Howdy guys.
Now that my .308 DPMS is firing/feeding properly, I need to tackle the issue of my BUIS.  I've got the DPMS Mangonel on the front and rear, and while out to the range yesterday, decided to sight these in.  What I found was that I cannot put in enough elevation to compensate for the difference in height between the rear rail, and my quad-rail gas block that I have the front sight mounted on.  Since everyone that has a DPMS .308 (except the new AP4) has this added height on the rear Picattiny Rail, I figured someone here would be able to advise me on what I should do.  For instance, do I need to purchase their Extended Height Gas Block, or how about the YHM gas block sight; I think that comes in one of two different heights...  
While we're on the subject, I'm thinking of trying out on on the Cross Hair Posts (dublex style), and was wondering if anyones tried these yet, and what the verdict is.
Thanks for your help.
Robert

Interesting question you should ask,

I was just looking into the same situation, how I was going to mount BUIS on my DPMS .308.

My problem was that I have the round gas block and hand guard so I had no where to mount the front sight.

I spoke with Shane at DPMS and he gave me 2 options,
1. Purchase the DPMS  “High” Railed Gas Block, the rail on it is the same height as the “high” rail on the receiver.
2. Purchase the DPMS “High” Quad Rail Handguard, which will also be the same height as the “high” rail on the receiver.

If you already have a gas block with a rail, you would also have another option, which may also be cheaper, which would be to add a simple riser on the top of the block.
Here is one example that might work, they would raise your front sight ½”
Riser

I am not sure if that would work, or if it would give you the opposite problem and make you front sight to high. I would guess you could probably get a rough estimate in the height difference between your gas block rail and your receiver rail.

Good Luck, Let us know how it works out.
“Capt Richardson”

Thanks Capt'n.  
Well, I too spoke w/DPMS, and I've purchased the higher gas block.  Earlier in my working up this rifle, I had acquired a YHM .5" adapter to raise the block, but I sold it as I didn't think that I'd need it after all!  In actuality though, I really didn't like the way that it made the front end look; too many gizmo's goin on, so I'm glad that I've taken this path.
Robert

OK, I'm back into this topic once more!
I'd been speaking w/Mark at LaRue Tactical about my problem of the SPR mount knocking into the rear BUIS and what to do about it, and he suggested a Totally different approach to the issue of 'iron sights', and suggested a JP point Micro-electronic Reflex Sight.  I hadn't considered these before as I figured 'electronic' was just another gizmo to fail when the chips were down.  
Anyone care to address this idea?  I'm going to paste this onto the 'optics board' too.
Robert

Hey Robert,

Still not sure what you are trying to do with your .308? Once again it is hard to give advice without knowing the details. Can you give some type of explanation on how you plan on using your .308? Close, Mid, or Long Range, Stationary or Moving Targets, 2 Legged, 4 Legged, or Paper Targets? Or a mix of the above?

I am in the process of overhauling my .308 to try and make it more versatile, practical, and reliable when it comes to Optics / Sights. My original setup was a “High Power” Scope which worked great for “Mid-Long Range”. My concern was that I had no backup in the event the scope went down. I also had no way to get a quick shot on a close up target especially if it was moving. I had originally planned on going to BUIS (backup iron sights), however I would have to pull the scope off to get a clear line of sight with them. I was not real big on that idea so I did some work and came up with the following setup which I am in the process of purchasing and assembling:
-   Primary, Long Range – High Power Scope (20 Power), on ARMS Rings to allow quick removal
-   Primary, Close Range – “Miniature” Red Dot (ATN Ultra Sight Digital Compact), mounted above the scope using the ARMS Tactical Ring Rail
-   Secondary / Backup – Folding Front & Rear BUIS, mounted on the handguard and receiver rails

I think this setup pretty much covers it all. The Scope will cover Long Range, the Red Dot will cover Close Range, if they fail they can be removed in seconds and the BUIS can be used.

My only concern with this setup is the ATN Miniature Red Dot, the 2 concerns are:
-   Size and Weight, and how they will impact the handling of the Rifle
-   Construction / Durability, will it hold up
I have had feedback that says it is great setup, and feedback that says to go with a Docter or JPoint Miniature Red Dot. Given that I can get an ATN for $140 versus $250-$350 for a J-Point or Docter, I will be a guinea pig and give it a shot!

As soon as I get it all put together and make it to the range I will be posting a report and some pics.

