Looking at building a F/TR rifle in 223 mostly looking for a practice rifle and shooting to 600. But thought about shooting to 1k and was looking at a 1-6.5 twist barrel that was available now. Question is would it give a much shorter barrel life than a 1-8 or 1-7. Not really planning on shooting the 90's which require this twist. Also will I see negative impact on shooting bullets in the 70-80 grain range with this fast a twist. I was looking to build on a 1-8 twist but this barrel is available now versus a 6 month plus lead time on a 1-8. Barrel is a from a premium manufacturer. Would appreciate your thoughts.