Where did you place your support hand while firing?4.5" 5.56 barrel under a 10" junk ass amazon rail. Chris and I probably shot 30 rounds through it. It did fine. Not sure how it would have held up to prolonged use or adding a muzzle brake.
I wouldn't recommend it solely due to safety concerns. You'd have to be hyper aware of hand placement at all times. Plus, the blast, hot gasses, etc would eventually start to eat away at the aluminum. And you're going to have a gun covered in burnt powder. If you used any type of brake, it would blow the rail apart sooner or later. Probably sooner.