Mon 5 Feb 2007
I shoot Easton AC Super Slim 400 arrows fletched with 2.5-inch vanes having 7 degrees of helical offset and tipped with 100-grain broadheads. My arrow specifications are the result of many years of intense competition and demanding bowhunting. An entire summer 3-D season or fall hunting season often comes down to just one or two shots - one arrow for all the marbles. After investing all that time and money, I will only trust the very best arrows on the market.
I can back up all my arrow choices with test data from both formal and informal sources. As I said, I didn’t come by my arrow selection without considerable time and testing. Here is why I prefer Easton’s aluminum carbon composite arrows.
WIND DRIFT
AC super Slim arrows are roughly .265 inches in diameter. Compare that to roughly .375 inches for a popular 2413 aluminum arrow or the large diameter carbon arrow shafts. From the side, a 30 inch Super Slim has a side surface area of 7.95 square inches. The 2413 has a side surface area of roughly 11.25 square inches – 1.4 times more than the Super Slim.
In my hands a smaller diameter shaft requires less fletching to stabilize it’s flight. Smaller fletching reduces the side surface area even further. When you shoot small diameter carbon arrows in a crosswind, they exhibit less sideways drift than larger diameter arrows. This is because there is less surface area against which the wind can bear.
By reducing wind drift under challenging conditions, you make your arrows more forgiving of aim point errors and changes in weather conditions. In other words, if you forget to account for wind speed, these smaller diameter arrows are likely to bail you out under typical bowhunting conditions.
The difference is substantial. By switching from large diameter aluminum arrows to small diameter carbon composite or all-carbon arrows with smaller fletching, you can literally cut your wind drift by more than one half.
Wind drift is a larger concern for western hunters than for eastern hunters. However, even in wooded settings (where trees partially break the wind) you need to allow for some arrow drift when the crosswind exceeds 5 to 10 mph. A small diameter arrow is more likely to save the shot if you forget this last second adjustment.
DOWNRANGE ARROW SPEED
In 1993, AFC Carbon Arrows of Chatfield, MN (the company is no longer selling arrows) completed an independently verified test of penetration and downrange loss of arrow speed. The tests compared the qualities of both small diameter carbon arrows and typical aluminum arrows of the same weight. Though the testing did not include ACC arrows, the results are still enlightening because the carbon arrows used in the test were close in diameter to AC Super Slims.
Due to friction with the air, arrows slow down the farther they get from the bow. The greater the surface area of an arrow, the faster it slows down. At 40 yards, AFC’s testing showed that the carbon arrow lost 7% of its initial speed while a 2312 (of the same weight) lost 8.4% of its initial speed. The test only went out to 40 yards, but I know from my own testing that the difference between aluminum and carbon arrows begins to increase even faster beyond 40 yards. This is roughly the amount of difference you would find between Super Slims and popular aluminum or large diameter carbon arrows. Granted, this is not a huge difference, but this is a tough game and I’ll take every advantage I can get.
IMPROVED PENETRATION
The carbon shaft in the test cited in the previous section weighed 493 grains. It penetrated more than 40% deeper into both Ethafoam and silica sand than the aluminum 2312 (which weighed 494 grains) against which it was compared. That is an astonishing advantage for the smaller diameter arrow.
I also recently studied data from a test conducted by Outdoor writer Bill Winke and his father. They designed the test to measure broadhead penetration, but it also shed some light on penetration issues related to arrow selection. The carbon shafts were internal component models including the Beman ICS Hunter 340 at 319 grains (without the head) and Carbon Express 400 with 3 grains per inch weight tubes at 389 grains total (without the head). The aluminum shaft was again the 2312 this time at 367 grains (without the head).
The data revealed that both carbon arrows did measurably better than the aluminum (even though one weighed considerably less) penetrating roughly 15 to 25% deeper depending on the arrow and the backstop.
Diameter appears to be the greatest reason that carbon shafts do so well in these tests. As the diameter goes down so does the surface area - reducing friction and resistance as the shaft slips into the target. The outside diameters of the two shafts tested in 1993 were .233 inch for carbon and .360 inch for the 2312. As I already stated, AC Super Slims have an outside diameter of roughly .265 inches.
Some will argue that any testing in solid testing media will never simulate live animal tissue. I can’t argue with them. But the numbers and my own experiences are so compelling that they can’t be ignored. It is my firm position that smaller diameter carbon arrows such as the Super Slims penetrate better than large diameter arrows of the same weight.
On a side note, some carbon arrow experts believe that the stiffness of carbon arrows aids in their penetration advantage. They have the ability to dampen out vibration quickly on impact, possibly directing more kinetic energy down the centerline of the shaft where it does the most good. While I don’t have any direct testing to support this view, I have found a different reason to prefer stiff arrows. My arrow groups tighten up measurably when I shoot arrows that are slightly “stiff” for my draw weight and draw length. It is certainly worth considering this option if you use a release aid.
FLETCHINGS PRODUCE STABILITY
When you stuff arrows into a small, shafts-touching circle in your backyard target, you increase your confidence and your readiness for the hunt, but you actually diminish the quality of your arrows. Repeatedly smashing and slapping your arrows together in the target will cause weak spots, slight bends and skewed nocks. Often, these disturbances are minor and not evident to the eye, yet they cause inconsistent accuracy.
