First 308 AR build and questions about Juggernaut's Rail

[sketch]

👍🇺🇸

[Belt Fed]

That's a fine looking rifle. you did good

[unforgiven]

Nice rifle you got going on brother 👍

[Rsquared]

Whoa, that's a nice lookin unit there Haewired. Good job my man. And yes, the UBR's add a little heft to these things. But if/when the rifle goes CLICK, you can swing that thing around and bludgeon the $hit outta somebody with it. Those stocks are rock solid.

[haewired]

 

[shooterrex]

Nice looking rifle. Glad it is running on for you.

[RedRiverII]

Nice job haewired,  best of luck.

[Belt Fed]

Don't know if you hunt, but the rifle looks ready to go. nice job.

[haewired]

I’ll add some more comments later but here’s a synopsis 

[Armed Eye Doc]

Nice job.. I always like it when a new rifle functions the way it is supposed to.

[sketch]

good report brother! 🍻

[haewired]

Ok, I put 100 rounds through my rifle yesterday and took my rifle apart for cleaning and inspection.  What did I find?  My lower failed by cracking and stripping threads at the buffer tube.  You'll see in the pictures that the receiver extension ring threads are stripped out.  That explains why I had a misfire because the buffer retention pin broke loose at the end of the day.  Next you'll see a crack on the right side of the receiver starting from the top of the receiver above the take down pin, propagating down past the takedown pin and working its way to the handle.

I kinda expected this, but I had some hope that this polymer receiver would be the exception.  It was fun to build and I wanted the experience to make a functional 80% lower.  As far as I'm concerned it's a paper weight now.  I'm glad I didn't have a catastrophic failure while operating the rifle, and I'm happier to have learned about this experience and share it with you all.  I plan on posting another thread on this warning about this lower and any other poly lowers with a round count of over 100.  If any of you have a poly lower with a round count over 100, I highly suggest you inspect your lower.

Well, it's a good thing I ordered a "Raw" 80% lower from Juggernaut Tactical.  There's my next project!

[SimonSays]

Well, that just sucks. 

You had a nice looking rifle and spent a lot of time on it. 

Yep, that sucks. 

🤬

[Armed Eye Doc]

I have to agree.  That sucks.  

[haewired]

It was a fun experiment.  I’m looking forward to getting my next Aluminum lower up and running!

[sketch]

that sucks balls! rebuild and repeat!

Edited May 21, 2019 by sketch
shits of course..

[willbird]

Yea that totally sucks :-(, after I read the first post I was googling the part and looking at it on their web page. Did they offer to replace it ??

I know with my AP Sig shorty there is a HUGE difference in recoil impulse between no brake and a Surefire brake, and that all takes place within the barrel where the recoil is created, BUT I have no idea what the actual recoil looks like on paper. The same recoil impulse (maybe 80% of it ?) must be created as the bullet goes down the barrel, then it is countered by the brake. I seem to recall seeing that something like 20% of recoil is gas jet effect after the bullet has left the barrel ?? There are some videos out on the net of 50 bmg stuff showing the rifle moving rearward, then the brake pulling it back forward on those cases, can eat up some scopes that take "normal" recoil in stride just fine.

Bill