98Z5V Posted December 14, 2018 Report Share Posted December 14, 2018 Merle 308 contacted me today about a spec that I can't get right now. Anybody have the diameter of a stripped 308 upper, at the threads? Not inside the threads, flat part of caliper on the threads... I need someone to measure this. I don't have any stripped 308 uppers right now, and it would suck to take a gun apart. I need this diameter: Quote Link to comment Share on other sites More sharing options...
Matt.Cross Posted December 14, 2018 Report Share Posted December 14, 2018 38 minutes ago, 98Z5V said: Merle 308 contacted me today about a spec that I can't get right now. Anybody have the diameter of a stripped 308 upper, at the threads? Not inside the threads, flat part of caliper on the threads... I need someone to measure this. I don't have any stripped 308 uppers right now, and it would suck to take a gun apart. I need this diameter: If I don't forget it, I'll get that tomorrow. Quote Link to comment Share on other sites More sharing options...
willbird Posted December 14, 2018 Report Share Posted December 14, 2018 DPMS pattern is a 1-7/16 - 16TPI thread, my PSA Gen I upper measures 1.430 over top of the threads....about what I'd expect. Found this on the forum https://308ar.com/ar-10-308-ar-compatibility-reference-guide/ The barrel nut and upper receiver threads follow along the same lines as the Quote Link to comment Share on other sites More sharing options...
98Z5V Posted December 14, 2018 Author Report Share Posted December 14, 2018 16 minutes ago, willbird said: my PSA Gen I upper measures 1.430 over top of the threads That's what I was afraid of... Quote Link to comment Share on other sites More sharing options...
Merle Posted December 14, 2018 Report Share Posted December 14, 2018 Thanks for checking for me guys. I am taking this up with the manufacturer of the upper. I also had problems with their lower as well having out of spec threads for the receiver extension. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted December 14, 2018 Author Report Share Posted December 14, 2018 (edited) I like the profile pic, brother - looks just like you... I need to get you down here to shoot, man... Edited December 14, 2018 by 98Z5V Quote Link to comment Share on other sites More sharing options...
Merle Posted December 14, 2018 Report Share Posted December 14, 2018 2 minutes ago, 98Z5V said: I like the profile pic, brother - looks just like you... I need to get you down here to shoot, man... That's the pic I used on my gay porn resume. Quote Link to comment Share on other sites More sharing options...
willbird Posted December 14, 2018 Report Share Posted December 14, 2018 Just some general errata about threads. The lead is 1" / threads per inch, so in the case of a 1-7/16-16 thread the "tap drill size" we would typically use is the major dia minus the lead. So again for 1-7/16-16 we would use a 1.375 tap drill. metric threads are specified with the lead typically, so for a M6 x 1.0(this is the lead) we would use a 5MM tap drill. So if you have sharp topped threads at 1.400 major dia...the nut will be sloppy as %^$#@ probably ?? Bill Quote Link to comment Share on other sites More sharing options...
Merle Posted December 15, 2018 Report Share Posted December 15, 2018 5 hours ago, willbird said: Just some general errata about threads. The lead is 1" / threads per inch, so in the case of a 1-7/16-16 thread the "tap drill size" we would typically use is the major dia minus the lead. So again for 1-7/16-16 we would use a 1.375 tap drill. metric threads are specified with the lead typically, so for a M6 x 1.0(this is the lead) we would use a 5MM tap drill. So if you have sharp topped threads at 1.400 major dia...the nut will be sloppy as %^$#@ probably ?? Bill The threads on the upper receiver fit into the barrel nut like the proverbial hotdog down a hallway. So yeah it's pretty sloppy. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted December 15, 2018 Author Report Share Posted December 15, 2018 19 hours ago, Merle said: That's the pic I used on my gay porn resume. HAAAAAAAAAAAAAAAAAAHAHAHAHAAAAAA!!!!! Quote Link to comment Share on other sites More sharing options...
willbird Posted December 15, 2018 Report Share Posted December 15, 2018 14 hours ago, Merle said: The threads on the upper receiver fit into the barrel nut like the proverbial hotdog down a hallway. So yeah it's pretty sloppy. I kind of lost myself in the dissertation about tap drill sizes, but you can use that math to make sure the barrel nut is on spec. major dia - the lead of the thread will give you minor dia for close to 80% thread. Bill Quote Link to comment Share on other sites More sharing options...
