gnatshooter Posted April 26, 2014 Report Share Posted April 26, 2014 (edited) Friends, You might remember me from the here. Well, I've finally bore-sighted my DPMS LR-308 using an adjustable front sight base that Brownell's/Lipski calls a "competition barrel band". The result: I had to adjust the front sight to the very limit of its upward range. So high, in fact, that the top section of the sight base is only barely attached to the bottom section that clamps onto the barrel. I am not happy with this result. At its current adjustment, the top of the front sight post is exactly 3" above the center of the barrel/bore. My question is, does anyone know where I can get a front sight like this, with the top of the sight post 3" above the bore, that fits a 0.720" (DPMS HBAR) barrel? (It needs to clamp onto the barrel.) Parts suppliers are really lazy when it comes to giving actual measurements for their parts, and I'm hoping someone here has a front sight like this that has those measurements, or knows of a source for them. There are other sight bases or complete sights out there that you see clamped on "tube guns" and "space guns", but measurements for those are also hard to find. One of them would be a fine solution for me, too. Many thanks! Edited April 26, 2014 by gnatshooter Quote Link to comment Share on other sites More sharing options...
Robocop1051 Posted April 26, 2014 Report Share Posted April 26, 2014 Check out Precision Reflex. PRI make a bunch of different tower sights and they have always responded to my questions. Also, Armalite makes a clamp on style A2 front sight gas block. Quote Link to comment Share on other sites More sharing options...
blue109 Posted April 26, 2014 Report Share Posted April 26, 2014 (edited) any way you could use a small riser on that barrel band? could you list your whole setup again, or post a pic? really seems like you are.trying to reinvent the wheel here. I have that A2 sight you posted a link for, and I know a few others do as well. I'll get you a measurement when I get off work if Nobdy chimes in. the problem will be that it's made for .75 barrel, so a shim might be needed. Edited April 26, 2014 by blue109 Quote Link to comment Share on other sites More sharing options...
unforgiven Posted April 26, 2014 Report Share Posted April 26, 2014 How about these guy's brother : http://www.creedmoorsports.com/shop/home.php?cat= Quote Link to comment Share on other sites More sharing options...
gnatshooter Posted April 26, 2014 Author Report Share Posted April 26, 2014 any way you could use a small riser on that barrel band? could you list your whole setup again, or post a pic? . I could use a small riser if someone makes one. My setup is listed as the first post. I'll try to wangle a pic from this end if I can find the camera. I have that A2 sight you posted a link for, and I know a few others do as well. I'll get you a measurement when I get off work if Nobdy chimes in. the problem will be that it's made for .75 barrel, so a shim might be needed. The 'height' (distance from bore to top of post) on the standard A2 sight is supposed to be 2.6" which is 0.4" too short of the minimum height I need. The 'barrel band' that I'm working with is drilled for a 0.732" barrel, so a shim from one thickness of a Mountain Dew can was enough shim to make a tight fit. How about these guy's brother : http://www.creedmoorsports.com/shop/home.php?cat= They have the Phoenix Precision Ultra High Front Sight, which is only barely tall enough -- with a max height of 3.0", but at $212 I'd feel like I'd been raped. Sideways. Seems there really should be something better out there somewhere, anyhow. Quote Link to comment Share on other sites More sharing options...
gnatshooter Posted April 27, 2014 Author Report Share Posted April 27, 2014 (edited) Here's the pix of my setup, the front and rear sights. You can see the Dave Lauck rear leaf sight sits pretty tall on the rail. And you can see how high the front sight has to sit to line up with it. That tubelike thing you see at the top of the front unit is a 'globe' sight, which accepts various different reticles. If you look carefully at the front sight you can see it's been adjusted, basically, to its limit. Or maybe beyond its limit. Those two vertical pieces go through holes in the sight base and you can barely see the set screw that sits between them on the base. Edited April 27, 2014 by gnatshooter Quote Link to comment Share on other sites More sharing options...
blue109 Posted April 27, 2014 Report Share Posted April 27, 2014 (edited) is that rear sight taller than a standard fixed rear AR sight? hard to tell from the pics. have you thought about going with a 15" rail and ditching the barrel band idea to get the sight radius you are looking for? edit...i vaguely remember you having an aversion to rail mounted sghts... Edited April 27, 2014 by blue109 Quote Link to comment Share on other sites More sharing options...
