What is F.O.C.? And how does it affect my arrows?

F.O.C. is a hot topic in arrow-building discussions today.

What is F.O.C.?

It’s the acronym for “front of center.” What it refers to is the percentage of an arrow’s total weight – including the point – that is concentrated forward of the center of the arrow.

F.O.C. is something that mainly bowhunters are concerned with, and there’s no question that having a solid F.O.C. number is key to getting good arrow penetration on a big game animal.

But some bowhunters think F.O.C. is the only factor they should be concerned with in preparing hunting arrows, and they don’t understand the consequences of simply beefing up the front end of their arrows.

Let’s start with a minimum. Easton Archery recommends arrows have a minimum F.O.C. of 10-15 percent. That’s going to allow an arrow to fly accurately, especially at longer distances. If you go less than 10 percent, the arrow’s trajectory will be flatter, but its flight will be more erratic.

That 10-15 percent is what Easton recommends for target arrows and for hunting arrows. The amount of weight needed up front to hit that range will be sufficient for hunting, according to Easton.

A lot of bowhunters today try to get their F.O.C. to 20 percent and even a little higher. They can do that by adding weight to their inserts. A standard aluminum insert might weigh about 16 grains, where there are brass inserts that can weigh 100 grains. Also, some insert manufacturers allow weights to be screwed into the backs of their inserts, which is another way to add weight to the inserts.

Gold Tip 100-grain brass insert

Bowhunters also can add weight by shooting heavier broadheads. A standard broadhead weighs 100 grains. But there are common options for 125 and 150 grains. And there are special broadheads aimed primarily at the heavy F.O.C. fans that weigh 200 grains.

Strickland’s Archery 200-grain broadhead

So if a bowhunter swaps out that 16-grain aluminum insert for a 100-grain brass insert, and trades a 100-grain broadhead for a 150-grain model, that hunter just increased the front-end weight of that arrow by 134 grains. That’s sure to boost the arrow’s F.O.C. considerably.

No question that arrow now will have improved penetration capabilities. But it also could cause problems for the bowhunter.

For starters, with all that weight added to the front of the arrow, the arrow’s spine is considerably weakened, and accuracy problems are likely. According to Easton’s hunting arrow shaft selection chart, an archer shooting a 29-inch arrow from a 62-pound bow should choose an arrow with a 340 spine while using a 100-grain broadhead. If the archer only increases point weight by 50 grains, that archer should be shooting a 300-spine arrow. The more weight you add to the front of an arrow, the stiffer that arrow needs to be to support that extra weight.

A second issue could be trajectory. When you add weight to an arrow, you slow it down, which adds more curve to its trajectory arc. For the Eastern tree stand hunter who expects most shots to be under 20 yards, that’s probably not an issue. But it could be for the Western hunter who is spotting and stalking and might have to shoot out to 60 yards. With that much weight added, a 2-yard miscalculation in shooting distance could easily result in a miss.

No question there are benefits to boosting an arrow’s F.O.C. to increase its capability of punching through an animal. Some animal hides are notoriously tough, and if the arrow hits a bone, it would be nice if the arrow could punch through that bone.

But as with many things in archery, balance is important. Kinetic energy is the amount of energy a body has in motion. It’s calculated by a formula that relies on the weight and speed of a moving object.

To calculate KE in foot pounds you would take the arrow weight and multiple it by the velocity squared, and divide that number by 450,800. For hunting game animals like antelope and deer, Easton recommends an arrow have KE values of 25-41 foot pounds. For elk, black bear and boar, Easton recommends 42-65 foot pounds.

To illustrate what an arrow build would be to meet those minimums, let’s look at the popular Easton Axis 5mm. A 29-inch, 340-spine arrow weighing 9.5 grains per inch, with a standard insert and fletchings would weigh about 315 grains. Add a 100-grain point and you get a 415-grain arrow. Shoot that arrow from a 70-pound bow drawn to 29 inches, and a speed of about 290 feet-per-second is likely.

The KE value for that arrow is 77 foot pounds. That’s well above Easton’s recommendation for any of those animals. So it’s safe to say that arrow is sufficient for bowhunting all of them.

The F.O.C. for that arrow is 12 percent, which is also within Easton’s recommended range. If I add a bunch of weight to the front of that arrow to try to get to 20 percent F.O.C., I am increasing the penetration capability of an arrow that already is capable to killing a deer, elk or black bear.

That’s not necessarily a bad thing. But remember to consider arrow spine and performance, along with your hunting expectations as you are building arrows with an eye toward boosting F.O.C.

