Gemtech HALO.
BTW, the idea of dumping full auto 556 through it to 'clean out' 22LR doesn't work...
For a hard use rifle can, I would avoid titanium for sure. I have seen more damaged Ti cans than anything else. Mostly from people using them on FA
I've used 3-5 rounds of semi and/or full auto fired 5.56 rounds to clear the 5.56 barrel port many times on several different 5.56 barrels without any problem. But I've only shot, at the most, 250 or so rounds of .22LR (both semi and full auto) before performing the 5.56 ammo clearing shooting. I have read of 5.56 gas ports getting so badly contamination filled by high round .22LR use that the gun had to be manually cocked to fire 5.56 rounds until the gas block was taken off and the port cleaned.goes the same for clearing out a gas tube, I had one clog up from shooting a .22 FA conversion and thought a few hot rounds of 556 would be enough to blow it out, it sure did, right out the top of the hand guard, luckily most of it stuck in the A2 front sight and no one got hurt.
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The story above is a good reason to have a dedicated 22LR upper + suppressor...