I got a few questions about arrows even after reading a bunch of threads over at archerytalk and thought I would ask the same over here. I have just recently ordered a Bowtech Assassin from my local pro shop. My DL is 26.5 and I plan on having my bow set at 52lbs. I mainly plan on using the stick and string for hunting and target practice in the back yard, might try my hand at 3D, but not sure. My next step is finding the right carbon fiber arrows and my questions are these:

Why is arrow length important? Can't I just shoot them straight out of the box no matter what the length is?

I dont understand a thing about size. please explain. I'm thinking this is diameter of the shaft?

Grain, I understand a little about this from shooting, but I know arrows are an entirely different thing. What are the pros and cons of lighter vs. heavier?

Field tips vs. broadheads. Obviously I'll be using broadheads for hunting, but I want to use field tips for the target/practice. I would think it reasonable to use the same grain field tip for practice as broad head is to hunt. And I dont want to be screwing up a practice target or the arrows using broadheads for practice. The thing is I have heard "practice with what you hunt with." I'm sure there is a debate about this some where. I'm sure that broadheads fly a bit differently than field tips.

Thanks

Arrow length is important for a couple reasons. A shorter arrow will behave stiffer than a longer arrow. OTOH it is dangerous to have an arrow too short, it could fall off the rest before you release and you could have a catastrophic failure.

The sizes are based on stiffness, the amount an arrow bends under load (on a standard test setup), or "spine." Typical stiffness ratings are 0.400, 0.340, 0.300 etc. Every manufacturer has a naming convention that may be different from the spine measurement. The arrows might be labeled 4560 or 5575 meaning in general that they are for bows 45-60 lbs in draw weight or 55-75 lbs in draw weight. However, this is not always true and you need to check the arrow manufacturer's chart to be sure. it is important to match the appropriate arrow stiffness with your desired setup. The diameter of the shafts may vary between product lines.

If you were to shoot a full length arrow from the package, you probably would have to buy a stiffer arrow than if you cut it to be 1" past your rest at full draw.

Generally, lighter arrows shoot faster with a flatter trajectory, heavier arrows have better penetration.