Good luck with yours, let us know how it goes,
“Capt Richardson”

Hey Capt'n.
Yip, I'm right there with you on your set-up and the reasons for it.  Same same.
As for the price of the JPoint though, I've seen them on Ebay new for $150; would that alter your choice?  They're so light and unobtuse...
And, you've GOT to post a picture when it's all said and done!
Mark @ LaRue sent me this one:

pg.photos.yahoo.com/ph/floydsflock/detail?.dir=/bc84&.dnm=6c93scd.jpg&.src=ph

Robert

Robert,

I also saw some JPoints on eBay for $150, however the ones I saw did not come with a mount that would work on an AR Rail. That being the case you would also need to buy a mount that would run you another $25-$50. That still puts it at least $30-$50 more that the ATN.

I actually just got the ATN today, and on initial inspection it looks really nice! The things I like so far:
- The housing is pretty “beefy”, especially when compared to the JPoint or the Docter. Don’t get me wrong it is not as “beefy” as an EOTech, but there seems to be enough material there to keep the glass from getting beat up under reasonable handling.
- You can select 3 different reticle patterns, Dot, Tri-Post, Tri-Post with Dot, unless I am mistaken you only get a Dot with the JPoint or the Docter.
- The intensity of the reticle automatically adjusts to the lighting conditions

While there is no question that it is bigger than the JPoint or the Docter, and I would probably not want to mount it on top of an ACOG or Compact Size Scope, I don’t believe that I will have any problem mounting it above my Full Size High Power Scope using the ARMS Tactical Ring Rail.

I will try to post some pics of the ATN by this weekend. Unfortunately it may be another week or two until I get all of the parts I need to complete the Optic / Sight upgrade on the .308, but as soon as I get it together I will post pics.

Thank,
“Capt Richardson”

PS: I could not get your link to work.

Well, I have the AP4, so I can't be of much help, but I'll post some pics of my setup anyways:  EOTECH w/ DPMS standard BUIS.

tag

OPP's, sorry about the bad link up above!    I did change it up there, but try this one:

pg.photos.yahoo.com/ph/floydsflock/detail?.dir=/bc84&.dnm=6c93scd.jpg&.src=ph
I am about to order one of these JPoints, but I REALLY wish I could get some feedback from differing points of view first!  I gotta say though, when a guy like Mark from LaRue say's it's a good way to go, well, you've got to like the source!  I know there are tons of options, and this seems about as good as any for this application (redundant 3 sight set-up).

Anyone?  I think that I'll paste this over onto the optics page, and go fishin there too!

Robert

Here are some photos:

http://i26.photobucket.com/albums/c131/captrichardson/ARScopeSight.jpg

http://i26.photobucket.com/albums/c131/captrichardson/ScopeSightSide.jpg

http://i26.photobucket.com/albums/c131/captrichardson/ScopeSightTopReticle.jpg

The first step in the Scope-Optics rebuild, got the ARMS mounts with the Tactical Rail and mounted the ATN. I stuck it on one of my .223 Long Range ARs for the photos, my .308 is still in pieces. The scope with it is a Springfield 3rd Gen, 6-20 x 56.

I am real happy with ATN as far as size and weight go, and the form and function seem to be real good so far. I definitely get the feeling that it is also going to do pretty good in the durability dept.

Not to say I will not consider a JPoint or Docter down the road, but for now I am definitely sticking with the ATN.

As soon as I get the .308 back together, and make it out to the range I will post some more info and pics.

Thanks,
“Capt Richardson”

Here are some more photos:
The ATN and an EOTech side-by-side for comparison. Sorry I don’t have a JPoint or Docter for comparison.

http://i26.photobucket.com/albums/c131/captrichardson/ATNEOTechRear.jpg

http://i26.photobucket.com/albums/c131/captrichardson/ATNEOTechSide.jpg

http://i26.photobucket.com/albums/c131/captrichardson/ATNEOTechTop.jpg

Thanks,
“Capt Richardson”

Well, guess what?  I talked to John @ JP products about the 'JPoints' on ebay, and found out that they're 'knock-offs' w/questionable pedigree's.  He told me that they were in contact w/the people selling them, and were trying to get these people to take JP's name out of their auctions...
So, now that the playing field is more level, price wise, I'm re-weighing the merits of each option.
Anymore input...?
Robert

Oh, and one more thing...
I went ahead and purchased a LaRue mount that will work for JPoints or Docter sights with my LaRue SPR.  I could sell this and get something that will work for any optic that I get, but what other mount will work in conjuction with my SPR??
Thanks,
Robert