a few years ago, bought a slightly used Browning X bolt, 223, wood stock, nice rifle. Put on a scope, and it would not group at all at 100 yards. I was frustrated, and checked the on-line spec's of my Browning, suggesting it had a quick twist. Then I checked the actual twist with a cleaning rod, and found my rifle was a 1/12 twist, and not accurate with my heavier 62 or heavier rounds. So loaded up some 40 grain Vmax, and my rifle immediately shot one inch groups at 100 yards.
I dropped by the selling LGS, and mentioned that all it needed was the correct wt bullet, and the sales chap, a friend, told me the prior owner brought it back because it wouldn't shoot. I suspect he was shooting store bought heavier bullets, and all it needs is the 40 grain bullets to match its 1/12 twist.
So a suggestion when searching for a bolt 223, check the twist compatibility for what you have to load it with to. NV