Did you really think about that, before you typed it? "Two-piece bolt" and "non-match chamber" are terms that apply to the great majority of the bolt action .22 LR rifles on the market - not just the 77/22.
Two-piece bolts and/or "non-match chambers" are found in most or all models from Marlin, Savage, Winchester, CZ, Remington, and Kimber. (And I'm sure I missed a few manufacturers.)
...Just the same old, unsupported, regurgitated, anti-Ruger internet crap.
I speak from long experience with rimfires and a great many accurizing projects, including several that have been posted on a well-known rimfire board for several years and recording more than 20,000 hits. My accurizing jobs have turned in remarkable accuracy, including my own 10-22 that shot an average of 10 consecutive 5-shot groups at 50 yards that averaged 0.37".
That said, I've also worked at trying to get the 77/22 to shoot "very" well and with factory barrels. It's been quite disappointing. Though made of high-quality materials, the two-piece bolt is not made to precision levels and doesn't fit in the action particularly tightly. I've heard of only one 77/22 that was extensively modified that shot reasonably well in rimfire benchrest competition, but didn't win any matches, as I remember.
Compare that to the Remington 540-series rifles that, modified, were used extensively as Sporter-category rifles that won many matches before advent of the custom rimfire action rifles that typically result in winners, but cost upwards of $3,000, some closer to $10,000.
That said, the 77/22 is a nice rifle. If a person wants a reliable rifle that shoots 1"-1 1/2" groups with non-match ammo at 50 yards...go for it! I just expect more out of my bolt-action rifles, especially those that cost what the Ruger does. I also expect that if I do some basic accurizing work on one, that it should group under 3/4" at 50 yards with non-match ammo, but ammo selected, by trial of various brands/types.