10/22 Accuracy Theory
Your rifle is a machine, just like your car or your refrigerator or a doorknob. It is a combination of moving and static parts designed to send a tiny projectile down range at tremendous speeds. So how do we make it do that better?
There are three primary aspects of accuracy: accuracy of the rifle, ergonomics, and the trigger control nut.
First is accuracy of the rifle. This would be best described by clamping a barreled action in a vise, with no stock, hammer, or other bits attached. Chamber a round, hit the firing pin, and see what the bullet does. With nothing moving or interfering with the bullet, you have the maximum possible accuracy for your rifle.
Holding the barrel in one hand and hitting the primer with a rock isn't not exactly practical, so that brings up everything I call 'ergonomics', or everything which allows us to actually shoot and handle the rifle. The action, stock, trigger... these are all elements of ergonomics. The goal with these is to make them as comfortable and solid as possible, while minimizing their impact on the rifles' actual accuracy.
Last, and often the most important part, is the trigger control nut. (That's you, in case you didn't know) Of course you want to start with the most accurate rifle possible; you don't want something which will amplify your shooting faults. But here's the issue, spending $1000 on a 10/22 will not make the rifle hit the target by itself. There is a happy medium here. You might get much better results by spending $500 on your rifle, and the other $500 on shooting lessons.
You can see why it's important to determine WHY you aren't grouping shots like you want. If you clamp the rifle in a rest and it shoots terribly, consider a new barrel. If it shoots fine then the problem is you, and you will need to determine how to fix that. Do you need to buy classes, or just more ammo to practise? Or do you need to get a trigger job and a better stock, which will allow you to hold and fire the rifle more like the rest does?
The barrel is the heart of any gun. It is what holds and controls the bullet from the time it is chambered until it leaves the gun. You will have the greatest accuracy by getting the most precise barrel you can afford, and then making sure everything else lets the barrel do it's thing unimpeded. In other words, your first purchase should be a barrel, and buy a good one even if you have to save for it.
This is the core principle of accuracy; making sure that nothing on the rifle interferes with what the barrel is doing!
The subject of 'barrel harmonics' is huge and hotly debated, but for the moment lets just say that the barrel vibrates and has various 'waves' of motion as the bullet travels it's length. And lets say that the magnitude of this motion is directly related to the size of the bullet versus the size of the barrel. A .308 bullet traveling down a light-weight sporting barrel is going to cause vastly more movement than a .22LR bullet traveling down a solid 1" bull barrel. Makes sense right?
On most rifles you want to make sure that the barrel is 'free floating' because of this, allowing the barrel to vibrate and move evenly and unimpaired, improving the chances that every shot will be exactly the same.
Furthermore, the stock and barrel are going to move independently of each other throughout the day. Humidity will cause the stock to swell or shrink, putting more or less pressure on the barrel, causing your point of aim to move. And as you fire multiple shots, your barrel is going to heat up and expand with the same results. This is why on some guns the bullets will tend to 'string vertically' as the rifle warms up.
The issue with the 10/22 barrel is the way it fits in the receiver. The receiver is lightweight machined aluminium, and the barrel is simply clamped in. On a standard rifle the receiver is solid steel, and the barrel is threaded into it. This allows you to fairly easily bed the receiver and float the barrel.
But using the standard hardware, you cannot expect to properly float an 18" bull barrel that's just clamped into a lightweight aluminum box. It's going to move and flex a lot in relation to the receiver, hurting accuracy rather than helping. Even more important perhaps, the barrel is only clamped on the bottom, literally pulling the barrel down.
There are two options. First, through a good bedding job you can float the barrel, and then there are any number of gadgets and methods out there to pry the barrel up and hold it up there. This is important both so that your barrel is more aligned with your optics (which are clamped to the receiver not the barrel) and so that the bolt is more squared up with the barrel when the action is closed. This method is probably going to give you the best accuracy if you get everything dialed in correctly. That process is varied, hotly argued, and far beyond the scope of this article!
The second (and more old-school) option is to bed the barrel and float the receive. Going back to the amount of vibration this tiny bullet is producing in a heavy barrel, it makes sense to fully secure the barrel in the stock. The receiver is the lesser weight, so floating it makes for a minimum of weight or other pressure tweaking the joint with the barrel. This will be especially effective if the optics are mounted on the barrel. Volquartsen sells a barrel with a machined Weaver rail that runs back over the receiver, without touching it. This is the method I use most commonly, and generally run on my own guns. However I do not shoot bench rest and if I did, I'd doubtless use the first option to really dial everything in.
The stock, as has been mentioned, does not actually improve accuracy, although it is the most common after market part sold for the 10/22. The only way it can effect accuracy is if it is somehow flexing the barrel, or the barrel/receiver joint. That said, I know that I can shoot a heavy thumb hole rifle much more accurately than the factory stock. A good stock should weld itself to you at all the important contact point, and to this end, it's important to purchase a stock which fits the WAY you are shooting. A lightweight tacticool stock with an adjustable butt would be good for quick point ability and lightweight for packing around in the woods all day. A heavier thumbhole stock with a flat forend is much better for bench shooting.
Another example is with length of pull. If you are shooting prone off a bipod, a longer length of pull will fit nicely. If you are shooting off hand, a shorter one will feel more solid and less front-heavy. If you will be shooting exclusively one way, buy accordingly. If you think you might mix it up, look for an adjustable butt stock.
I'm a big fan of wood stocks over synthetic, but that's because I'm willing to trade lightweight for a more solid feel. But that's just me. Ultimately, which stock you pick is totally a matter of personal preference, and I would strongly recommend you hold as many different styles as possible before you spend the money on one.
The trigger is gone into in great depth elsewhere on this site, so this will be brief. In my opinion, the only thing a trigger really NEEDS to do is not be noticed. On the factory Ruger 10/22, it is heavy, rough, and still somehow sloppy. It's noticeable, and while some people will argue that you just need to learn how to shoot with it, I don't feel the need to put up with it. Does this mean I need to get a $300 Kidd Custom group? No, although I hear they are fantastic! If I do a basic trigger job, it might not be perfect, but it will be good enough that it's not distracting when I shoot, and it's not pulling my point of aim off.
There is the issue of overtravel. It's the distance the trigger travels between when it 'breaks, and ultimately stops, usually by slamming into some part of the trigger guard. Very sloppy. The theory goes that by the time the trigger smacks into the trigger guard the bullet is already half way down the barrel, and that 'bump' will move the point of aim slightly. An overtravel stop does just that, it stops the travel the instant the hammer is released. The idea is that there is no real momentum built up, the bullet hasn't even started moving yet, and the point of aim is unaffected. A well tuned overtravel stop can not only improve accuracy, but it also make the trigger feel awesome!
There are a number of little things you can do to improve accuracy, but they are really beyond the level we are aiming for here. Things like pinning the firing pin to create more constant firing pin strikes will result in such a minor accuracy improvement that you may never actually be able to prove it did anything And that's really the key here. Decide what you want to do. If you enjoy tinkering with your rifle, go for it! Do all that little stuff. But if you are more interested in hitting your target than bragging about your gun, do the big stuff, then buy 2,000 rounds of ammo. Break in your new barrel nicely, then clean it every couple hundred rounds. Burn through that 2,000 in a month or two. When you are done, two things will have happened. First, after spending some real time with your rifle you will have a solid idea of what you want to do, or what you want to change. And second, you will see a greater improvement in accuracy than spending three times that amount on little parts.