.5 MOA to me at 100 means zippo if I can't control the ES to mid teens or lower. I would rather have a gun shoot .7 MOA with a ten shot ES of 10 than a .4 MOA gun with an ES of 60. For long flight times controlling muzzle velocities is just as if not more critical than group size at short range. Obviously your goal is to have both of the best.
Keep in mind the differences between grouping-vs-accuracy and target shooting on animals-vs-hunting.
1/2moa of grouping off a bench might not get it for hunting if your field accuracy with it isn't good enough. In other words, 1/2moa of grouping is not always +/- .25moa of accuracy.
For groundhogs I actually need 1/4moa of cold bore accuracy off a bipod. That is 1/4moa from my mark, or +/- .25moa of accuracy. With this, my max range is limited to that capability, and at the moment I have two 500yd guns for GHs. Took a lot of work to get that(more than just load development).
The problem im having is that in the past with factory rifles if I got .7 or .6 I was a happy camper now with a custom rifle.................anything over .4 im dissatified with.........................my .243 Ai has shot a lof of .3 .2 and some .1's but not consistantly, thats the problem....................consistent would be .5 or less.
Past a certain point, I view obsessing over group size as being counterproductive. I have never fired a ten or even a five shot group at a game animal. It's far more important to know where your first and second shots are going to go than it is to know your average group size at a given distance. The only useful thing group size tells you is what the maximum mechanical accuracy of your rifle/load combination is so that you can then determine when you are shooting it to its potential. The rest of the error belongs to the shooter.
I would bet that there are not more than a handful of people on this entire site who can shoot a 1/2 MOA rifle to its maximum potential from field positions under field conditions. The number of them who can tell the difference between a 1/2 MOA rifle and a 1/4 MOA rifle under field conditions is likely to be even smaller than that.
From what I have seen, the primary purpose of group size is to have something to brag to your buddies about when the stars align perfectly and you shoot the best group of your life from a bench on a square range. Of course there are plenty of keyboard commandos out there who shoot better groups than you do on your best day without even leaving the house.
The bottom line here is that most people's rifles are far more accurate than the person squeezing the trigger. Once you have wrung out your rifle/scope/load combination and know what it is capable of if you do everything possible to take the human element out of the system, it is time to work on accurizing YOURSELF. With very few exceptions, even with a basic factory rifle, the least accurate part of the system is the shooter and that is the part of the system that needs the most attention.