An arrow needs to spin to reduce the affect of these small inconsistencies. It’s important to note that even arrows equipped with field points will plane if they come out of the bow other than dead straight. You need a high degree of helical offset to stabilize your arrows quickly and keep them from wandering. I apply the most helical offset my fletching jig will allow while still creating proper adhesion. Easton’s experts recommend five to seven degrees, for most situations. Few bowhunters carry a protractor in their tackle box, so just max out your jig and you will achieve the desired results.
Large doses of helical offset once created tuning problems because the fletching inevitably contacted the rest and kicked the arrow off line. Today’s drop-away arrow rests eliminate this problem and I heartily recommend them with aggressive helical fletched arrows.
CONSISTENT CONSTRUCTION
So far, I have built my case for small diameter carbon arrows. Now I’m going to take my argument one step farther and show you why I choose Easton’s AC Super Slim arrows over all other carbon shafts.
I realize that aluminum carbon composite arrows are among the most expensive arrows on the market but they are well worth it. The processes used to make ACC’s (and Beman Carbon Metal Matrix shafts, too for that matter) are much more painstaking than those used to make other carbon arrow styles. This lengthy process demands respect among serious bowhunters – and a higher price tag.
Easton starts with a small aluminum core tube having a .007-inch wall thickness. Easton has a very precise process for straightening aluminum tubes (arrow shafts) and this one is straight to within +/- .002 inch. This makes ACC’s among the straightest shafts on the market.
After straightening the core tube, the technicians apply a layer of longitudinal carbon fibers over the tube. Carbon cannot be straightened, but since the carbon covers a super-straight aluminum tube, no straightening is needed. The finished arrow takes the straightness of the aluminum tube but possess the strength, stiffness and durability of carbon. ACC shafts (and all other aluminum carbon composite shafts) have the potential to possess the best attributes of carbon and the best attributes of aluminum.
A very tight straightness tolerance is just one small aspect of the ACC and AC Super Slam’s consistency. Because of the core tube and ability to grind the outside wall of the shaft with a center-less grinder, these arrows have very precise wall thickness and diameter measurements. There is no seam or egg-shape to these carbon arrows as can occur with some carbon models. You don’t have to float them in your bathtub to find the “high spot” or roll them on a table like you would the tip section of a fly rod blank to find the stiff side. There isn’t a high spot or a stiff side; they are perfectly uniform - the most uniform arrows on the market that are still practical for bowhunters.
ACC’s give you consistent straightness, consistent weight (within +/- .5 grains per dozen) and consistent spine. Not only that, but they accept internal components and exhibit all the best qualities of improved penetration, reduced wind drift and increased down range velocity.
I own a shooting machine and have done quite a bit of arrow testing. The AC Superslims and ACCs group consistently better out-of-the-box than any other arrow I have experimented with. That’s why I shoot Easton AC super Slim arrows.
Sidebar: Number Your Arrows
Arrows take a beating when you practice with them for several weeks. They slap and clatter together until their straightness and spine tolerances degrade. The small variations between arrows that result from common wear and tear will influence your accuracy.
Start with a dozen arrows. Ideally, they are brand new, but if you can’t afford to buy a fresh dozen, at least spring for six new shafts. Number each arrow. Start with a clean target and put field points on your arrows. Shoot all of them at the paper at your maximum accurate range. Don’t pay any attention to the numbers on the arrows before you shoot them. In fact, make a conscious effort not to look at them so you won’t bias the test. When you go to pull the arrows, write the corresponding number next to each hole.
Shoot every arrow at least six times and then look at the target to see what patterns are forming. You will likely have an arrow or twothat consistently fly wide of the mark. Typically, I find that the vast majority of my arrows fly close to the same hole though a few might hit too far from the center to be acceptable. This is where a shooting machine really earns its keep. Target shooters, in particular, will benefit from this level of arrow-to-arrow consistency. However, bowhunters will too when the differences uncovered are great enough. Obviously, I rotate the nock on the loose grouping arrows and shoot them again until they come in to the group. If I can’t get them to group, I pull them out of my quiver before the season.
Sidebar: Comparing Arrow Drift to Wind Speed and Direction
As a rough indication of wind speed and direction, drop a handful of two to three-inch tufts of grass at arm’s length from roughly the height of your belly button. For every 10 mph of wind speed, the clippings will drift three feet before hitting the ground. It is a rough gauge, but this indicator will serve as a reference to compare your practice conditions to your hunting conditions. Also, if the wind is not a direct crosswind it won’t cause the arrow to drift as much as if it were perpendicular to the direction of the shot. Account for this both when practicing and when shooting at game.
As I already stated, small diameter arrows with modest fletching drift less in a crosswind than larger diameter arrows, but they do drift, and you need to account for wind drift when confronted with a shot across windswept, open settings.
Sidebar: The Proper Balance Point
Your arrow’s balance point will affect its trajectory and stability inversely. For example, an arrow that is “tip light” will remain a little more level in flight and will actually plane or sail along a flatter trajectory than one of the same weight but with a heavier nose. But, tip light arrows don’t correct quite as quickly when they come out of the bow. The closer the arrow’s center of gravity (balance point) gets to its measured center the less stable the arrow will be in flight.
The AC Super Slim arrows that I prefer balance very well with a 100 grain point and 2 1/2-inch vanes, producing a balance point that is right in the ideal sweet spot for a hunting arrow of roughly 10% forward of center.