I believe the only concern would be the weight of the rifle,is it a big heavy benchrest shooter?You wouldnt want to pack around a heavy rifle while hunting all day.I wouldnt recommend the cartridge for anything larger than deer,you could get the same shooting performance out of a 7mag or 300win mag that are bolth great all around hunting cartridges.

In a hunting rifle, accuracy should mean groups of 1-1/2 inches or smaller. All commercial hunting rifles sold today are sold with the standard that they will produce groups of 1-1/2 inches at 100 yards. Generally speaking, such a rifle could be considered a 400 yard hunting rifle. Of course, every one that I have seriously tested has shot groups of around 1 inch at 100 yards, with the occasional group that's a bit smaller.

Custom gunmaker Kenny Jarrett builds rifles for both commercial and wildcat cartridges that shoot groups of 1/2 inch at 100 yards and sometimes even smaller. Of course, you can't even read through a hunting or shooting magazine anymore without noticing how every new hotshot round gives you sub-minute of angle groups every time. I have yet to see where any of these are more accurate than what is already out there. In a hunting rifle, there is only a certain amount of accuracy that you can take advantage of anyway. If your gun shoots groups between 1 inch and 1-1/2 inches at 100 yards, be very happy with it.

Some rifles are picky. A lot of times, a particular rifle does especially well with a certain bullet design and load. Reloading gives you the option of working up special loads or pet loads, for your rifle. It also gives you the option of using powders that give you better ballistic performance than could be obtained from factory loads. As an example, generally speaking the factory-loaded 270 Winchester comes closer to handload potential than does a 30-06.

Sighting in properly also comes into play. I once saw someone sight a 300 Weatherby Magnum over 4 inches high at 100 yards. Given the velocity, and the fact that I could find no figures for this anywhere, I can't imagine where the heck that bullet would have been on target at. I believe the figures said about 2 inches, or a little more, and you have a 300 yard zero! For a very fast round like the 270 Weatherby Magnum, all you need is about 1.5 inches high at 100 yards. For a slower round like a 270 Winchester, 30-06, and similar rounds, I like about 2.5 inches, roughly. I like that approximately 200 yard zero. It keeps the bullet close to the sight-line.

For hunting and plinking, you probably don't need a .300 or .338 magnum. If you are going to hunt deer, a 243, 25-06, 260 Remington, 7mm-08, or 270 Winchester should be perfect. If you are planning to hunt elk, I don't see why a 270 Winchester or 280 Remington wouldn't work nicely. A 308 Winchester is also a fine choice. You'll probably want a rifle with a 24-inch barrel for these calibers if there is a possibility of long-range shooting.

Agree with MTWACKO. Especially if you ever think you might take this rifle elk or sheep hunting. After carrying a rifle up and down mountainous terrain all day, you're going to want it to be LIGHT!

Pretty much anything you get from the major manufacturers is going to be accurate enough for hunting. Shooting when hunting, though, is very different from shooting in a competition. You may be tired from humping up and down a mountain. You will probably be pumped up some with "buck fever," even after you've been hunting for many years. You probably won't have a bench to rest your elbows on, let alone sand bags to set the rifle in.

What all this means is that the fact that you can keep your shots in a 2" circle at 400 yards from the bench doesn't mean you can responsibly take 400 yard shots when hunting. Try running in place for 2 minutes, to get yourself a little sweaty and winded, then within 10 seconds stop, drop into a sitting position, and snap off a shot. How close was it to your expected point of impact? That is, for example, if you're sighted 2" high at 100 yards how close did the bullet impact to precisely 2" straight above the bullseye?

This will give you an idea (though only a very rough idea) of what kind of field accuracy you'll get when hunting. If that quick shot after working up a sweat is 3" away from where you expected, you should limit your shots to not very much more than 100 yards.

The truth is, most hunters should probably limit their shots to not much more than 150 yards or so. I'd guess that less than 1 in 50 has any business taking a shot past 200 yards. Most of those who participate here are probably good for somewhat greater distances. I say that because, the fact that you're here talking about and thinking about hunting and shooting at this time of year is a pretty good indication that you take your hunting and shooting more seriously than the average, "fire two shots to sight it in a week before the season" type of hunter.

Still, I'd also guess that the majority of shooters (including those here) are over-confident in their shooting abilities and as a result over-estimate the range at which they can take a responsible shot. The good news, however, is that most hunters also tend to over-estimate the range to the animal they're looking at, so it probably balances out in the end.

Good luck!

When I shot a big buck in Arkansas during the Christmas hunt of 2004, I honestly hadn't thought about the distance. When I made the shot, I guess I thought it was a fairly long shot, but it didn't actually occur to me until I was walking out to my deer and realized it's taking me a very long time to get out to this thing. I later found out from my friends, who were set up nearby when they ranged from my spot to the deer that it was almost 300 yards. I had never even considered that until they brought it up, I just remember stopping and thinking that it was taking me a very long time to walk out there.

I think your choice of an M21 would be fine. Sure the bolt action crowd will give you some strange looks, but who cares? If you've been shooting high power with an m14 or m1, this would be a natural extension. Why not just take what you've been shooting at your competitions?

I would also consider either the "standard", "loaded standard", or "national match" fine for hunting, and less costly if you should bang it up, which can and will happen. Of course you could take the action, trigger, and barrel group of the m21 and put a beater stock on it....

Just something to consider; hunting isn't long range paper shooting, for the simple reason that the targets move. If you have been shooting high power, I have little doubt you are a great shot. However, don't take head shots, simply because while you very well may be able to make the shot perfectly, animals move unpredictably. They sneeze, they twitch, they jerk, they are just unpredicatable. A small shift could make the difference between a head shot killing and wounding. The same shift on a chest shot; however usually still keeps it fatal. Just some helpful advice....

Welcome.
For longer shots I prefer a rifle that has some weight to it.
Of the three rifles I take out on hunts. Where I know the shots will exceed 200 yds, I prefer the heavy 26" barreled (was 30"), 9-1/2 lb 270 wsm. I can have enough time to set myself and hold this rifle very steady in a standing position. I can also set it up so the maximum PBR 3" high and 3" low is 0-305 yds.
The other two are light barreled 7-1/2 lb rifles that shoot very well. They do well when quicker shots are the rule but, I need to find a way to steady myself on longer shots.
Hunt with a rifle that you feel comfortable with. If you handle a heavier rifle well. I say. Use it. The 308 win is a sweet round and it get real sweet when hand loaded with 150 or 165 bonded core or partition bullets.
Some research on anatomy would be helpful for bullet placement. With your experience. Placing a round between two ribs behind the front leg would be a cinch, at any capable range.

Are you serious about placing your shot between 2 ribs?Can anyone confidently say they can do that on a regular basis and depend on doing it to make a goog killing shot?3/4 of an inch in either direction and you hit a rib,mild breeze,gust of wind,animal turns 1 step or you miss,not a cinch for any shooter.You would have to have xray vision to know where the ribs are on every animal in the field.

The kill zone on most light and medium big game is about 8 inches in diameter. So if you're deer hunting, the maximum range at which you can put three to five shots into that circle should be your maximum allowable shooting distance. With elk, it's a bit bigger, but I'd still suggest using the 8 inch standard. I normally aim just behind the front shoulder.

No.
It was a round about way of seconding Bitmashers suggestion about not taking head shots, just because you can.