Uzi
.308 Win
Some of them sure do look interesting on ebay. Almost like gemtech suppressor baffles without the threaded sleeve, just sayin'
Also, Sig made something like this labeled as a muzzle brake years ago. Their version did have the threads added, but the muzzle brake alone was deemed a suppressor.
5/8” - 24 Muzzle Brake (Skeletonized) | eBay
And there are a lot more styles were that came from, copying various types of one piece baffle inserts.

5/8” - 24 Muzzle Brake (Skeletonized) | eBay



And there are a lot more styles were that came from, copying various types of one piece baffle inserts.