Shoot better: part 1.
First, it's helpful to understand the difference between precision and accuracy. I once got in a somewhat contentious debate with a local gun writer about the distinction. He was misusing the terms, and when I called him on it he got very defensive. He shouldn't have, because a lot of folks don't know the difference.
Anyway, accuracy is a measure of how close your result is compared to an expected result. For example, how close your shot is to the center of the bull's-eye. Precision is a measure of repeatability, such as how tight your groups are, regardless of where they hit the target. Your ultimate goal is to achieve both, which is usually best accomplished by working first on precision, which begins with your equipment.
Start with a visual inspection to ensure everything on your crossbow is in good working order. Check nuts, bolts, screws and fasteners for tightness and fix if and where necessary. While you're at it, look for any damaged, defective, misaligned or non-symmetrical parts. Make sure limbs are properly aligned and seated in limb pockets, especially split limbs. Look at your bow from the side to confirm that wheels are parallel with the rail and not canted.
Manufacturers do their best to ensure quality, but with any mass-produced item there is always the possibility of problems. An air bubble in the extrusion process, a power surge during machining or a moment of inattentiveness on the assembly line could all lead to less-than-desirable results in the product and the way it ultimately performs.
The issue could also be your fault. Men, especially, tend to dismiss manuals. Don't. Read and follow the owner's manual precisely when assembling your bow. I learned this the hard way. After struggling for quite some time to attach the limb assembly to a crossbow, I finally reverted to the manual and discovered I was supposed to back out two small setscrews in the stock before tightening the main riser bolt.
Fortunately, crossbow makers back up their products with warranties. So, if there is a defect or other issue that's their fault, they'll fix or replace it. If it's your fault (you assembled or used it improperly), take it to the local pro shop and get it fixed.
Now turn your attention to the other major component of your shooting system--the bolt. Step one, before you inspect the shaft, vanes, nock and tips for potential problems, is to make sure you are in fact using the proper components. For bolt length, you have a choice of 20- or 22-inch shafts. Never shoot less than the recommended length, though you can go longer. In fact, there are advantages to the longer shafts that can enhance accuracy and precision.
Next, you have to pick the optimal shaft spine/weight. As you're probably aware, the reason there are so many more choices in arrow spines for compound shooters is because variables such as draw weight, draw length, arrow length and tip weight all influence dynamic spine--the flexing of the arrow at the shot. Because a crossbow bolt lies on, and in direct contact with, a ,rail for its entire length, that's much less of a factor. In fact, some bolt manufacturers don't even list a spine rating, instead grouping various shafts only by weight.
Theoretically, you can't go wrong using the shafts that came with your crossbow. When it comes time to replace or supplement them, consult the owner's manual and/or shaft selection guide. However, if you're looking to improve performance with different shafts, there are several things to consider.
One is weight. As with shaft length, it's better to err on the high side. While most crossbows will shoot most bolts just fine, it might be better (and safer) to shoot heavier, stronger shafts with heavier draw weights. And according to the folks at TenPoint, heavier shafts produce the quietest and most vibration-free shot, are more stable in flight and shoot tighter groups down range. You give up a little speed and flatness in trajectory, but the sacrifice might be worth it.
Precision applies to manufacturing as well as performance in the field. In fact, the two are interrelated. And that's another reason why you might want to consider forking over a few extra bucks for high performance carbon shafts. As with compound arrows, more expensive crossbow bolts have better straightness tolerances and other features. For example, Carbon Express' Maxima Hunter Crossbolts are laser-checked for straightness to a remarkable .0001-inch and are constructed with BuffTuff Plus carbon weave for superior strength and accuracy. Similarly, Bloodsport's Witness bolts have a straightness tolerance of .003-inch, and the patented Blood Ring technology--a white band that helps you identify the type and location of hit.
To my knowledge (and that of numerous sources I consulted), vane length is largely a matter of personal preference or using whatever was supplied with your crossbow. Still, it can't hurt to experiment a little as you might find one type--short or long--works better in your particular bow.
That gets us off to a good start, but there's plenty more you can do to your crossbow to maximize its performance. We'll look at a few more in the next installment, and then move on to what you can do to improve your own shooting form.
Tip of the Month
Spin test all your bolts. Roll them on a flat surface or, better yet, an arrow spinner and look for wobbling. Often you can remedy wobbles by heating and re-seating inserts or nocks or switching heads. If that doesn't work, mark the bolt and consider relegating it to discharge status.