Alan, from what you have shown us over the years, it would appear to me when you need something that is important to what you are doing, you get it.
In this situation, you need a rifle thats easily accessible in a hurry, say out of the case in the pick up truck or what have you, that you shoot well, fits you well and is set up for the range you need to hit the target at, and we all know you live in some open terrain, flat and so on.
I'm not sure what caliber that 721 is, and what kind of groups you can get from it say off a bench rest, with what ammunition, but if you can sort that out and can mount a decent scope on it and duplicate those groups at range, from a bench, then its more on you than the rifle. If this particular rifle just does not perform off the bench, you may have to consider something that will provide results, I'll use a savage tactical in a .308 for example,(I forget the model) that rifle and even though a shorter barrel is just a tack driver and performs like that once dialed in, easily, and I'd like to say every darned fool who picks one of these up can hit some tight groups, I was impressed by this rifle, given the cost to buy it and put optics on it, a friend has one, heavy barrel and impressive rifling, and he did not have to sell the farm to get it, anything along those lines would perform well for you. shorter barrel might even be better in the tractor or pick-up. You want that performance, simply put, in whatever you shoot, regardless of the model or caliber, and given the modern times we live in, something is out there that will fit you but good.
Optics, where you are I'd not go cheap, likely fixed is better for you, but just look at the specifications and compare. Ideally a range finding scope with graduated reticles will help immensely at known ranges, once you are sighted. Red dot or illuminated reticle, and something that is good in low light, meaning the last number of the scope dimension is larger, say like a 56mm wide angle like my springfield M1a should have on it. If this s.o.b. is eyeballing your herd, its fair to say you might be after him/it at dusk or dawn and I will say this, that there is no subsitute for optics, something that lets more light in, and has low parallax might be a good place to start when fitting a rifle, not sure about the height your 721 will allow, or what hardware is available to put good optics on it if in fact the rifle can be dialed in.
Personally, I just have to say I think the M1A I have is a great rifle, its heavy and was meant for an infantryman or rifleman, as a battle rifle, and its a lot heavier than most bolt action rifles.
.308 is just a versatile round, for reloading if you like, or regular ball ammo, or what I use off the shelf, federal powr shok, 150 grain, soft points. This rifle I can shoot well from any position, and thought its heavy, I have numerous times come upon my prey very quickly and raised up and hit what I shot at, deer, woodchuck, even muskrat, there are times when you just have to raise up and get it done, and this rifle does it every time. I like the person mentioned below, will use it for smaller vermin or large game, as long as the back stop is safe or no worry, most of the terrain here provides that safety.
The other thing is, not being a practiced sharpshooter by trade or a living, you can get rusty or what have you, but I can pick that thing up and use it effectively in a hurry, I saw a coyote park his @ss on my hill one afternoon, got into a sitting prone position and that was that.
The one thing I like about the action is the reliability, no civilian semi auto performs like military actions, or at least ones I have tried under the same conditions. I regularly shoot whitetail deer at 250-300 yards, and closer, a year ago I missed a buck by a hair on the first shot, and he was in a tough place to get a shot, but being a semi, the short window I had, I reset myself very quickly, and hit the vitals, a buddy of mine was in his stand and heard it and noticed how little time in between there was, had I needed to chamber another round, it would have been gone. I carry this rifle with full confidence in what I need to do, and regardless of what you have that is the priority, because its hard enough at longer ranges, ones shooting etiquette, excitement and figuring wind, elevations per the range and what you are doing factor in as well as other things. Its almost fair to say you need to develop a relationship with what you shoot to have that confidence. The optic on mine is an insult to the rifle, was like an $80 Simmons 3x12x44mm objective, yet its done the job, and the mount on these things, installed correctly, knocking around the cab or what have you will not throw it off, and I can use the peep sight under the scope if need be.
Many prefer the caliber for the prey, and other reasons, but when you just can't afford to have all these great rifles in calibers you want, its nice to have that reliable tight group shooting workhorse like one of these. My preference, everyone is wired different, and seems most on here give good advice, and the bottom line is I hope you get that sorted quickly, I can't imagine dealing with losses out of a herd that you nurture with all the hard work, especially during winter, best of luck in getting it done and please post back how it works out and how it got done, be interested to hear !
