. I plan on putting an Eotech on it if that helps.
Does the A2 stay fixed and the SP fold? I have read the SP stands for same plane. I'm confused.;g
Once again thanks for the help.

[USMCsilver]

The regular #40 is not "low cut"; i.e. it cannot be mounted under scopes and other optics. It does flip up and down and has a full size windage knob.

The #40LSP has a "same plane" aperature. The #40L, well, it is a "low" mount that allows you to mount a scope above it.

Look here: A.R.M.S. mounts. (http://www.armsmounts.com/catalog.php?action=110&cat_id=4)

IMHO, A.R.M.S. is the ONLY way to go!

[Jay S.]

Thanks for the reply. I'll probably order that tommorow.

[Bonk]

I have a 40A and an EoTech 512. The 40A and 40 both default to the large aperture, ie when you flip it up, you're looking through the large peeper. Rotate it to the back, like on a A2 carry handle, and you're looking through the small aperture. The 40L defaults to the small aperture, then you fold it down to reveal the large aperture.

Using a 40A or 40 with a conventional scope is difficult, but it can be done. I use a B-Square riser and extra high rings, and the scope, a 3-9x40 (when my EoTech isn't on there) clears my 40A just barely.

[Dennis in MA]

Originally posted by USMCsilver
The regular #40 is not "low cut"; i.e. it cannot be mounted under scopes and other optics. It does flip up and down and has a full size windage knob.

The #40LSP has a "same plane" aperature. The #40L, well, it is a "low" mount that allows you to mount a scope above it.

Look here: A.R.M.S. mounts. (http://www.armsmounts.com/catalog.php?action=110&cat_id=4)

IMHO, A.R.M.S. is the ONLY way to go!

DOOOODZ!!!!!

I have been considered WORTHY by USMCSilver!!!! I got me one of them 40's. And another (used) on it's way.

Heck, I'm also considering a Magpul stock too. ;)

I like mine. Altho on the current upper, it's slew pretty far right and the front-post is pretty high. But it works fine, so who am I to complain?

[USMCsilver]

Originally posted by Dennis in MA
DOOOODZ!!!!!

I have been considered WORTHY by USMCSilver!!!! I got me one of them 40's. And another (used) on it's way.

Heck, I'm also considering a Magpul stock too. ;)

LOL, glad I finally showed you the light. ;f Nice, ain't they?

Not sure what you mean about it being "slewed" far right? You mean that's what it took to get it to shoot straight? I don't think that's a sight issue. Also, what do you mean about a high front post?

Oh, and the Magpul rocks; but you already knew that.... ;c

[five-0]

I've got, and use, an ARMS #40 and it works fine.

But, if/when I get another BUIS, it will be a Troy flip-up. I like that the Troy locks into place and isn't held up by a spring.
Best

[glock19_fan]

Originally posted by five-0
I've got, and use, an ARMS #40 and it works fine.

But, if/when I get another BUIS, it will be a Troy flip-up. I like that the Troy locks into place and isn't held up by a spring.
Best +1

Most people seem to think the Troy BUIS are the best.

[Zagger]

I have tried personally or seen in action most BUIS made. I have seen many that are serviceable, but none that were better than the Troy.

[USMCsilver]

Hmm, maybe the Troy is worth checking out. Never seen one in person, though.

Some ***** about the spring loaded ARMS, but, to be honest, I've NEVER heard of an ARMS BUIS failing...

[Creeper1313]

I'll offer my own experience:
The Arms #40A2 works fine if the only optic you'll ever use on that rifle is the EOtech. Which is what I thought a year ago. However, a month ago I got an urge to also try out a 10x scope on my AR (my one and only rifle so far). This resulted in me having to sell my #40A2 and get a Troy (A #40L would have been fine too, but I decided to splurge). Had I owned the #40L, I would have already been set.

Luckily, the fantastically active Equipment Exchange at AR15.com lets you get back a good percentage of the money on AR things you try and decide aren't right for you, so you can be more adventurous. I sold my #40A2 in literally 15 minutes there and only lost $10 from what I originally paid for it.

