Effect of freebore length on 260 AI and bullet selection (CEB anyone?)


Well-Known Member
Oct 2, 2014
Dayton Ohio
Hi guys,

So I am seriously looking at a Criterion barrel in 260 AI for my savage, and I see they have 2 versions of the AI chamber, a standard and a match. I asked them what the difference was and they sent me reamer prints and said the most significant difference is the freebore length: .098" on the standard and .160 on the match. I sent a reply back asking them what advantage the longer freebore has, but I figured I'd ask here too. Can someone shed some light on this for me? Freebore is one thing I haven't read into much yet. I'm assuming it has some effect on how you seat bullets and how they engage the rifling.

I was also wondering if anyone was shooting the 130 or 140 grain Cutting Edge MTH out of a 260 AI or something similar. The 140 requires a tighter twist than most bullets in the 140 grain class (1:7.5) and I'm wondering if the 260 AI in a 24 inch barrel could push the 140 grain bullet fast enough to take advantage of the higher ballistic coefficient (.600 for the 140 and .550 for the 130) out to 1000 yards at the expense of higher pressure due to the tighter twist.