It'd help to know "which" Puma you have - as said above, there've been different importers and makers. Of the early ones, Rossis, the first era mentioned is Interarms (mostly 1980s-90s) then the "Puma" name and gun was taken over by Legacy (LSI) as the largest Rossi importer. Around 2000, Rossi retooled, improving upon the issues noted - primarily somewhat stiff (but still strong and smooth-able) actions out of the box. Around 2008 is when LSI switched manufacturers to the pricier--and nicer cosmetically--Italian-made Chiappa (Armi Sport)--nd taking the "Puma" name with them. Since 2008, the sole importer of Rossis is Rossi itself, under it's relatively new Braztech/Taurus ownership...though it looks like EMF may have gotten back into the Rossi business after a few skimpy years. If so, I don't know if they're just direct transfer over from Rossi-Braztech importation or finished to their spec like their earlier (late 90s-2008 or so) were.
I've had eight or so Interarms and EMF (another importer) Rossis of various calibers. They've all been ultra reliable and smooth shooters, and a lot of the aforementioned stiffness found in some guns can be smoothed through dry levering or shooting. I shoot RNFP 200-240 gr particularly well. One of my current .44 Mags shoots .44 Sp very reliably, one "pretty" reliably and one doesn't like them at all. I'm told it's fixable--possibly. In both .357 and .44 Mag, they can be finicky about their shorter "Special" counterpart cartridges. Different guns, different personalities it seems. Steve Young (aka Nate Kiowa Jones) of www.stevesgunz.com
is one of the top 92/Rossi specialists who can advise further (and has a d-i-y DVD in addition to doing slick-ups himself for.a lot of satisfied customers).
As to bore, some
Rossis were over-bored in the .44 Mag guns for awhile--supposedly a glitch due to over-catering to some Euro-market specs. I do not know the specific timespan other than some of the early 2000s period, IIRC. Again, Steve Young is a good one to ask about this if someone else doesn't chime in.