May 26, 2021
By Bob Humphrey
Trends are common in the archery world. They’re driven by manufacturers responding to consumer requests, advancements in new technology or a change in direction when the limits of existing technology or physics are reached. Often, it’s some combination thereof.
A couple recent trends in crossbows involve speed and size. In this case, the challenge is increasing one while reducing the other; no easy task, as the two tend to be inversely correlated. The easiest way to boost speed is to increase power stroke and limb length. Consumers, however, have made it clear they want more compact crossbows, and the industry has gone to great lengths to make bows shorter and narrower while still increasing speeds. Neither trend is new; they’ve just been emphasized more recently.
Rise of the Compact Crossbows
The first appreciable narrowing came, somewhat unintentionally, with the introduction of Scorpyd’s reverse-limb technology. In addition to better balance and a quieter, smoother shot, the original model boasted an axle-to-axle width of 16¾ inches, compared to an average of around 22 inches at the time. One of the first forward-limb bows with a noticeable narrowing was TenPoint’s Vapor, 17½ inches wide at rest but a meager 123⁄5 inches when cocked. Others such as Carbon Express, Barnett, Bear and Killer Instinct followed suit. Excalibur even managed to slim down recurves with its Micro series.
The next milestone came from Ravin — the company’s HeliCoil Technology helped it create an ultra-compact, 6-inch width. Other bows from the likes of CenterPoint and Horton were down in the low teens, with the rest of the pack at or below 20 inches. The sub-compacts had arrived, and the field was filled the following year with examples such as Mission’s 10-inch-wide SUB-1 and TenPoint’s 6-inch-wide Stealth.
Increasing Bolt Speeds
In 2011, average speed for new crossbows was around 330 fps, with a few exceptional “speed” bows from Scorpyd, Stryker and Inferno in the 375-385 fps range. Five years later, the average was up to around 360 fps, but the field was full of bows in the high 300s, with models from Barnett, Darton, Excalibur, Scorpyd and TenPoint at or above 400 fps. By 2020, crossbow manufacturers made 400 fps almost a standard — Ravin’s R29X boasted 450 fps, topped by TenPoint’s Vapor RS470 at 470 fps — and they did it without sacrificing smaller size.
While similar technology existed at the time, Scorpyd’s Jim Kempf was the first to introduce the reverse-limb technology on this side of The Pond. That, combined with a system where the string goes behind the riser and off the front of the cam, maximizes a shorter power stroke rather than using a longer one to produce more speed. The end result was, until recently, an industry-leading 480 fps from a 13-inch width.
TenPoint’s Narrow Crossbow Technology (NXT) bow assembly uses several physical advantages. A maximum rotation cam system takes full advantage of eccentrics. Extra-strong Dual Flex limbs are mounted in a Tri-Lock pocket system for added structural strength. Then the Vector Quad Cable system runs cables from a riser attachment through turnbuckles on either side of the barrel to grooves around the cam axles, instead of passing them beneath the barrel. This helped TenPoint achieve 400 fps at less than 6 inches of width. This year’s models combine NXT with reverse-limb configuration for 470 fps at 6½ inches wide.
Ravin made quite a splash when it brought its HeliCoil technology to market. As the name implies, it coils cables away from both the top and bottom of the cams in helical grooves. This allows for 340 degrees of rotation while keeping the cams level and balanced. The Frictionless Flight System also allows both string and bolt to float above the rail, resulting in a speed of 450 fps from a crossbow that’s only 6 inches wide.
Barnett took a slightly different approach by borrowing another recent trend from the compound side. Its Hyperflite series crossbows use a proprietary .204 micro-diameter Hyperflite bolt. The bolt’s 21 percent FOC increase and 61 percent greater ballistic coefficient reduce wind drift, increase downrange accuracy and purportedly increase penetration by up to 22 percent.
Crossbows have been getting shorter as well, also no easy task given the importance of power stroke. Average length in 2011 was 3 feet. Today it’s somewhere between 3 and 6 inches shorter, depending on the bow. A big contributor to overall length is the stirrup. Barnett addressed that by incorporating it into a step-through riser, effectively eliminating 6 inches or more of length. Darton was among the first to incorporate a shorter bullpup-style stock, followed soon after by the likes of Carbon Express, Stryker and a subsequent spate of tactical stock bows. Along with this came the ability to move the latch mechanism well back, in extreme cases such as the Ravin R25 and Darton Toxin series, to the rear of the stock. These innovations, along with the aforementioned technical advancements, allowed for shorter overall length without reducing power stroke.
Where and when will it end? Earlier this year, Ravin announced its new R500 Series capable of launching 400-grain bolts 500 fps thanks to the company’s proprietary HexCoil Cam System. What’s even more impressive is that the bows feature a compact frame, coming in at 28 inches long and just over 3.6 inches wide axle-to-axle when cocked.
Some engineers say we’re nearing the physical limits for making bows faster while ensuring safety and reliability. There’s still room for width reduction, but even that is skirting the law of diminishing returns. A better question might be: What is the next big trend? Time will tell.
Tip of the Month
Changing the magnification on an adjustable scope changes the relative distance between reticles or dots. Newer scopes designed for speed bows are usually calibrated by speed rather than power on the dial. If yours isn’t, you can “dial in” downrange accuracy with practice on the range. First, sight in your top reticle or dot for 20 yards. Then, dial in your 40-yard reticle — usually the third from the top — at 40 yards. The other distances should now be good, but it’s best to go back and verify 20 yards and confirm longer ranges.