survivalshop Posted April 27, 2014 Report Share Posted April 27, 2014 Your not the first to have a iron sight problem with a DPMS 308 AR . Might be some of the reasoning for rail height changes. What rear sight do you have on the rifle . Quote Link to comment Share on other sites More sharing options...
gnatshooter Posted April 27, 2014 Author Report Share Posted April 27, 2014 is that rear sight taller than a standard fixed rear AR sight? hard to tell from the pics. have you thought about going with a 15" rail and ditching the barrel band idea to get the sight radius you are looking for? edit...i vaguely remember you having an aversion to rail mounted sghts... The Dave Lauck sight I have measures a total of 1.635" tall, top to bottom. The distance from the top of the rail to the top of the sight is 1.40". I'm not so much against rail mounted sights, as against a short sight radius. Putting a front sight on the gas block rail gives me a sight radius of about 8 inches. I've shot it with that radius, and it's possible to get good groups, but it's a real pain in the ass to line up such a short radius. So that's why I'm trying to put a sight all the way out by the muzzle. I suppose I could fix this with a 15-inch rail but heck, life would be simpler if someone just made a front sight with the right dimensions. Heck, the right sight might actually be out there but they won't give the real dimensions on it. Your not the first to have a iron sight problem with a DPMS 308 AR . Might be some of the reasoning for rail height changes. What rear sight do you have on the rifle . The sight is a "D&L Sports Custom CQB Iron Sight" and here's the web page for it: http://www.dlsports.com/cqb.html Quote Link to comment Share on other sites More sharing options...
blue109 Posted April 27, 2014 Report Share Posted April 27, 2014 (edited) that armalite A2 is milspec height, or about 2.5" over bore (rough measure) so it's going to be too short according too your measurements. that rear sight you are using appears to be standard height so I'm puzzled why a standard height front sight won't work? are you positive you need something >3" over bore to line up? are you sure that barrel band is getting you up to receiver rail height to start with? edit: looking at your picture.....do you have the silly tall "target" height upper? if so, all advice given so far is null and void. Edited April 27, 2014 by blue109 Quote Link to comment Share on other sites More sharing options...
gnatshooter Posted April 27, 2014 Author Report Share Posted April 27, 2014 (edited) that armalite A2 is milspec height, or about 2.5" over bore (rough measure) so it's going to be too short according too your measurements. that rear sight you are using appears to be standard height so I'm puzzled why a standard height front sight won't work? are you positive you need something >3" over bore to line up? are you sure that barrel band is getting you up to receiver rail height to start with? All I know for sure is that my calipers measure the height (above bore) of the rear sight at 3 inches, and the height of the front sight (above bore) at 3 inches. The reason I want an adjustable-height sight that runs over 3 inches is that I want more positive engagement between the upper and lower parts of the 'barrel band'. Right now, there's maybe 0.15" of the upper part that engages with the lower part, and that's not very robust for running in the woods. Edited April 27, 2014 by gnatshooter Quote Link to comment Share on other sites More sharing options...
blue109 Posted April 27, 2014 Report Share Posted April 27, 2014 I made an edit you missed...what height rcvr do you have? is it the extra tall one? how tall from the charging handle to the top of the rcvr rail. Quote Link to comment Share on other sites More sharing options...
survivalshop Posted April 27, 2014 Report Share Posted April 27, 2014 (edited) I didn't see those photo's before with that post or they didn't load when I read it . Have you contacted the sight manufacturer of your problem or what you want to accomplish ? As said, you may need to find out your upper receivers rail height. Edited April 27, 2014 by survivalshop Quote Link to comment Share on other sites More sharing options...
Magwa Posted April 27, 2014 Report Share Posted April 27, 2014 I will bet a dime to a donut that there is something fishy with the reciever no way in 7 hells could you have a front sight that tall as per his pics...... unless that rear sight is too tall for standard height front sights it is one or the other..... why not use the standard carry handle and a A2 front sight.problem solved. I have a clamp on A2 sight on my Dissy I shimmed it with pop can strips it is rock solid and works perfect. Quote Link to comment Share on other sites More sharing options...
gnatshooter Posted April 27, 2014 Author Report Share Posted April 27, 2014 (edited) I made an edit you missed...what height rcvr do you have? is it the extra tall one? how tall from the charging handle to the top of the rcvr rail. The distance from the top of the charging handle to the top of the receiver rail is 0.525". Edited April 27, 2014 by gnatshooter Quote Link to comment Share on other sites More sharing options...
