Not sure if you're hunting or plinking, but I've got about 1k rounds down my 6.5 creed all at the range. It's a savage 10, 1-in-8" twist 20" barrel. My experiences with factory are as follows (5-shot groups @100y, price @ cabelas or my local shop, general thoughts.) I'm a good enough shot that I think I hit the ceiling on most of these rounds and my given sizes are fair (my handloads are .2-.4" and I don't neck turn or wash brass. I can shoot.) These are my experiences with my barrel, and savages are weird, but I think what I learned reloading these cases backs up the generalizations.
Winchester gray box, 125g: (was an open tip hunting/match mongrel, now a FMJ) .9-1.75". $15-18. Good trigger practice and warmup. Not the worst, cheap. Appears to have been relabeled with a different 125 grain bullet so current accuracy likely different.
Winchester red box 125g: same as above. $21. huge jump in price since I bought it. Not worth it at that price, but still a cheapish warmup, or fouler after a deep clean.
Winchester Black box 140g: .8-1.2". $28. Absurd price jump in last 10 months. Okay round, bad price. Uses name brand target bullets in cheap brass with inconsistent burn. best of Winchester but only buy if Hornady and Sig aren't available.
S and B black box 140g soft point flat base: $16-20 I think. 1.25" Identical performance to Core Lokt, maybe fewer wild fliers.
S and B tan box 140g FMJ: $14. Slightly better than the black box above. Best of the cheaper, less accurate stuff. Also, the very cheapest. Sold gleefully in my local store as SHTF ammo, like I'll be sniping the jackboots off the gendarmes, especially with this stuff. For the record, the bullets look like crayons. Exactly what I'd expect from the French, and I'm French.
Federal gold medal 130 grain Berger OTM: 32-35 bucks depending on the store. 1.25-1.5". Garbage. Absolutely the worst I shot in any gun ever. Supposedly the dog's bollocks in other guns but the cases were too long for my chamber. Much longer than they should have been. Past trim length before firing AND a crush fit on the shoulder. An inaccurate waste of money.
Nosler Ballistic Tip 140g: $34. 1.5". Biggest surprise of them all. Not awesome and not a deal. For me. I suspect that it was just in the worst possible velocity node for my gun. Nothing discernible I could find wrong and well worth a try in another rifle. The only round I tried I would hunt with. I should try it again after bedding and new rings actually.
Hornady ELD Match: 28 on sale, 32 or so off sale. 3 different weights: 120 grain: fine, my gun didn't love it. 1.25". 140g: Pretty good on sale, 3rd most accurate, .8-1.25". 147g. .6-1.25". Second best most accurate overall for either value or accuracy. Sorta worth the full price but don't trade anything nice for it. Reloading the cases I learned that basically Hornady puts really nice, high value bullets with good powder and good measurement into cheap brass. Which is frustrating because if it weren't for GIANT flash hole burrs, case neck and volume variations nobody would ever sell another creedmoor reloading die or loaded round.
Remington Core-Lokt 140g Soft point flat base: $22. 1-1.5". This stuff is fine. It tends to put 3 in the same hole then 2 more someplace else entirely. Some guns might like it and shrink that up by a quarter inch. Close to being a great value. Technically a hunting round. It's accurate enough for killing but I do not trust remington bullets above 2500 fps after seeing some deer shot and doing my own testing.
THE BEST: Sig Elite performance match. $26, often on sale for 22 or so. .5-.9" For me if I wasn't reloading I'd buy all I could afford when on sale. Sierra match king bullets, consistent powder charge, great primers, and only minor brass deviations. Oddly, it reloads poorly becaus ei think the brass is overly hard but it is very consistent stuff. I've shot maybe 200 rounds of it, I've seen others shoot it. I've split a box with another guy. Same results every time in every gun I've seen. The best deal going at any price.
It's long but I hope this helps.