[Sierra]

LMT or LaRue for a Fixed BUIS and the Troy for a flip-up are the best BUIS available in my opinion.

[dbrowne1]

Originally posted by Sierra
LMT or LaRue for a Fixed BUIS and the Troy for a flip-up are the best BUIS available in my opinion.

Those would be my choices, in those respective categories, as well.

[Dennis in MA]

Originally posted by USMCsilver
LOL, glad I finally showed you the light. ;f Nice, ain't they?

Not sure what you mean about it being "slewed" far right? You mean that's what it took to get it to shoot straight? I don't think that's a sight issue. Also, what do you mean about a high front post?

Oh, and the Magpul rocks; but you already knew that.... ;c

The rear sight is 1/2 between "top-dead-center" and the right side. Then the front sight post is, to me, very high. Almost to the rabbit-ears on either side of it. But at that, it drops in right where I want it. Well, now that I think about it, it might be an inch high at 50 yds. I wanted it dead-on at that range. If only to extend my Point Blank range. I think I'm reaching a bit far for practical purposes.

But I digress. I guess I need a 'bud to shoot it to make sure my eyes are on straight. Just seems wierd to be that far out of "spec." It is a cobbled-together upper, but that's pretty far off in my book. (DPMS 1/9 M4 bbl, Anchor Harvey forged upper, SE marked bolt-carrier. Of course the front sight could be whack and I don't know it.)

[USMCsilver]

Dennis, you need a high FSP since you're using a BUIS on a 16" upper. Standard problem for many. The normal post is used with a carry handle mounted sight. Find a taller sight and you'll not be having the same problem; granted, it'll still be "high" but it won't be about to fall outta the base.

[hayseed_40]

I need to vote for the GG&G A2 flipper. Like it and it is rock solid and durable. Looking on arfcom's EE to trdae for the LMT fixed rear. Thinking about getting rid of the folders.

[GregG17]

If you want to be cheap, I cut my carry handle and used some Alumablack on the site, that way I can save the money for an Eotech.her are some pics,

[GregG17]

pic 2 save your cash for now and put it towards an optic...

[Black Tiger]

I'm cobbling up an M4 type carbine and I will be buying this one instead:

http://www.gggaz.com/images/mad_buis/MadBuis.jpg

GG&G MAD BUIS (http://www.gggaz.com/products/madbuis.php)

with the Tritium inserts in it.

:cool:

[army_eod]

Originally posted by dbrowne1
Those would be my choices, in those respective categories, as well.

Agree on the LaRue. Mark gave me a discount on the BUIS. It is beatiful and co-witnesses perfectly with the EOTech that is mounted on the YHM EOTech mount. I will do business with LaRue anytime and his products and service cannot be beat.

Here is pic of the AR:

http://i33.photobucket.com/albums/d67/army_eod/gunstuff012.jpg

[Gmountain]

I like the A.R.M.S. 40L the best.

[Mad Ryan]

I love my Troy sights. They are totally solid and work really well together. Here's a couple of pix...

http://i49.photobucket.com/albums/f296/madryan/IMG_0010.jpg

http://i49.photobucket.com/albums/f296/madryan/IMG_0004.jpg

http://i49.photobucket.com/albums/f296/madryan/IMG_0005.jpg

[USPcompact]

I've got the Troy sights and like them, but they are not without issues.

From trapezoidal on ARF:

"There are more important engineering issues here.

A) Flipping from the large to small aperture or vice versa is not supposed to affect windage or bullet impact.

B) Windage shift is only supposed to be done by moving the windage knob.

Further clarification follows below.

1) If you zero the large aperture and switch to the small aperture, the point of impact changes. The compensation built into the Troy sight to account for it travelling along the threads when switching apertures (like a standard M16A2 does) has not been engineered properly. The result is that the impact will be approximately 3" from the point of zero at 100 yards when you switch to the other aperture. It doesnt matter if you zero with the large aperture or the small aperture...the point of impact will be about 3" off from the initial zero.

