There is not a SAAMI spec for the 243AI cartridge. AI reamers are cut to the buyers spec, not a SAAMI spec.
With the info posted so far I do not see it as a problem other than a snug chamber if he wants to use factory 243 ammo in the rifle, even at that there is at least one brand that does chamber. Cooper has already offered to open up the chamber a bit more if he wants that done. With the group showing on the test target I would shoot it first before sending it back to have the chamber opened.
I have a Rem 700 in 243 that had the same issue with having to seat the bullets even deeper than what is shown in his picture in order to chamber the cartridge. As far as I was concerned it just gave me more ability to chase the lands as the erosion ate them away. The standard 243 eats away the lands very quickly and I imagine that the 243AI will do so even faster. If you have the opportunity to borescope a 243 with 1000 1200 rounds through it that will ruin your day.
drover
I believe the 243AI version helps reduce the erosion, despite burning a bit more powder.
