Ordered an Alexander Arms 6.5 Grendel and it only comes with a 9/16 threading. Where can I get a really good 9/16 to 5/8 adapter so I can attach my can. Looking for someplace in the DFW area. Thanks Better yet...is it ok to even do this with this rifle. I'm having people tell me it's fine and I'm having people tell me they wouldn't do it!