Albroswift Posted June 15, 2021 Report Share Posted June 15, 2021 Rounding up parts for next build, want to mount a carry handle on the "low profile" flat top, and front sight on a picatinny gas block. Cutting the shoulder back on my last sig 12.5" barrel to work with a 6" Armalite handguard and the delta ring set @shooterrex donated. Kind of an XM177E2 look in .308. After spending hour or three on google, more questions then answers. #1; How do I get the heights of the sights correct? #2 How to match up a gas block, front sight with a picatinny carry handle? #3 Who makes a 308 low profile height picatinny gas block? Really like one that's adjustable, but I can deal with that either way. Or a shorter rail/ taller sight? Holy moly... Other option would be the fixed front sight, got plenty of journal length. I plan on moving the port anyway. Still have to match the height. Quote Link to comment Share on other sites More sharing options...
unforgiven Posted June 15, 2021 Report Share Posted June 15, 2021 That is going to be sharp brother Quote Link to comment Share on other sites More sharing options...
392heminut Posted June 15, 2021 Report Share Posted June 15, 2021 This is going to be a pretty cool build once you get it all sorted out! How are you planing on securing the front handguard cap in place? Quote Link to comment Share on other sites More sharing options...
Albroswift Posted June 15, 2021 Author Report Share Posted June 15, 2021 14 minutes ago, 392heminut said: How are you planing on securing the front handguard cap in place If the new gas block doesn't shove up tight against it I can turn a spacer. Gas block in photo doesn't have any thing to do with the build. Probably have to drill a new port or reverse a gas block for everything to fit up. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted June 15, 2021 Report Share Posted June 15, 2021 1 hour ago, Albroswift said: #3 Who makes a 308 low profile height picatinny gas block? Really like one that's adjustable, but I can deal with that either way. Or a shorter rail/ taller sight? Holy moly... JD Machine used to make that, and @DNP has one. JD Machine is gone now, though. Gonna be a tough hunt, for that, I'll try to come up with more ideas. Find a .308AR carry handle yet? That's gonna be hard to find, too... Quote Link to comment Share on other sites More sharing options...
jtallen83 Posted June 15, 2021 Report Share Posted June 15, 2021 1 hour ago, Albroswift said: #2 How to match up a gas block, front sight with a picatinny carry handle? And now I know. Back a good while they had some jigs for lining up the front sights with the carry handle listed on the clearance section of the Armalite site. Never looked to close just remember thinking, Why would someone need this? Now I know but that ain't gonna help you. Quote Link to comment Share on other sites More sharing options...
jtallen83 Posted June 15, 2021 Report Share Posted June 15, 2021 8 minutes ago, 98Z5V said: Find a .308AR carry handle yet? I was second place bidder last one I saw on ebay, maybe two months ago, $215 would not buy it. Quote Link to comment Share on other sites More sharing options...
Albroswift Posted June 15, 2021 Author Report Share Posted June 15, 2021 23 minutes ago, 98Z5V said: Find a .308AR carry handle yet? That's gonna be hard to find, too... I was thinking AR15 carry handle, but now that you mention it... Got lots of projects, don't need everything right away. I'll keep my eyes open, and bid $1.00 more then @jtallen83 Quote Link to comment Share on other sites More sharing options...
Albroswift Posted June 15, 2021 Author Report Share Posted June 15, 2021 Never heard of these guys. http://www.cert-tactical.com/shop/index.php?main_page=index&manufacturers_id=25 RRA also has them but cant tell if large or small platform https://www.rockriverarms.com/index.cfm?fuseaction=category.display&category_ID=1733 Quote Link to comment Share on other sites More sharing options...
98Z5V Posted June 15, 2021 Report Share Posted June 15, 2021 (edited) The RRA stuff is AR15, I have one of those, in the NM flavor. Cert lists a couple good parts for you. http://www.cert-tactical.com/shop/index.php?main_page=product_info&cPath=25&products_id=23078 http://www.cert-tactical.com/shop/index.php?main_page=product_info&cPath=25&products_id=23077 Just gotta find the Armalite AR-10 pic gas block, and you're set. Edited June 15, 2021 by 98Z5V Quote Link to comment Share on other sites More sharing options...
jtallen83 Posted June 15, 2021 Report Share Posted June 15, 2021 38 minutes ago, Albroswift said: Never heard of these guys. http://www.cert-tactical.com/shop/index.php?main_page=index&manufacturers_id=25 I can't get past shipping on checkout, says to contact the store, I will be shocked if they actually have these. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted June 15, 2021 Report Share Posted June 15, 2021 (edited) @Albroswift, gas block solved. PRI makes it. https://www.midwayusa.com/product/2367115050 Edited June 15, 2021 by 98Z5V Quote Link to comment Share on other sites More sharing options...
Albroswift Posted June 15, 2021 Author Report Share Posted June 15, 2021 (edited) 6 hours ago, jtallen83 said: I can't get past shipping on checkout, says to contact the store, I will be shocked if they actually have these. Something is fishy, they have ammo for pre apocalypse pricing and half of their pages have instructions for the web builder on them. Sent them contact form. @98Z5V Top rail is the same height as an Armalite 308 receiver. Is Armalite top rail same as DPMS low? Edited June 15, 2021 by Albroswift Quote Link to comment Share on other sites More sharing options...
