Mr_Roboto Posted November 20, 2016 Report Share Posted November 20, 2016 okay, so I bought a lower and upper from American Made Tactical and the upper is a Sportical style. Unfortunately I think they use their own height gas block. I'm doing a tube so I want to do a gas block front sight. I'd be up for a dorito if it's the right height, but a gas block sight is fine as well. Will a "gas block" height sight with an AR-15 railed gas block make everything fit or am I going to be looking for a Sportical height gas block? Quote Link to comment Share on other sites More sharing options...
survivalshop Posted November 20, 2016 Report Share Posted November 20, 2016 Are you talking about something like an A2 sight tower on a A2 AR 15 ? Or you talking about a Railed Gas block you can put a Front sight on ? Or are you talking about the flip down Gas Block Front sights ? I would say all the Flip up or A2 types will be std. hight to correspond to a Flat top , rail mounted Rear sight or A2 sight . Now the Railed Gas Block , may be a different story . Quote Link to comment Share on other sites More sharing options...
blue109 Posted November 20, 2016 Report Share Posted November 20, 2016 Is this an actual DPMS branded upper or a different brand? And if it's an off brand did it specify high or low rail. I ask because you said "sportical style" If it has that railed gas block that is lower than the top rail you might be screwed. YHM made a special front sight for those but I don't think they do anymore. Maybe DPMS. most people just replace them with a rail height gas block or a flip up sight gas block. If you have a DPMS upper, or a "low" height off brand upper, any AR15 height gas block rail/sight will be good to go. Quote Link to comment Share on other sites More sharing options...
Mr_Roboto Posted November 21, 2016 Author Report Share Posted November 21, 2016 (edited) Let me post some pics and measurements. It is an aftermarket upper, but I've looked at CMMG and they certainly did make this height among others. As far as I can tell DPMS has done 4 styles, a low, modified low (something like 60 thousandths difference) the Sportical height and an even taller height still. The height from bore center comes out to roughly 1.62 with the height from the lower mating surface to the top of the flange approx 2.37. As a point of reference an AR-15 flat top's rail height above bore center is 1.250. This means that you're talking .37 to make up. Looking at UTG's site (no pun intended) They have a 1.38 front as their standard and the "gas block" height is 1.66. That is .280. That still leaves me a full blown tenth too low, which may be serviceable with an aftermarket "tall" post or just adjustment depending on what range/velocity/whatever I calibrate to. PS:pardon the high precision measuring equipment. Edited November 21, 2016 by Mr_Roboto Quote Link to comment Share on other sites More sharing options...
blue109 Posted November 21, 2016 Report Share Posted November 21, 2016 (edited) There are 3 DPMS standards. The older DPMS height (DPMS HIGH) the newer height that they swapped to in 09 (DPMS LOW) which is the same height over bore as a AR15. you appear to have the 3rd option, the Target height upper. You are pretty much screwed if you want irons. I don't think anyone ever made a front sight that will line up with that one. DPMS made a quad rail that would match that reciever but it weighs alot and might be hard to find. Best option is to buy a stripped normal height upper, or just run the scope Edited November 21, 2016 by blue109 Quote Link to comment Share on other sites More sharing options...
Mr_Roboto Posted November 21, 2016 Author Report Share Posted November 21, 2016 Yeah, I'm definitely getting that vibe out of this deal. I'm getting the idea that it likely used its own PN for the gas block, and that without such a gas block I'm probably not getting much to align. Quote Link to comment Share on other sites More sharing options...
survivalshop Posted November 21, 2016 Report Share Posted November 21, 2016 Yep , Blue109 is correct , you have the Bastard of DPMS Rail heights . Quote Link to comment Share on other sites More sharing options...
blue109 Posted November 21, 2016 Report Share Posted November 21, 2016 (edited) My first 308 was one of those. I considered a ton of options to make it into something I liked, but in the end i just sold the whole upper and built one exactly how I wanted it. Unless you are running a high power optic with a huge objective, there is no advantage to that upper. There is an aero upper for $150 over in the classifieds....just sayin ;) Edited November 21, 2016 by blue109 Quote Link to comment Share on other sites More sharing options...
blue109 Posted November 21, 2016 Report Share Posted November 21, 2016 Bang http://www.jsesurplus.com/DPMS308A3FlatTopUpperStripped-BLACKFRIDAY2016.aspx?utm_source=Black+Friday+AR+Parts+ETC+112116&utm_campaign=JSE+Black+Friday+Sale+2016+-+AR+Parts+Etc&utm_medium=email Quote Link to comment Share on other sites More sharing options...
survivalshop Posted November 22, 2016 Report Share Posted November 22, 2016 There's a deal ! Quote Link to comment Share on other sites More sharing options...
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