Ok, so I am finding myself in a bit of a conundrum. I recently got a Tantal parts kit and everything has been delivered to my gunsmith. The problem is that the gas block / front sight combo I purchased is too large. The diameter of the gas journal on the green mountain tantal barrel that came with the kit is .581 (14.75mm), the inner diameter of the front sight gas block is .591 (15mm) a total difference of .01 (.25mm). My question is this, I have read several accounts of builders having success knurling the underside of the barrel to make up for oversized/undersized gas blocks/journals. I saw a few suggestions even saying to seal the ends with high temp silver solder and even knurling the entire journal and covering that with silver solder then turning it to size like that. My question really is if any of these techniques really work and if so can that make up the size difference between the gas block and gas journal? (it is probably worth noting that the barrel does not have the gas port drilled yet)

Just one thought...  Solder is relatively soft.  I don't know if I'd trust it around any area where temperatures could soften it further.

I know there are types of silver solder that is rated up to 1400F, high enough that the AFT considers it a way to permanently attach a muzzle device