Re: Is it needed?
i have both, the stripped down walmart version of the mkii (f model) and the BV (bull barrel). i feel a "pencil" barrel vs. "marker" barrel comparison coming on....
i did notice though on my "f" model, the receiver has a gap in it and the barrel is pinned. i'm not a gunsmith, and perhaps someone can enlighten us on the procedure, but possibly getting a "f" model at a lower price and "upgrading" with a bull barrel later may only take nocking out the old pin, taking out the pencil, putting in the bull, and putting the pin back in. sounds too simple to be true.
i like shay's views on the thickness ratio and have thought about that before, but have no data to back it up other than the biggest advantage of the bull is to reduce harmonics and barrel "whip" and to reduce the "heat swelling / warp" of the barrel, if that's what you want to call it.
however, how much recoil and heat is produced in a .22 to cause those things? not much. you'ld probably be better served with a barrel tuner.
unless you are shooting benchrest where groups are seemingly measured by fractions of a hair, i don't think the bull is needed on a bolt .22, nor the flutes you see coming out.
now if your trying to do a trainer to match the weight of it's centerfire big brother, that's a different story.
i believe if you call savage, they may be able to send you a bull barrel to replace the regular. i don't know how much it would be, but worth a call.