DNP Posted December 16, 2018 Report Share Posted December 16, 2018 I'm glad I quit the hard drugs. A thread about threads would have made my head explode more than a double $&@!ing rainbow. Quote Link to comment Share on other sites More sharing options...
Matt.Cross Posted December 16, 2018 Report Share Posted December 16, 2018 9 hours ago, DNP said: I'm glad I quit the hard drugs. A thread about threads would have made my head explode more than a double $&@!ing rainbow. Nothing screws with my head like threads.... Quote Link to comment Share on other sites More sharing options...
DNP Posted December 17, 2018 Report Share Posted December 17, 2018 Aw nuts! I should have seen it turning this way. We could go round and round all day. Quote Link to comment Share on other sites More sharing options...
Matt.Cross Posted December 17, 2018 Report Share Posted December 17, 2018 18 minutes ago, DNP said: Aw nuts! I should have seen it turning this way. We could go round and round all day. That sounds fastenating... Quote Link to comment Share on other sites More sharing options...
DNP Posted December 17, 2018 Report Share Posted December 17, 2018 (edited) Sorry to screw up your thread. We'll try to keep things tighter from here out. Edited December 17, 2018 by DNP Quote Link to comment Share on other sites More sharing options...
DNP Posted December 17, 2018 Report Share Posted December 17, 2018 It was a fairly revolutionary thought though. Quote Link to comment Share on other sites More sharing options...
sketch Posted December 17, 2018 Report Share Posted December 17, 2018 (edited) thats a round about way to screw this thread. kinda knarled. Edited December 17, 2018 by sketch Quote Link to comment Share on other sites More sharing options...
Matt.Cross Posted December 17, 2018 Report Share Posted December 17, 2018 Makes a man want to pitch a fit, the way this thread has taken a turn for the worse... Quote Link to comment Share on other sites More sharing options...
DNP Posted December 17, 2018 Report Share Posted December 17, 2018 I'm just gonna back this one out slowly. I hope we haven't crossed anyone. Quote Link to comment Share on other sites More sharing options...
sketch Posted December 17, 2018 Report Share Posted December 17, 2018 hope he can take the heat if we really break loose! Quote Link to comment Share on other sites More sharing options...
Boot_Scraper Posted December 17, 2018 Report Share Posted December 17, 2018 Gall-eey fellas, ya'll really stripped this thread of all it's 'tegrity. Quote Link to comment Share on other sites More sharing options...
DNP Posted December 17, 2018 Report Share Posted December 17, 2018 (edited) I'll seize if I can get someone from the compound to keep from locking this up. Edited December 17, 2018 by DNP Quote Link to comment Share on other sites More sharing options...
Merle Posted December 27, 2018 Report Share Posted December 27, 2018 (edited) Well just got word from the manufacturer that their upper and lower was in spec but they will issue a refund if I'd like. I guess a receiver extension is supposed to fit so loose that you can damn near pull it out when it's threaded in to their lower and a barrel nut that moves up and down .030" when threaded on to their upper is considered in spec in their part of the country. So the search is on again for a SR-25 style upper and lower. Edited December 27, 2018 by Merle Quote Link to comment Share on other sites More sharing options...
98Z5V Posted December 27, 2018 Author Report Share Posted December 27, 2018 40 minutes ago, Merle said: Well just got word from the manufacturer that their upper and lower was in spec but they will issue a refund if I'd like. What spec, brother? They're so full of it, it's not even funny. I'd like to see them build up something with it. Quote Link to comment Share on other sites More sharing options...
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