by Joni Marie Kiser
“I want to buy a bow and get into archery, but I don’t even know where to begin.” I hear this all the time from customers who come in to my archery shop. Reading the specs on a bow, or hearing someone go over the details of it, can be like listening to a foreign language if you don’t know what some of the acronyms and terminology mean. Here are some basic terms and definitions that can make that process a little bit less intimidating.
Draw Length on a compound bow refers to the distance that you draw a bow back until it stops where it reaches your appropriate anchor point (consistent point that you come to in order to begin to aim the bow). On a compound bow this is a very important measurement, unique to you, to be sure that the bow fits you properly. There are some easy ways to get a measurement of draw length. One of the simplest versions is to stretch out your arms at your sides, parallel to the ground. You then have someone measure from the tip of your middle finger on one side, over to the tip of your middle finger on the other side. This gives you your overall wingspan and then you divide this number by 2.5. This will give you a relative idea of your draw length. This method is not perfect; but it will give you a good starting point and you will likely be within an inch of that number depending on what bow you choose. Draw length can vary a bit based upon the type of bow you choose; so in the end – the bow you pick must be fitted appropriately to you. The shop that sets it up for you will make sure that your front arm is not over extended when you are at full draw, that you are not “bunched up” trying to get your nose to the anchor point on the string and that your back elbow is extended properly and level. Going to buy a bow and having a rough idea of what your draw length may be can be helpful however, so that you can ask which bows can be adjusted to your draw. There are some bows that are cam or module specific bows, meaning in order to make them another draw length you need to put a different cam or module on them to change the draw. Others have sliding modules on them so that they can be changed to any draw length. If you have an idea up front of what draw you might be, it can be helpful for you to narrow down which bows may not work for you.
Axle to Axle
The axle to axle length on a bow refers to the measurement from the center axle of the top cam to the center of the bottom cam. If it is a solo cam bow then this would be from the center of the idler wheel to the center of the bottom cam. How do you know what a good length would be for you? Hunting bows have gotten shorter over the years overall; the limbs are more parallel than they used to be and they are more compact. The majority of hunting bows now range from 28-35 inches in axle to axle length. Bows that are used just for competition shooting are generally longer axle to axle and could be anywhere from 34-40+ inches in length. This is because a longer bow gives you more stability overall. A longer bow is heavier, thus often ruling it out for some hunters who are trying to shave off weight that they have to pack in. The length of the bow can also have some effect on the “forgiveness” of it. A longer bow can be more accurate because of the angle of the string at full draw. If you imagine pulling back a long bow to a 28 inch draw length and then imagine pulling back a short bow to a 28 draw length; the shorter bow will have a much more severe V or string angle at full draw. A deeply angled V can create what is referred to as “nock pinch” and can produce more human input on the arrow itself when it is released; therefore making it less forgiving. A long bow would have a very wide V and would not pinch the nock so much, therefore making it easier to be accurate with. This all becomes more of a concern the longer your draw is. I have a short draw length of 25 inches. There is much less chance of this being an issue for me on a bow, because I don’t pull it back as far. A man who is over 6 foot tall and has a 30 inch draw however, pulls the bow 5 more inches than I do, and a short bow will get a very severe string angle in the back for him, creating much more nock pinch than I have. If you have a long draw length, the axle to axle length of a bow can be more of a concern when shopping for a bow.
The measurement of brace height is from the throat of the grip of the bow back to the resting point of the bowstring. Brace heights can measure from 5-8 inches roughly on most bows. A short brace height bow is going to be faster, but less forgiving to shoot. A long brace height bow is going to be slower, but more forgiving to shoot. Most hunters choose something in the middle with a 6-7 inch brace height in order to get decent speed with some forgiveness. An easy way to think about brace height is to think about how long the arrow is on the string. If you are shooting a 5 inch brace height bow; when you pull it all the way back, the arrow stays on the string for a longer period of time until it comes to its resting point – 5 inches from the grip of the bow. Therefore the arrow is faster, it was on the string longer being pushed forward. It is also less forgiving because since it was on the string longer, there is more time for you to have human input on the flight of the arrow before it leaves the bowstring. Generally bows with 8+ inch brace heights are used as competition bows due to their higher level of accuracy but slower speed.