A simple, inexpensive way to test arrow performance with different F.O.C. values is to get screw-in field points of varying weights. Saunders makes field points as heavy as 250 grains. Shoot several arrows with points of different weights at whatever you consider to be your maximum effective range. By doing this, you should be able to determine what gives you the tightest, most consistent groups.

Saunders 250-grain field point

Don’t just look for the tightest groups. You also want to consider forgiveness. That is, which arrows hit closest to your aiming point when you make a bad shot. If you have an arrow setup that produces 2-inch groups at 50 yards, but a slight bobble on your part throws the arrow off 8 inches, versus an arrow setup that produces 4-inch groups, with imperfect shots only missing by 3 inches, you should consider going with the latter setup.

Know Your Archery Glues

Stick it, for the win!

Archery is a game that requires lots of glue.

We glue points, inserts and nock bushings inside arrow shafts. We glue vanes, feathers and certain nocks onto arrow shafts.

Sometimes you want bonds to be permanent. Sometimes, you want to be able to separate parts later.

To get the right parts to stick the right way, you’ve got to know your archery glues.

CYANOACRYLATES

This is a family of fast-setting gels and liquid glues commonly used for fletchings, point inserts and sometimes nock bushings and nocks.

You’d use a cyanoacrylate for anything you want to stick permanently and quickly. Let’s say you’re putting a point insert into a hunting arrow to receive screw-in field points and broadheads. You’d use a cyanoacrylate because these inserts typically are intended to be permanent.

Attaching fletchings to arrows is a common use for cyanoacrylates because the glue enables the fletchings to stick where you put them very quickly. Pay attention to the type of cyanoacrylate you choose for fletching. Not all work equally well on both plastic vanes and feathers. Likewise, if you’re working with wood arrows, some of these glues work better on wood than others.

HOT MELTS

These glues come in stick form. You apply a flame to the glue to melt it into whatever you want to stick to another surface.

Hot melts are great for products you might remove, such as points and nock bushings. Should the time come, you can heat the point or bushing, which will loosen the glue, and that component can then be easily removed.

Understand, however, that you should never subject carbon to high heat, like an open flame. That will cause the carbon to crack.

Another method for softening hot melt that’s already holding components in place is to use hot water. Let’s say you want to remove a point that’s glued in place inside a carbon arrow. Submerge the arrow end into a pot of hot water for a few seconds, and the glue will soften so you can remove the point with a pair of pliers. (Don’t use your hands or you’ll burn them.)

This is a safe way to remove components from carbon arrows without damaging the carbon.

COLD MELT

Cold melt glues also come in stick form, and are applied by heating them. They require less heat than hot melts to liquify the glue, however.

Cold melts are great for gluing components where you don’t want to use high heat – such as anything being inserted into a carbon arrow shaft. The lower melting temperature required to liquify these glues minimizes the risk of damaging carbon.

They’re great for nock bushings, since these bushings sit so close to arrow shafts. So let’s say you want to remove a bushing. You’ll have to heat it to liquify the glue holding it in place. Since the bushing is so close to the shaft, if it were held in place with hot melt, the amount of heat required to loosen the glue might be enough to damage the carbon, where the lesser amount of heat required to loosen a cold melt would be safer.

EPOXY

Epoxies used for archery purposes usually require a mix of two liquids at the time the glue is applied. Epoxies don’t set up fast, so you have time to work with your products to get them in position, before they stick. Once an epoxy cures, it usually forms one of the hardest bonds you’ll find. Epoxies are great for hidden inserts that can take some time to position correctly inside arrow shafts, and for bow grips.

Mathews VXR Series 2020 Compound Bows Review

Mathews Archery launched the VXR Series bows as its flagship hunting line for 2020.

Watch here as Lancaster Archery Supply’s P.J. Reilly runs through the features and technologies built into these bows, which are the VXR 28 and the VXR 31.

Mathews took a lot of the technology built into its 2019 Vertix line, such as the Switchweight Mods, and put it into the VXR line. The Switchweight Mods allow an archer to change the weight range of a particular bow simply by changing mods. Previously, changing the weight range required changing limbs.

The VXR 28 is sure to be a hit with bowhunters, while the VXR 31 will be a great choice for bowhunters or 3D archers as well.

2020 Bowtech Revolt Series Compound Bows Review

New for 2020, Bowtech introduced its Revolt Series of compound bows. The series includes the Revolt X and the Revolt.

Watch here as Lancaster Archery Supply’s P.J. Reilly reviews the features and technologies built into the 30-inch Revolt and the 33-inch Revolt X.

No question, the most significant feature of these bows is the Deadlock Cam system. This is a feature Bowtech introduced early in 2020 in the Reckoning target bows. It allows the archer to use an Allen key to move the cam left or right while tuning to get perfect arrow alignment.

