Mike:
I started here at SH, doing articles on marksmanship basics from what I had then perceived as a Tactical angle (Black Thoughts series) back in 2001; concentrating primarily on simple tricks and tweaks to the basic factory rifle. My view was that the factory has an obligation to its customers to work out the known bugs and to deliver a functional product. That view has never changed, and is a keystone in the foundation of what I post here.
As above, we all have that urge to mess with success, which is what most of the factory rifles are, especially in the past decade; to leave our mark on a personal belonging. For those manufacturers who are willing to compete on the basic performance level, this has led to success, and has given the customer a rifle that in the vast majority of hands is capable of delivering the shooter's potential, and usually a bit more, too. I do not begrudge the folks who devise and sell their most excellent upgrades, they work and have a place for many shooters. But not all.
I modify my rifles, upgrading things like stocks (often a first item to be replaced, given my nearly 6 1/2ft height), mounts and optics (if part of a package gun), and little more. Given my own marksmanship excellence (laugh here, that's a joke), more upgrading needs to be justified. In my own case, I get what I consider to be adequate accuracy for my own needs (1/2MOA to 1MOA) at this point, and further bells and whistles hold no attraction for me. But when I do buy upgrades, I also make a serious effort to find my improvments from among the more humble offerings. Honestly, the best is way more than I either rate or can afford. I know that given a stroke of brilliance (rare these days), my rifles can shoot better, confirming my own status as the crucial limiting factor. A lot of folks decide that more is needed, buy the additional tweaks, and are very often rewarded with improvement, but not all, and not all the time. That's because sometimes the component that needs upgrading can't be bought, but can be seen in the mirror each morning.
I've said it before, when my rifle does not deliver for me, close to 30 years of experience has taught me that the great majority of times the flaw is a human error, mine and nobody else's. That includes a failure to go over the rifle seeking loose stuff, etc. After that, nine times out of ten, it's trigger manipulation and/or rifle support. I no longer shoot enough that I'm courting barrel burnout, but it remains a possibility to check when doing rifle checkups.
There is no mechanical upgrade that can fill a gap in marksmanship skill. Add to this, "If it ain't broke, don't fix it...".
As a beginner, I will suggest that a good barrel and good ammunition, along with the marksmanship basics, will form the foundation of your progress and success. I am not suggesting that a factory barrel can't do this; as a beginner, a factory barrel can take the wear and tear that the development of solid skills requires, and will probably reach a point where increasing bore wear and improving skills intersect, perhaps justifying a rebarreling with a better quality replacement barrel. I will also suggest that in nearly all cases, handloaded ammunition can be load developed to attain accuracy potential that can be otherwise elusive when using only factory ammunition.
This is an old view, and is becoming less and less true as ammunition makers refine their act. But I'm still handloading nearly all of what I shoot.
Believe me, I would dearly enjoy finding factory ammunition that delivers my rifle's potential, and economically. I test new stuff, as I am preparing to do with Hornady's new Frontier 5.56 75gr HPBT Match offering. Simple test, does its accuracy equal or beat my own handloads? If not, but it's still good for 1MOA, then I'll likely buy it instead of making my own. I'm not seeking ultimate accuracy at any cost like BR shooters do so admirably. I'm looking to do these things economically, and at my age, time is at least as valuable as cost savings.
Understand that there are no shortcuts, and that the marksmanship basics need to remain always a part of each shot. Marksmanship excellence is not that hard to attain with good learning, but we must commit to the fact that on any given day, letting down one's commitment to the basics all the time is never going to deliver an improvement. In my view, it makes for wasted ammunition, and wipes out the efforts I have made to ensure that my ammunition isn't the part of a problem.
Greg