Albroswift Posted June 15, 2021 Author Report Share Posted June 15, 2021 Cert-tactical contact form and email come back undeliverable. Too good to be true. Luckily their checkout doesn't work. Quote Link to comment Share on other sites More sharing options...
Albroswift Posted June 16, 2021 Author Report Share Posted June 16, 2021 This RRA is for their LAR-8 https://www.rockriverarms.com/index.cfm?fuseaction=category.display&category_ID=1514 Another forum mentioned needing a diviot in the upper directly under the sight adjustment stud. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted June 16, 2021 Report Share Posted June 16, 2021 (edited) 16 hours ago, Albroswift said: @98Z5V Top rail is the same height as an Armalite 308 receiver. Is Armalite top rail same as DPMS low? Yes, it is. Barrel nut threading is different, between the two (DPMS LR-308 and Armalite AR-10), but the rail heights are identical. Barrel nuts are not interchangeable, but the rails are, give the same barrel nut lockup/mounting. DPMS LR-308 is 16 TPI, and Armalite AR-10 is 18 TPI. Edited June 16, 2021 by 98Z5V Quote Link to comment Share on other sites More sharing options...
Albroswift Posted June 16, 2021 Author Report Share Posted June 16, 2021 7 hours ago, 98Z5V said: Yes, it is. Think I'm going to get the LAR-8 carry handle. They mention their front sight is for a low railed block, digging into that a little further. Quote Link to comment Share on other sites More sharing options...
Albroswift Posted June 18, 2021 Author Report Share Posted June 18, 2021 From RRA: Their railed front sight gas block for their front sight: From the center bore to the rail will be .975” Same Rail Height gas block: Same plane is center bore to the top of rail 1.215” I measured 2 of my uppers and the rail planes out about 1.250 +/- from center of bore so if tech support is correct the RRA 308 upper is .035 lower then a low profile DPMS. To use the LAR-8 carry handle and front sight I would need a .940 +/- off the center of bore gas block. RRA DETACHABLE FRONT SIGHT ITEM #: AR0160 FOR LOW GAS BLOCK HEIGHT RAIL MOUNTING. 6061 ALUMINUM. RRA LAR-8 A2 CARRY HANDLE ASSEMBLY ITEM #: 308A0052CASY WITH A2 REAR SIGHT. Quote Link to comment Share on other sites More sharing options...
Tack14 Posted June 18, 2021 Report Share Posted June 18, 2021 BRD Engineering makes jigs and fixtures related to front sight post barrel drilling and alignment for AR15 and 308 too. https://brdengineering.com/t/front-sight-base-tools I was looking into this kind of thing for an AR15 build and ended up letting John Thomas at Retro Arms Works do the front sight base pinning for me, John did an excellent job with fast turn around. They also sell a set of alignment rods in carbine, rifle, and mid lengths, I could surely be wrong but these ought to work with .308 too? Not sure but the center rod is adjustable so seems like it would probably be able to work. Quote Link to comment Share on other sites More sharing options...
Rsquared Posted June 18, 2021 Report Share Posted June 18, 2021 I have an Armalite pic rail block that you might be able to use Albroswift. Though, if I remember, it was lower than the pic rail on the receiver. When I get back to my place I'll dig it out of my parts box. It was never used. It came on an Armalite barrel I used for a generic carbine that I built years ago. I'll take a picture so you can see if it'll be useful or not. Quote Link to comment Share on other sites More sharing options...
Albroswift Posted June 18, 2021 Author Report Share Posted June 18, 2021 1 hour ago, Rsquared said: was lower than the pic rail on the receiver. For the big front sight, don't want rail height. Need one lower then receiver rail so yours might be right. My math says .940 from center of bore, so top of .750" journal .565 +/- .930 is pretty common it looks like. Quote Link to comment Share on other sites More sharing options...
Albroswift Posted June 18, 2021 Author Report Share Posted June 18, 2021 @Tack14 Good stuff... I think I have aligning it figured out, rotary indexer and the mill I should get some good accuracy using the axis of the bore and the alignment pin. Can always adjust a little bit after initial setup, most of these blocks look like clamp on. Quote Link to comment Share on other sites More sharing options...
Rsquared Posted June 19, 2021 Report Share Posted June 19, 2021 Sorry brother. I've been dealing with some on-going health issues with my 81 year old mother. By the time I got back home last night. I completely forgot about this. Anyway, here's a couple pics of the Armalite block that I have. If you think that it'll work, just give me a yell, PM me your address and it's yours. Quote Link to comment Share on other sites More sharing options...
jtallen83 Posted June 20, 2021 Report Share Posted June 20, 2021 I was just going to post up some pics that look very similar to yours. Quote Link to comment Share on other sites More sharing options...
Albroswift Posted June 20, 2021 Author Report Share Posted June 20, 2021 10 hours ago, Rsquared said: Sorry brother. I've been dealing with some on-going health issues with my 81 year old mother. By the time I got back home last night. I completely forgot about this. Anyway, here's a couple pics of the Armalite block that I have. If you think that it'll work, just give me a yell, PM me your address and it's yours. 0.545 is within .005 of what I came up with, perfect! I'll PM you. Quote Link to comment Share on other sites More sharing options...
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