I just went through the biggest mind screw of all when it comes to accuracy in a rifle. To make a long story short. My favorite hunting rifle in a standard contour barrel seemed to have lost it's edge and started stringing shots like crazy. After a few hundred rounds and a lot of tinkering it's back to shooting solid groups again. But here's the key I'm back to the original accurate load it liked to begin with. It was a stock issue and how in the world it had changed or moved is beyond me. So the end result is I got my confidence back in it and it's shooting just like it was brand new.
The thing is most of us are buying factory hunting style guns $1000.00 or less. I'm sorry to say but unless you get a really really good one off the shelf your going to spend a lot of time on the reloading bench tuning a load to the rifle to even remotely compare to a rebuilt rifle or custom gun that someone has chunked a ton of money into.
I know everyone says my gun puts holes in holes at 100yards. I consider myself a pretty decent shot and it takes a really well put together rifle to be able to do that consistently. I'm not happy until mine are at least clover leaf'in at that range. Human error is a common factor in all this. Among playing with rifle mentioned above I tweaked my shooting form that had been slacking. There are so many variables to making a rifle shoot in that sweet spot. Best thing is to start reading column after column of articles and try them all sooner or later you'll find your issue and possibly an easy fix without dumping a ton of money in a $500.00 gun that's tolerances are made to accommodate every round on the shelf at the gun shop.
100yards is not the best place to test accuracy of loads in a rifle. Spread that range out to 200, 300 and 400 yards and start testing loads and shooting groups. You'll find what your rifle likes. It may not be all that spectacular on paper but remember if your staying under 1" at 100 yards then you should be able to stay under 3" at 300 yards and so on. So you shoot 500 yards and got a 4 1/2" group your right where your standard factory rifle's tolerances are probably made for. But running MOA or better at the appropriate range is no room for complaint for a standard factory rifle. That's all they are made to do.
But every once in awhile you'll get a really nice shooting factory rifle. And when it seems to go out of whack go back to the basic's before going to the gunsmith. I think your rifles will find what they want to shoot and if they don't go see the smithy but your going to start to spend some cash.
For example my 300 win mag has .313 of jump before the bullet touches the lands it shoots this way the best always has. That's the amount of tolerance that a factory rifle will have. Most really accurate rifle like to be right at the cut of the nut into the lands for the best groups. I have a ton to learn and chasing bullets around in the chamber is a lot of time at the range. But that's it the more time at the range the better you get and that in itself takes out another variable in the equation.
So maybe your just like me and can shoot have confidence in your shooting but we have a lifetime of knowledge to learn on exactly how to make just more than one rifle shoot and shoot well 100% of the time. Even the best benchrest shooters will laugh at the 100% of the time comment. They know better. I'll settle for a good day and a good group or two at the range at distance to know I can count on one particular rifle.