With the original -M gas block (the one that adjusts with a dial on the SIDE of the gas block) it's overgassed seriously. Like fling brass 60+ feet and ding the case rim such that it now protrudes into the extractor groove overgassed.
I'll be happy to experiment with the new gas block, when I can get one.
Until then though, I'm not running my -M suppressed any more. I've got for-real numbers with what I shot and recorded at the time - I actually measured out the distances I was getting with the brass using different gas settings, etc - if you want them.
Do you really think we want laws to be observed? We want them broken. There's no way to rule innocent men. The only power any government has is the power to crack down on criminals. When there aren't enough criminals, one makes them. One declares so many things to be crimes that it becomes impossible for men to live without breaking laws. Who wants law-abiding citizens? Pass the kind of laws that can’t be observed, enforced, or objectively interpreted - and you create a nation of law-breakers.
New to the forum and it seems like if I purchase a new 2017 XCR-M or L I will have an excellent rifle due to your loyalty and "test dumbness". As a future customer I thank you all!
"Necessity is the plea for every infringement of human liberty. It is the argument of tyrants; the creed of slaves."-William Pitt the Younger
I haven't tried a Thunderbeast on my -M yet. I've only used the OSS BPR4/SRM6, which simply is not a fair evaluation for gas pressure. The OSS costs more than the rifle, so not a typical option for most folks. That said, it works very well with the OSS!
"Don't Tread On Me!"
-- (reiterated without permission) Rich Hornay