For instance...On an M16A2 government issue sight, the large aperture is off center to the center of the small aperture to compensate for travel on the threads as the apertures are switched from large to small holes. The Troy is also offset, however it is not offset correctly for the amount of rotation that it turns,because the Troy apertures are not L shaped like the M16A2 sight.

Simply put. If you sight in your gun at 100 yards with the large hole aperture.....then switch to the small hole aperture and shoot again, the bullet will about 3 hit inches off to the side from the previous shot.

2) The Govt. Issue M16A2 rear sight, the LMT rear sight, the ARMS sight and all current govt issue AR sights use 36 threads per inch on the screw that the aperture travels on. The thread pitch on the Troy sight is only 24 threads per inch. Having only 24 threads per inch means that it is much more difficult to get precision zero's because the thread is so much coarser.

3) The Troy sight windage knob clicks travel the aperture nearly twice as far as a government issue M16A2 sight, which makes it impossible to get precision zeroing like you can with a govt issue M16A2 sight.

4) The improper offset compensation between the apertures, the coarse 24 threads per inch, and the excessive travel between windage clicks, make it impossible to obtain precision shooting like you can with M16A2 type engineering.

The final results are, the AR15 or M4 can shoot a lot better than the Troy sight will allow."

All that said, it's a BACK-UP sight. I'm more concerned about the ruggedness of the sight and with it staying locked when deployed than I am about MOA accuracy. If I'm being forced to use my BUIS, my world really has gone to ****. ;g

[Eric911]

I recently added a YHM A1 BUIS to the collection. About $74 shipped at www.rainierarms.com. I've been very happy with it. One of the better buys.
http://img.photobucket.com/albums/v503/AR15forme/YHM%20A1%20BUIS/P1010452.jpg

[Sierra]

The Troy is the best (IMHO) flip up out there. It certainly is the most robust.

On another AR clone I am running an LMT fixed BUIS and it is very impressive and strong.

I have no complaints with the Troy and would not hesitate to get one. Its great with my Eotech 512.

[five-0]

Mad Ryan...what pistol grip is that? I thought I was familiar with most all of them, but that one escapes me...and it looks exactly like what I need!

[1811guy2]

Another + for the ARMS BUIS.

I have the 40L on mine. I went with it because the fit and finish is superb, is as robust as any other BUIS on the market, and it is contoured so that the 19S throw lever mount for my ACOG TAO1 fits flush against it. That may not seem like a big deal, but I am able to mount my scope over 1/2" more to the rear than with other mounts without using adapters that only increase the elevation of the mounting platform in order to clear the BUIS. That 1/2" is just enough to give me a comfortable cheek weld on the gun while keeping my nose off the charging handle. The eye relief on ACOGS is pretty short and requires you to have to really cinch up on the staock to get the full field of view. The 40L and 19S were designed to work together and eliminate this.

Two apertures are provided. The small is for 200-300 yards. The large is for 100 yards. The small sits on a different plane to compensate for bullet drop. You can also get the small aperture with a 500M cut in the top, setting it on different plane. The same plane model means that both the small and large apertures are on the same plane and will zero at the same point on the target at the same range.

[Mad Ryan]

Originally posted by five-0
Mad Ryan...what pistol grip is that? I thought I was familiar with most all of them, but that one escapes me...and it looks exactly like what I need!

Don't remember what brand it is. I picked it up from the local gun store for about $25 or so and I really like it. It's hard plastic, not spongey feeling like some of the ergo type grips I've seen. I'll try to get you a name or brand, but if all else fails, I'll pick one up and mail it to you.

[five-0]

Originally posted by Mad Ryan
Don't remember what brand it is. I picked it up from the local gun store for about $25 or so and I really like it. It's hard plastic, not spongey feeling like some of the ergo type grips I've seen. I'll try to get you a name or brand, but if all else fails, I'll pick one up and mail it to you.

Thank you, sir.