Speed: ATA and IBO
Bows have gotten faster and faster over the years. Most hunting bows now can go from 310 ft per second up to 360+ Any bow rated over 310 ft per second is plenty fast enough to take down anything you would choose to shoot. There are 2 different speed ratings on bows. ATA and IBO. ATA ratings are set and are taken at a 30 inch draw, 70# draw weight and with an arrow weighing 5 grains per pound of draw weight (350 grain arrow). This allows you to compare, apples to apples, different bow brands to see which are faster. Are you actually going to hit these ATA rated speeds yourself? No. Its important to understand that the rating is there so that you can compare bows accurately, however unless you are exactly a 30 inch draw and shooting the same set up – you are not going to attain that exact speed. A 350 grain arrow is very light and is one step away from a Dry Fire (shooting the bow with no arrow in it). Why would companies use such a lightweight arrow to rate their bows? To give them the best possible speed rating! You would never actually hunt with such a light arrow because you would get nothing more than a superficial stick into an animal. An arrow that is heavier is going to carry more energy behind it and once it impacts, its going to carry that momentum forward to pass through the animal. An IBO rating on a bow is similar to ATA but it is not as predictable. To do an IBO rating companies are allowed to use 80# instead of 70# and they may use a 31 inch draw rather than a 30. Unfortunately this can inflate the speed numbers of bows rated only on IBO. There is a lot of talk in the industry about making all companies use ATA in order to be fair, but so far it has only been talk. If you have an IBO rating on a bow and you are comparing it to an ATA rated bow, keep this in mind. So why might you want a faster bow? More speed gives you a longer effective range to shoot. You have less drop in your arrow trajectory and you have less wind drift. Most bowhunters agree, depending on their bow set up that they are comfortable that they can take an ethical shot between 20-50 yards or so. There are a few individuals that feel confident out as far as 70-80 yards as well. Its important to practice out father than you would actually shoot in a hunting situation and to know your accuracy at different distances and in different conditions. Now that being said, taking a 100 yard shot is possible with many of todays bows at their top speeds and it is a lot of fun. However you would not ethically take that shot on an animal. But shooting long distance in 3D Archery competition etc… can be a lot of fun and can increase your confidence in judging distances and calculating for variations.
If you are planning on hunting with your bow, it is important to know the hunting regulations on draw weight. For many animals in Alaska like Black Bear, Deer, Caribou, Sheep etc… the legal limit is 40# or more. For thicker skinned animals like Goat, Moose, Brown Bear and Musk Ox the legal limit is 50#. It is important to be sure that it will adjust to a weight that meets and exceeds these limits. I find most female new shooters start up about 35# or so. The more that they shoot, the more their strength increases over time and they will adjust their weight up. It is rare that I see women who shoot too much over 50#. On a good bow at 50# of draw weight you have plenty of speed to get a pass through on any animal you choose, as long as you are making shots within your ethical distance range for your speed. I have taken Brown and Black Bears, Alligator, Moose, Wart Hogs etc… which are all thick skinned animals – with a 52# draw weight and have always had pass throughs. I know what my distance limits are for shooting my draw weight and I will not shoot an animal beyond that. The bows are so much faster today than they used to be. My 52# Mathews bow is faster than many of the older bows were at 70#. Most men that come through the shop shoot bows from 50-70# of draw weight. Depending on what is comfortable for them, whether they have had shoulder trouble etc… will determine where they settle in and are comfortable. It is important when you are picking out your bow to be sure what the low and high ends of the draw weight are on it. There are some beginner bows out there that go from 15-70#. This gives you a huge range of adjustability and can be very appealing to beginners who are not sure where they will end up settling in. These adjustable bows (such as the Hoyt Ignite or Mission Craze 2) almost always also have large adjustable draw ranges, making them easy to fit to anyone. However because of their larger adjustable ranges you do sacrifice some speed in a less efficient cam system. They also tend to be shorter axle to axle bows and therefore are not as forgiving to shoot.
Having an understanding of some of this terminology can be very helpful when reading about bows or when visiting shops to look at what is available. There are lots of other variations in bows such as the material that the riser is made out of; whether it is cast, machined aluminum or carbon etc… These can have an effect on the way the bow feels, how heavy it is and how much vibration and noise you experience after the shot. The best bet, once you read about a variety of bows and narrowed down what you are looking for, is to visit your local Pro Shop and try out some models. The grip, the weight of the bow, the draw cycle and the shot – all feel different brand to brand. You will start to tune in on what feels right for you. Ultimately, it is all about what feels the best to you and what you are going to enjoy shooting the most! Once you are all set up on a bow and it has been customized to fit you – you will want something that you can shoot throughout the year for fun – not just during hunting season! With a bow, you get to pull your ammo back out of the target and reuse it! Making it fun and inexpensive to use year round!
Joni Kiser is Co-Owner of Full Curl Archery in Anchorage. She is a National Factory Pro Staff for Mathews Archery and HHA, a Field Staff for Prois and has harvested a large variety of big game animals with her bow.