I need some dimensions...

[98Z5V]

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:

[Matt.Cross]

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.

[willbird]

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

 

[98Z5V]

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...

[Merle]

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. 

[98Z5V]

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

[Merle]

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. 

[willbird]

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

[Merle]

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.

[98Z5V]

19 hours ago, Merle said:

That's the pic I used on my gay porn resume. 

HAAAAAAAAAAAAAAAAAAHAHAHAHAAAAAA!!!!!   

[willbird]

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

[DNP]

I'm glad I quit the hard drugs. A thread about threads would have made my head explode more than a double $&@!ing rainbow. 

[Matt.Cross]

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....

[DNP]

Aw nuts!  I should have seen it turning this way. We could go round and round all day. 

[Matt.Cross]

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...

[DNP]

Sorry to screw up your thread. We'll try to keep things tighter from here out. 

Edited December 17, 2018 by DNP

[DNP]

It was a fairly revolutionary thought though. 

[sketch]

thats a round about way to screw this thread. kinda knarled.

Edited December 17, 2018 by sketch

[Matt.Cross]

Makes a man want to pitch a fit, the way this thread has taken a turn for the worse...

[DNP]

I'm just gonna back this one out slowly. I hope we haven't crossed anyone. 

[sketch]

hope he can take the heat if we really break loose!

[Boot_Scraper]

Gall-eey fellas, ya'll really stripped this thread of all it's 'tegrity.

 

[DNP]

I'll seize if I can get someone from the compound to keep from locking this up. 

Edited December 17, 2018 by DNP

[Merle]

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

[98Z5V]

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.