jtallen83 Posted September 6, 2018 Report Share Posted September 6, 2018 Wanted a DI gun to replace my Sig P716 jam-o-matic. When I saw CDNN clearing out the 12.5 inch Sig barrels used for the P716 I figured what the hell. The Sig parts are mostly DPMS compatible and CDNN had a bunch of them including the bolt. Gas tube length was the only big difference I had to deal with. Parts list; Aero M5 blem receiver set and 10 inch rail, Tactical Grey Cerakote Sig 716 12.5 inch barrel, chrome lined, .073 gas port D. Wilson Carrier and firing pin with a Sig 716 dual ejector bolt. Cotton Arms Adjustable Gas Block 11 inch gas tube custom made by White Oak Armament. Vltor RE-10/A5SR: A5 Receiver Extension (had to add 50 cents) PWS MOD2 Carbine Buffer - H3 5.5 oz Tubbs Flat Wire Spring LaRue MBT trigger DPMS upper parts Aero LPK Magpul MOE-K2+ Pistol Grip PSA branded SB3 adjustable pistol brace This build comes in just over 1 pound less than the P716 at about 8.5 pounds. Much better balance than the 716 and more rail length to work with. The "brace" being adjustable and using a carbine extension tube is the schit! I was thinking the port would be small but no way, I had to crank the gas block way down and it isn't broke in yet. 25 rounds down the pipe and no malfunction except the two fired at the tightest setting of the gas block, ejected but did not lock back. Worked with Lancer and Magpul mags. The bore has to be dead on concentric with the threads, best looking suppressor alignment I have seen to date with the gauge looking dead nuts center. Hope to get the PA 4x16 on it this weekend and see what it will group as well as check out how it reacts to some heat. Brass ejects about 3-4 o'clock with no suppressor, no swipe, pretty light primer strike; With the suppressor they land about 1 o"clock and show a little ejector smear; Quote Link to comment Share on other sites More sharing options...
98Z5V Posted September 6, 2018 Report Share Posted September 6, 2018 HOT DAMN, BROTHER!!! It's running WELL!!! Quote Link to comment Share on other sites More sharing options...
Rsquared Posted September 9, 2018 Report Share Posted September 9, 2018 That thing looks SWEET JT. But everybody knows that I'm an SBR fanboy. (yes....I see that it's a "pistol" build). Quote Link to comment Share on other sites More sharing options...
jtallen83 Posted October 3, 2018 Author Report Share Posted October 3, 2018 Finding the Lancer mags not so reliable in this rifle pistol. Ran 50 rounds of M80 ball today, Federal and some Austrian stuff. When using the lancer mags the bolt catch engages the carrier and not the bolt, when I cycle it by hand it grabs the bolt. Ran from high to low on the gas settings with no changes till it is choked down and doesn't cycle. With P-mags it grabs the bolt 100% unless the gas is choked way down. On occasion it will drop the Lancer mag out on the last round, I was going to swap the mag catch for an Armalite A model catch but with the bolt catch issue it looks like I will just stick to P-mags. Possibly I have an out of spec Lancer mag. Accuracy was nothing great but didn't expect much with M-80 ball and using an early PA 4x16 Mil Dot scope that I have never gotten good results from, has a VERY tight eye box, very tight eye relief, and a funky parallax adjustment. Hoping to pick up a more permanent optic on holiday sales coming up. Quote Link to comment Share on other sites More sharing options...
willbird Posted December 21, 2018 Report Share Posted December 21, 2018 So what is the story on the Sig barrels ?? What does one need to to to use one in AR 308 ?? Kind of looking at the Aero upper/lower myself. "Only fits Sig Sauer 716 rifles. Will not work with any SR25 or AR10 platform." Quote Link to comment Share on other sites More sharing options...
