From what I've gathered listening to what I could find coming from actual engineers that some of the ammo makers have on staff these days, dudes that have studied this stuff deeper than any of us likely could:
Statistically speaking... a guy using good rifle components (stock/chassis/action/barrel/trigger) and using good reloading components, and who also happens to be a really good reloader (as in better than the average guy who owns a bunch of reloading shit)... can expect being able to put together a 1/2 MOA gun that stays that way over the life of a barrel (again, if they're really good).
Some are going to be luckier than others more or less based on how much better of an "ammo factory" they can run. Obviously, the more consistent the ammo is, the more consistent the gun.
How good your "ammo factory" is, is what's most directly responsible for determining the Standard Deviation numbers you will see when you shoot over a chronograph. It's not a magic powder charge or magic seating depth number, it's how good you are at making the exact same round over and over again, so they're all as exact as you can get to them being "clones" of one and another.
Obviously, some are going to see better than 1/2 MOA (especially at 100 yards), and that can also be dependent on how lucky they are, but it usually also has a lot to do with how they choose to load.
Option #1:
If all you care about is small groups, or trying to get the smallest groups possible at a set range: then load close to the lands and/or jam the fuckers. Because it works, every time.
However, don't be surprised if your waterline/POI at different distances is garbage, and trying to get your MV and BC to line up and play nice with what your ballistic calculator spits out may be a shit show as that's a known resulting trade-off. It will also probably only get worse as the barrel gets hot.
For best results, go total OCD, shit like: when you seat bullets, you might want to first seat them a little long, then on a second pass, seat them again OCD-style using calipers and a comparator measuring CBTO so they're all within a thou or dead nuts.
Option #2:
If you want a gun that's boringly reliable at multiple distances, you really can't get caught up chasing bug holes at 100, you'll need to find a bullet-jump that is as far off the lands as you can go while still being able to print a .5" group at 100 on command (and/or a 2" group at 400 on command, etc, out to 1000 or so).
For some bullets, that very well might put one as close as 0.020" off, but most of the time it's no closer than like ~0.040" off even with the most finicky VLD's out there. These days in PRS-style circles I hear ~0.070"- 0.120" off as more the norm than the exception it once was.
Why jump? The lands erode less quickly so the barrel stays "the same" longer, it becomes more forgiving to the variances in seating depth of a few thou that most of our seating dies produce (even the best ones), and the waterline/POI/vertical dispersion becomes predictable and consistent downrange (all the way downrange).
Using a healthy jump, one can true their MV at 500-600, true their BC at 750-1000, and pretty much not have to worry about their dope again (other than weather and wind). On repeat range trips, most times all that will be needed is to update the weather in your solver and go shoot, getting first round impacts at distance.
For me, I'm not a guy who spends too much time specifically shooting groups, but I do practice them enough to know the difference between me sucking at shooting vs the gun sucking at shooting. I believe it's important to be honest with yourself about that fact to get anywhere (a LOT of guys aren't). I just look for multiple holes touching at 100, usually 3 out of 5 or so, or 2 out of 3, enough to know it's not just a coincidence. Once I see that I'm getting that over and over again, without trying too hard, and they're all .5" or under at 100 (1/2 MOA)... my load development is done. With a new barrel I put 200rds downrange at .100" off using a safe middle-of-the-road charge based off whatever the book charge is before I make any decisions and set anything in stone.
Once I have a set load recipe, it is what it is until the barrel dies, it never changes.