The Revolt bows mark the first hunting bows by Bowtech to include this new technology.

Hoyt 2020 Alpha Series RX-4 and Axius Compound Bows Review

For 2020, Hoyt has introduced the Alpha Series compound bows, which include the carbon RX-4 and aluminum Axius models.

Watch here as Lancaster Archery Supply TechXpert P.J. Reilly runs through the features and technologies built into these 29.5-inch-long bows.

These are the shortest bows Hoyt has ever offered in their premium line. They are designed with the hardcore hunter in mind, who will use them in ground blinds, tree stands and in the deep backcountry.

Light and maneuverable are the calling cards of these bows.

2020 Prime Archery Black Series Compound Bows Review

For 2020, Prime Archery has introduced its Black Series of compound bows, which has offerings for both bowhunters and target archers.

Watch here, as Lancaster Archery Supply TechXpert Dustin Cimato runs through the features and technologies offered in this series of bows, which includes models that measure 31 inches, 33 inches and 35 inches long.

Arguably the most noted feature of these bows is the rotating module for adjusting draw length. Previously, Prime bows were cam specific, which meant that to change draw lengths, the cam had to be changed.

With the Black Series bows, changing draw length is as simple as rotating a module.

 

2020 Elite Kure Compound Bow Review

Elite Archery introduced the all-new Kure compound bow as its flagship hunting bow for 2020.

Lancaster Archery Supply’s P.J. Reilly talked to Elite engineer Josh Sidebottom and Elite pro archer Nathan Brooks about the technologies built into this new bow.

An all-new cam powers this bow, with beefier axles and a different configuration – both of which help to eliminate cam lean and provide for more stability at the end of the limb tips.

But the real advancement Elite brought to this bow is S.E.T. Technology. Brooks explains this system allows an archer to adjust the limb pocket while tuning, without needing a bow press.

2019 Prime Logic CT3

Prime Archery unveiled the Logic CT3 as one of its flagship hunting compound bows for 2019. In the video, LAS TechXpert P.J. Reilly runs through the features of the CT3.

The CT3 measures 33 inches long, with a 6.25-inch brace height and IBO speed rating of 335 feet per second. It features Prime parallel cam system and the “centergy” technology, which puts the top of the grip in the physical center of the bow. By doing this, the bow balances better and has perfectly level nock travel.

The riser features the Prime “swerve,” which features a bend in the lower part of the riser to match the bend in the upper part. These matching bends allow the riser to flex in a uniform fashion during a shot, which minimizes vibration.

2019 Obsession FX6, FX7, FXL and Lawless Compound Bows

Obsession Bows has unveiled the FX6, FX7, FXL and Lawless compound bows as flagships in its lineup of offerings for 2019. In this video, LAS TechXpert P.J. Reilly runs through the features of these four Obsession bows.

All of the bows features Obsession’s new OB Traxx cam, which offers improved speed and drawing comfort and a letoff of 90%.

The FX6 is 32.75 inches long, with a 6-inch brace height and IBO speed rating of 360 feet per second.

The FX7 is 32.75 inches long, with a 7-inch brace height and IBO speed rating of 350 feet per second.

The FXL is 34 inches long, with a 6.5-inch brace height and IBO speed rating of 350 feet per second.

The Lawless is 32.75 inches long, with a 5.125-inch brace height and IBO speed rating of 370 feet per second.

 

2019 Hoyt RX-3, Helix and ProForce FX Compound Bows

Hoyt introduced its 2019 lineup of compound bows, which include the RX-3, Helix and ProForce FX bows. In this video, Hoyt sales representative Gus Edwards describes the three bows to LAS TechXpert P.J. Reilly.

The RX-3 is Hoyt’s flagship carbon hunting bow. The RX-3 measures 30.5 inches, with a 6-inch brace height and IBO speed rating of 342 feet per second. The RX-3 Ultra measures 34 inches long, with a 6.75-inch brace height and IBO speed rating of 334 feet per second. The RX-3 Turbo is 31 inches long, with a 6-inch brace height and IBO speed rating of 350 feet per second.

Hoyt redesigned the carbon riser of the RX series to be wider, which helps kill hand shock. All RX bows also feature an adjustable grip that can be moved laterally to help in tuning the bow.

The Helix is an aluminum bow that measures 30.5 inches long, with a 6-inch brace height and IBO speed rating of 342 feet per second. It also comes in an Ultra version which is 34 inches long, with a 6.75-inch brace height and IBO speed rating of 334 feet per second.

The ProForce FX is a mainly target bow Hoyt introduced for 2019, featuring Hoyt’s signature shoot-through riser. It measures 32.75 inches long, with a 6-inch brace height and IBO speed rating of 332 feet per second.