98Z5V Posted December 21, 2018 Report Share Posted December 21, 2018 Custom gas tube. That's about it. Quote Link to comment Share on other sites More sharing options...
willbird Posted December 21, 2018 Report Share Posted December 21, 2018 Forgot to say nice build :-). But back to the Sig bbl, does it require the sig bolt to match ?? The custom gas is not a super big deal I suppose. Bill Quote Link to comment Share on other sites More sharing options...
jtallen83 Posted December 21, 2018 Author Report Share Posted December 21, 2018 (edited) On 12/21/2018 at 7:22 AM, willbird said: Forgot to say nice build :-). But back to the Sig bbl, does it require the sig bolt to match ?? The custom gas is not a super big deal I suppose. Bill I am running the Sig bolt in it but it headspaces and runs on a D Wilson 308 bolt as well. Gas block hangs over the step by a bit to line up the ports so if it were one of those blocks that has an opening in the clamping surface it may not seat well. An SLR gas block jig was a big help getting the dimples in the correct place. Just bought a second barrel when they had them for $49.99, DPMS style bolt headspaces on it as well. Don't forget to grab a 716 bolt catch as well, works in everything I have tried it in. Edit: Just had a Sig 716 bolt catch not fit in an Aero receiver I just got, odds are just a little thinning and it would have worked though. Edited October 4, 2019 by jtallen83 Quote Link to comment Share on other sites More sharing options...
willbird Posted December 21, 2018 Report Share Posted December 21, 2018 Nice info :-). What did the gas tube end up costing for a custom ?? Bill Quote Link to comment Share on other sites More sharing options...
jtallen83 Posted December 21, 2018 Author Report Share Posted December 21, 2018 1 hour ago, willbird said: What did the gas tube end up costing for a custom ?? Right around $40, obviously custom with the polish and the very well done bends and ends. Mine was 11 inches but I highly recommend you measure with your gas block in place to be sure. Quote Link to comment Share on other sites More sharing options...
willbird Posted December 21, 2018 Report Share Posted December 21, 2018 Yes it is a good exercise to measure. I want to draw the whole assembly up on cad as a cross section to show the actual interface with the BCG. Quote Link to comment Share on other sites More sharing options...
308kiwi Posted December 21, 2018 Report Share Posted December 21, 2018 NICE You forgot to tell us what suppressor you are running.......... Quote Link to comment Share on other sites More sharing options...
jtallen83 Posted December 21, 2018 Author Report Share Posted December 21, 2018 24 minutes ago, 308kiwi said: NICE You forgot to tell us what suppressor you are running.......... I have a couple AAC SDN-6's. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted December 22, 2018 Report Share Posted December 22, 2018 7 hours ago, jtallen83 said: I have a couple AAC SDN-6's. One is a reman, though... I still can't believe how they wrote that up, and completely took care of you. That's just badass. Quote Link to comment Share on other sites More sharing options...
jtallen83 Posted December 22, 2018 Author Report Share Posted December 22, 2018 29 minutes ago, 98Z5V said: One is a reman, though... Good as new! Quote Link to comment Share on other sites More sharing options...
98Z5V Posted December 22, 2018 Report Share Posted December 22, 2018 They are badass, brother. Completely. Quote Link to comment Share on other sites More sharing options...
RedRiverII Posted July 20, 2019 Report Share Posted July 20, 2019 Late to the party, but damn that's a beauty. Quote Link to comment Share on other sites More sharing options...
