Bad threads - Stern Defense SD FH45 MOD1 Muzzle Device

I was really looking forward to using this on my new .45 carbine. When I went to install it the threads were miss tapped or had a bur on them. I checked the thread pitch on the muzzle devise and the barrel, they both matched. I contacted Optics Planet and the returned it without hesitation. I will be ordering the CMMG zeroed. I want to use the gun in a match but do not want to take a chase on bad threads again. Really like the look, but it didn't work out.