I've only used 'em (the Barnes XBTs) in "marginal calibers/velocities" - due to the perceived (& later experienced) added penetration required - in our "short-barreled" Rem M7s & a Contender pistol round. (BTW, I've yet to play with any of the Barnes' flat based bullets)
They've worked plenty "good enough" for hunting accuracy = just at "100 yard MOA," - (yeah, I know ... )
All my twist rates were at 1:10" - velocities were at 22-2600 fps - & calibers of 7mm through .308" - 140s through 165s repectively.
Barnes bullets seem to "work" for some & not for others re accuracy. Still, they have, in my experience, very "acceptable enough" hunting accuracy. In every one of my hunting platforms, the Barnes have shot sub-or right at just +MOA groups - worst case.
From what I've noticed (throuh a
very personal & limited experience, Barnes coppers XBTs won't give
The Best accuracy, but will do good enough at-or-sub 1.5 MOA - worst case & that with not a real attempt at wringing out the very best of the best - likely, playing with some other powders, etc. could do some better.
Thing is - I do a lot of less-than 30-yard (I call it "bow-hunting with a rifle") dark-timber elk-hunting. Deer, obviously fall into this same category. MOA doesn't really come into play, but I still do the 300-yard+ "plaything" with these same loads - I do want to know what they'll do at 300+ yds in case I'd want to shoot somethig towards 300 yards & the Barnes'll do, in my stuuf & without a complete wringing out of the whole handloading bit, an easy 1-1/2 MOA grouping.
For everything, these Barnes shoot through everything to date & at every range I've used 'em.
I do hate their cost, but for a "marginal caliber bullet," I haven't seen anything that'll do the job better. 'Course too, I haven't used any "lesser bullet" to prove my point neither in these "sub calibers."
(BTW, in these "sub-calibers," I've harvested CO elk 4-for-4 to date - that "bow-hunting with a rifle thing" tends to get whatever it is you want ... it's a hunting kill-set ... really, if you can kill it with a bow 'n arrow, you can certaintly do the same with any rifle/suitable handgun)
I've done quite a bit better for accuracy, but haven't yet had any bullet penetrate (& kill) anything better yet.