With a .243 bore I would just chop it off and go 1/2-28. It's not expensive and will result in plenty of wall diameter and shoulder while addressing any concerns about indexing. I went this route on an x-bolt in .243 Win and it works great.
What's the barrel length? If it's 24" you'll end up with a pretty unwieldy, front heavy package after you add the suppressor. I cut my bolt guns 16-18" for standard chamberings and 20-21" for magnums. Worth the small drop in velocity.