392heminut Posted April 27, 2014 Report Share Posted April 27, 2014 (edited) Yup, that's the extra tall receiver. Great for mounting optics but it kind of sucks for iron sights. I have the same receiver but I only run optics so it hasn't been an issue for me. Edited April 27, 2014 by 392heminut Quote Link to comment Share on other sites More sharing options...
blue109 Posted April 27, 2014 Report Share Posted April 27, 2014 dang man. wish you posted that part first. the hi top upper you have was designed for a scope with a huge objective, and makes everything else a pain. I think DPMS makes a railed gas block thst matches that height, but it's for the .9 bull barrels. other than that you will probably need something custom. the only freefloat rail that matches that upper is the obscenely heavy DPMS rail. honestly, your best and cheapest option is to buy a standard height upper and swap your parts over to it. Quote Link to comment Share on other sites More sharing options...
gnatshooter Posted April 27, 2014 Author Report Share Posted April 27, 2014 Well poop. Thanks for the help though! Quote Link to comment Share on other sites More sharing options...
blue109 Posted April 27, 2014 Report Share Posted April 27, 2014 the good news is you can score a standard upper under $200, and all your cool parts will work fine. additionally, your sights will be a half inch closer to bore axis. also easier to get a more natural cheek weld. I had the same issue and just sold my whole upper and built a new one exactly how I wanted it. take this as an excuse for upgrade :) Quote Link to comment Share on other sites More sharing options...
gnatshooter Posted April 27, 2014 Author Report Share Posted April 27, 2014 the good news is you can score a standard upper under $200, and all your cool parts will work fine. additionally, your sights will be a half inch closer to bore axis. also easier to get a more natural cheek weld. I had the same issue and just sold my whole upper and built a new one exactly how I wanted it. take this as an excuse for upgrade :) Thanks! I have problems with a cheek weld on this setup, too -- was thinking about a Magpul PRS stock so I could adjust the problem away. Quote Link to comment Share on other sites More sharing options...
Magwa Posted April 27, 2014 Report Share Posted April 27, 2014 I knew that was the culprit...... Quote Link to comment Share on other sites More sharing options...
N Jensen Posted April 28, 2014 Report Share Posted April 28, 2014 I have a upper that is higher than the standard flat top and had the same problem. I took a little work to figure out to lower the rear sight. But that was with a match rifle sight. Your rear sight was made for a standard flat top. Swapping out the receiver is the only to make your rear sight work. If you wanted to use your current flap top, I could send a picture of my match sight and how it mounts and get a good stock weld as well. Quote Link to comment Share on other sites More sharing options...
gnatshooter Posted April 28, 2014 Author Report Share Posted April 28, 2014 If you wanted to use your current flap top, I could send a picture of my match sight and how it mounts and get a good stock weld as well. I would like to see that picture and maybe a link to locate a seller of that sight. Quote Link to comment Share on other sites More sharing options...
gnatshooter Posted April 28, 2014 Author Report Share Posted April 28, 2014 the good news is you can score a standard upper under $200, and all your cool parts will work fine. additionally, your sights will be a half inch closer to bore axis. also easier to get a more natural cheek weld. Looks like I can keep things "all in the family" and get an upper receiver from DPMS, shown here. And the price is only $170. Thing is, can I run this receiver without installing the forward assist and ejection port cover parts? I don't feel a burning need for these features, but for instance, I don't want crap blowing back into my face through the empty forward assist housing. Or, if I install the forward assist, do I have to get a different bolt carrier? What looks like a good deal in an upper is starting to look more expensive. There's also this receiver from DPMS, more expensive at $200, looks like it doesn't have the port cover and forward assist, but no mention of whether it's the low-profile version or not. Y'all got any thoughts on these issues? Quote Link to comment Share on other sites More sharing options...
survivalshop Posted April 28, 2014 Report Share Posted April 28, 2014 Ejection port cover can be left out if you want , but as you said , might want to put the Forward assist in there ( inexpensive anyway, or if your present set up has one , swap it over ) ,just to make sure nothing blows back at you. No need to change BCG . Just swap out the parts & you will be good to go , except for re-sighting her in , that is . Quote Link to comment Share on other sites More sharing options...
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