That's why I say a AR platform would be a good one to experiment with. Use the same gun with a different barrel,and you can reduce some of the variables that way and you'll get a more accurate comparison on the actual barrel differences.
It seems that 3/4 or less is about the norm for both my AR platforms with "good ammo" like Lake City, that have non chrome lined barrels and other than chucks @ extreme ranges I generally don't miss either.
Back in the day when I was competing , if I didn't end up with 1 ragged hole, it was time for more work. But sense I don't compete anymore that 3/4 groups work just fine for general hunting and plinking,,plus the old eyes just aren't what they used to be,,so they just may shoot better in different hands, but that's as well as I can shoot now days. But for my purposes, that works just fine.
the best way to get a answer is look at what true competitors do .
bench rest guys spend thousands on barrels every year an if there was a way to improve life an retain accuracy they would . I dont see any bench rest rifles with chrome bores .
to do a comparison you would need have identical profiles. chambers, ammo etc . Im told a properly chrome lined barrle has to be rifled differently so that will factor in. super accurate rifles generally have a short break in periond were things smooth out an after they shoot better . with a chrome lined barrel your going to be stuck with what you got.
I have seen some pretty accurate ATs with chromw barrels . I have seen 1/2" groups but in a the target shooting world that is not very accurate .
Im sure there are kept records in classes were AR,s compete as to what the best is . I just doubt yout going to see a chrome lined barrel win in a class were the gun in the major factor in winning .
I know the browning an winchester WSSM rilfes all have chrome lined barrels .
Trust me If I could have a 22-250 barel chrome lined an keep the throat living longer an keep accuracy for a $100 or so more Id do it in a heart beat .
I have to rebarrel my 22-250 bolt action target gun an Im looking at $400 for a new barrel . :(
i have seen a few chrome lined barrels do 3/8ths of an inch @ 100M.
i do think this is exceptional and not the rule.
i have seen a few stainless steel "uber $$$" barrels that could do UNDER 1/4th by quite a bit.
my thinking is if your running factory loaded ammo --a good chrome lined barrel is going to shoot better than the ammo will allow.
we need to take a uber match $$$ barrel and load it up on factory ammo and see what it will do --LOL!
That's a good point j427x, I've shot surplus SA5.56 out of a 1-8ss bull barrel and got around 3"-4". That same barrel is sub M.O.A. with hand loads.
Well, not to brag or anything, but I can group so small at 100yards that Bill Clinton and Obama could DP it and not tear the paper......
you should see what i can do with a bolt action firing those plastic indoor training rounds @ 100M!--LOL!