Can't ignore you. You asked a question and will get some answers. That's one way of learning.

Being as the number confuse you I'll explain a little further. When we talk about the spine of an arrow we are talking about how much bend it is rated for. The spine is figured with a 29" arrow placed on two points 28" apart. Then a two pound (actually 1.94 lb) weight is suspended in the middle which makes the arrow bend down. This bend is measured witha dial in thousandths of an inch. Thus the number such as .500 or .300". Most people just forget the decimal point.

As you can see, an arrow with a smaller number bends less so is stiffer. The longer the arrow and/or the higher the draw weight the stiffer an arrow has to be to fly well. Determining what you should shoot is why arrow spine charts are given by manufacturers. To give you a guideline of where to start.

Where you have to be careful is when looking at the numbers posted by different manufacturers. They don't all use the same numbering system. Easton/Beman use the actual spine deflection to number theirs as does GT with their Ultralites. Companies such as Carbon Express use a different numbering system. They rate theirs with numbers like 100, 200, 300 and so forth, with the higher sumber being the stiffer arrow. They also have their Maxima series that are numbered 250 and 350, again 350 being stiffer than 250. Just backwards from Easton/Beman.

Companies such as Blackhawk number them similar to Carbon Express except that they add another zero, thus 2000, 3000 and so forth. Quite confusing, isn't it? It sucks for the average guy. And shops don't always steer you toward the right arrow.

There are other factors such as cam style that enter into the equation, but for a newbie this isn't all that important.Hard cam bows exert more energy on the arrow so require a slightly stiffer arrow than a bow with medium or soft cam. Most cams today are of the HARD variety and you won't be far off the mark by picking arrows accordingly.

Now let's assume that you, being fairly new, get into this archery thing. You want a 30" arrow for a 30" draw and 60#, with hopes of upping the poundage over time. The shop sets you up with something like a 400 spine or 340 spine (340 being the right one). The problem is, as you jump up in draw weight these are no longer properly spined for your bow. You, of course, are wondering why your arrows won't fly well with broadheads any more. Well, that's becasue the arrows are bending too much coming out of the bow, causing wind planing by the blades. Sooner or later, after much frustration, you ask what's going on and figure the shop sold you the wrong arrows. Not so. They had it right in the beginning. Long story short---if you plan on going from 60# to 70# then buy arrows for 70# and be done with it. They will be a little stiff in the beginning, but that's better than to light in spine.

And another thing. Don't get all hung up on the poundage thing. Just becasue a bow goes to 70# doesn't mean that's where you have to shoot it. Part of tuning the equipment may mean adjusting the weight of the bow accordingly to get best arrow flight. If you have a particular arrow and it won't fly well and you find that by backing down from 70# to 65# makes it work then so be it. That's why bows are adjustable. Don't let your ego get in the way. No animal walking the planet can tell that 5# difference. And don't let a little speed drop sway you either. A fast arrow that is hitting the animal half sideways doesn't penetrate as well as one flying true from less poundage. Something else is that by adjusting the limb bolts you can really fine tune things, and there is no monetary cost involved such as spending money on new arrows and/or different broadheads, fletching, and all that other stuff.

Well, I got a bit long winded here, but I hope this helps you understand things a bit more clearly. Now that you are totally confused, go shoot your bow and have fun.

Barry