Albroswift Posted August 20, 2019 Report Share Posted August 20, 2019 On 9/5/2018 at 6:11 PM, jtallen83 said: Wanted a DI gun to replace my Sig P716 jam-o-matic. When I saw CDNN clearing out the 12.5 inch Sig barrels used for the P716 I figured what the hell. The Sig parts are mostly DPMS compatible and CDNN had a bunch of them including the bolt. Gas tube length was the only big difference I had to deal with. Parts list; Aero M5 blem receiver set and 10 inch rail, Tactical Grey Cerakote Sig 716 12.5 inch barrel, chrome lined, .073 gas port D. Wilson Carrier and firing pin with a Sig 716 dual ejector bolt. Cotton Arms Adjustable Gas Block 11 inch gas tube custom made by White Oak Armament. Vltor RE-10/A5SR: A5 Receiver Extension (had to add 50 cents) PWS MOD2 Carbine Buffer - H3 5.5 oz Tubbs Flat Wire Spring LaRue MBT trigger DPMS upper parts Aero LPK Magpul MOE-K2+ Pistol Grip PSA branded SB3 adjustable pistol brace This build comes in just over 1 pound less than the P716 at about 8.5 pounds. Much better balance than the 716 and more rail length to work with. The "brace" being adjustable and using a carbine extension tube is the schit! I was thinking the port would be small but no way, I had to crank the gas block way down and it isn't broke in yet. 25 rounds down the pipe and no malfunction except the two fired at the tightest setting of the gas block, ejected but did not lock back. Worked with Lancer and Magpul mags. The bore has to be dead on concentric with the threads, best looking suppressor alignment I have seen to date with the gauge looking dead nuts center. Hope to get the PA 4x16 on it this weekend and see what it will group as well as check out how it reacts to some heat. Brass ejects about 3-4 o'clock with no suppressor, no swipe, pretty light primer strike; With the suppressor they land about 1 o"clock and show a little ejector smear; One question, Tubbs flat wire spring Did you use a 7-5/8" tube with the brace? Put mine together last night with the 7" tube that came with the brace and spring, completely compressed, would not allow BCG to catch on the bolt catch. Good 1/2" clearance without Tubbs spring, actually need 50 cents or so to clear the ears. Quote Link to comment Share on other sites More sharing options...
jtallen83 Posted August 20, 2019 Author Report Share Posted August 20, 2019 Just now, Albroswift said: One question, Tubbs flat wire spring Did you use a 7-5/8" tube with the brace? Put mine together last night with the 7" tube that came with the brace and spring, completely compressed, would not allow BCG to catch on the bolt catch. Good 1/2" clearance without Tubbs spring, actually need 50 cents or so to clear the ears. Yes, Vltor RE-10 is the same length as the Armalite AR-10 extension. I put the 50 cents in to get the bolt a little closer to the catch when all the way back, didn't want it slamming the catch to hard. I'm thinking I put a Tubbs spring in my Matrix build but I may be thinking of something else, did a bunch of buffer and spring combo changes when I got my suppressors. From the Tubbs video you should not be having that issue though, very curious to see what the deal is. Quote Link to comment Share on other sites More sharing options...
Albroswift Posted August 21, 2019 Report Share Posted August 21, 2019 7" tube, 5.8 oz 2-1/2" buffer. Put a 7-5/8" tube on it and a 3-1/4" buffer and a 1/8" hdpe spacer (didn't have 50 cents left) things look good. That Tubbs is a raskel to install that's for sure. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted August 21, 2019 Report Share Posted August 21, 2019 1 hour ago, Albroswift said: 7" tube, 5.8 oz 2-1/2" buffer. Put a 7-5/8" tube on it and a 3-1/4" buffer and a 1/8" hdpe spacer (didn't have 50 cents left) things look good. That Tubbs is a raskel to install that's for sure. Sounds like a Rock River LAR-8 buffer. Quote Link to comment Share on other sites More sharing options...
Albroswift Posted August 21, 2019 Report Share Posted August 21, 2019 I know I'm going to get a cussing here but I just turned a longer bumper out of HDPE for the 5.8 oz 2-1/2" KVP buffer. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted August 22, 2019 Report Share Posted August 22, 2019 15 hours ago, Albroswift said: I know I'm going to get a cussing here but I just turned a longer bumper out of HDPE for the 5.8 oz 2-1/2" KVP buffer. Hell no, man - That's pretty smart. Put up some pics of that weirdo sometime. Quote Link to comment Share on other sites More sharing options...
Albroswift Posted August 22, 2019 Report Share Posted August 22, 2019 nothing fancy Hey, the paper clip is working beautifully, multiple uploads at once Quote Link to comment Share on other sites More sharing options...
98Z5V Posted August 23, 2019 Report Share Posted August 23, 2019 3 hours ago, Albroswift said: Hey, the paper clip is working beautifully, multiple uploads at once That part has been cracked now - fixed. Any other issues, let it be known in this section: https://forum.308ar.com/forum/60-site-news-and-support/ Quote Link to comment Share on other sites More sharing options...
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