Well, as much as it pains me to revive this thread to say that it happened again, it does have a happy ending.
That's right, the Odin Works Tunable Gas Block that I received as a replacement for my Odin Works Adjustable Gas Block (because the Adjustable split in half...see the OP) has experienced the exact same catastrophic failure on the exact same gun, albeit under slightly different circumstances. I was told by Odin Works, after learning the hard way, that the Adjustable wasn't rated for pistol-length gas systems on high-pressure rounds like 5.56. To their credit, the product page does say this in big, bold letters. However, they said the Tunable is just the ticket for my application. Well, it was working great until yesterday when I combined a
Slide Fire stock with a SureFire 60-rd mag through my 10.5" SBR. After about 40 rds had blown off in simulated full-auto fire, the gas block split in half and the gas tube fell to the ground with the roll pin still embedded:
Needless to say, I was pretty disappointed, but I also knew I was probably pushing the limits with the bump firing. I have another Tunable block on my .300 BLK SBR, but I don't bump fire it and I only shoot subsonic rounds, and it's holding up just fine.
I called Odin Works today and spoke to a very friendly guy (didn't catch his name). Anyway, he apologized for the failure and offered to send me not only a replacement Tunable block (for use on a different build), but also a standard (non-tunable/adjustable) gas block for use on this SBR. He just said to go to their website and submit a RMA. Not even 30 minutes passed between the time I hit 'Submit' on the RMA and when I had an email in my Inbox saying "Odin Works has sent you a package."
I like their products, but I love their customer service. But that's definitely the last time I bump fire with their adjustable/tunable gas blocks.