1:7” and 1:8” twists are more utilitarian, as they can run a wide range of ammo. The slower twists can be more beneficial to the 55gr for accuracy, but you shouldn’t really be buying a barrel to specifically use with 55gr bulk ammo for the purpose of precision shooting because the 55gr FMJ (and 62gr FMJ for that matter) are not match loads and buying them for accuracy makes little sense other than simply having nothing else available at the time, which is a supply issue. If you legitimately want longer range accuracy or capability, set the gun up to run a proper match load like a 68-77gr match bullet. The 1:7 or 8 twist barrel will get the 55gr bullets out to 500yds, and I’ve done it numerous times. Just don’t expect miracles because the bullets aren’t going to perform any regardless of barrel twist.