The dimpling on my melonited barrel does not match my YHM set screw gas block. I bought this barrel. I called them about which gas block was supposed to fit and they stated  that they were surplus barrels they purchased and not sure who they bought them from but they might be from Smith and Wesson.  First question is has anyone bought this barrel and know which gas block works? Or, does anyone know which clamp on gas block fits under the UTG pro super slim hand guard. Thanks.

I have the same set up exactly. The Yhm fit mine the dimple closest to the muzzle may have been a hair off but it seemed to tighten up. If yours is that far off you could redimple the barrel. But I would think the Yhm clamp on would fit the profile looks about the same as the set screw. http://palmettostatearmory.com/index.php/catalog/product/view/id/8943/category/351/. If you want I will pull mine apart and see how much clearance there is

SLR fits. KIES Adjustable does not.

I bought mine when Red Barn had a supper low price so I jumped on it. I think the low price at the time was not only they were leftovers from a run by a barrel maker but also because there were some discrepancies in the placement of the dimples and maybe some other minor stuff. I went with a clamp-on so I didn't have to worry about the dimples. I believe any clamp-on low profile gas block will work with the UTG pro super slim.. The one that "boxcutter77" showed would be good but at the time I think it's out of stock but I believe there are others that would also be good. You know there will be more people coming along to give you info on good low profile blocks to use.

edit to add: This looks like the same low profile gas block but sold by a different company. http://www.opticsplanet.com/yankee-hill-machine-low-profile-gas-block-with-pinch-screw-mounting-yhm-9384.html?utm_source=google&utm_medium=cpc&utm_campaign=plusbox-beta&gclid=CNiW_-aSicECFXAV7AodRAEAqQ