The Modern Crossbow

by Terry Stewart

  This may be built up by glueing two half inch thick lengths of hardwood to each side of the stock at the fore-end. By rounding off after gluing, a 'Beavertail' fore-end will be obtained. You may prefer a deep swelled fore-end designed to keep your fingers below barrel level to prevent them being hit by the bowstring -- incidentally, a most painful experience.

  Some crossbows have pistol type forehand grips, similar in style and position to those seen on tommy guns, and related weapons that were intended to be shot from the hip. This type of grip is best left on these weapons and should never be used on a crossbow, unless it is positioned just forward of the trigger a few inches to enable the crossbow to be shot using the hip rest technique described later in this book. The ones I have in mind have the grip too far forward for hip rest shooting and should at once be discarded as quite useless. In all good shooting the left, or supporting, elbow should be as well under the stock as is comfortable, and certainly not out to the side. This is impossible to accomplish with a pistol hand foregrip, as the actual method of holding makes the elbow push up and out to the left which is entirely wrong, resulting in an unsteady and weak position.

  If using the hip rest shooting position, the fore-end grip in this case will not actually be at the fore-end of the stock as we know it but in fact only a few inches in front of the trigger. However, as we are dealing here with the types of forehand grips on crossbows, and this is gripped by the left or forward hand, it is essential to mention this type of grip for those who may prefer it, and for target shooting it is a favourite of mine, though on a hunting crossbow my preference is for the orthodox forehand grip. The hip rest forehand grip must be in a suitable position forward of the trigger to fit the left elbow firmly and comfortably into the correct position for hip rest shooting, by either gripping or cradling it in the palm of the left hand.

  A pistol grip designed for hip rest shooting would be suitable if placed sufficiently close to the trigger to be used in this position, or alternatively a deep stock at this position to rest on the hand. Perhaps the best idea is an adjustable rod with a ball at its base to slide up or down in the stock as required when shooting at various ranges. This ball is cradled in the palm of the left hand and, with the elbow in position on the hip, is ideal for steady shooting.

  Butts

  Crossbow butts, whether hunting or target design, must have the comb of a sufficient height to rest the cheek, or at least the jaw on, if it is to be of any use.

  As the stock is elevated to shoot at long ranges, the butt comb must be high enough to contact the check or jaw as the butt is moved down the shoulder. A steady and invariable pressure of the face, jaw or cheek, on the butt is an essential to good shooting. A butt comb height suitable for shooting at range of 30 yards will be too low for 70 or 100 yards unless the comb height were adjustable, and I do know of at least two target crossbows with adjustable combs. The difference in height would be slight in a well designed butt, and it is impossible to have a fixed butt perfect for every elevation. Due to the higher trajectory of a target crossbow employing a light draw weight and the longer ranges shot, the comb is of necessity higher than that of a hunting crossbow of flatter trajectory, and heavier draw weight that is designed to be shot at closer ranges.

  A good guide to butt comb height is to have the comb on a hunting crossbow level with the top of the barrel, or very slightly below it. As a rule target crossbows combs are higher than the barrel line to allow the cheek to be rested for the higher trajectory shots.

  The butt should not in any way be curved to fit the shoulder, it should have a slight slope to enable the butt to be moved up or down the shoulder as desired to maintain contact throughout its full length. A curved butt being moved down would mean that only the fullest part of the curve would contact the shoulder with resultant unsteadiness when shooting.

  The butt length is measured from the centre of the trigger to the toe of the butt, an average being fourteen to fourteen and a half inches, though this will of course vary according to the individual. It should, however, be able to be raised to the shooting positions without having to be pulled in too much, or pushed out. If too short, a cramped bunched-up hold will result, and if too long, a strained position will be felt.

  Do remember that the draw length of the bow added to the length of the butt from latch to butt plate must be of a length to enable you to comfortably reach forward to the string when the butt is against your abdomen prior to drawing back the string.

  For instance, if you had a long target bow drawing twenty inches, with a butt length of fourteen inches, giving in all a total distance of thirty-four inches from butt plate to where the bow is fitted into the stock. A small man, lady, or youth may experience difficulty in comfortably reaching for the string; therefore this factor should be taken into consideration when constructing a crossbow, although it is only likely to arise with a target crossbow employing a long bow.

  Hand

  The rear or right-hand grip on a crossbow is known as the hand. The best hand grip is of the pistol type in which the portion gripped by the fingers is nearly vertical. This enables the trigger to be squeezed and controlled in the most natural position, the elbow of the right arm is also held in the best position for steady shooting with this type of grip. The full pistol hand is mainly seen on target crossbows, with a half- or semi-pistol grip on hunting crossbows. Whatever type of hand is used it must be comfortable, and as far as possible fashioned to provide an unvariable hold. An increasingly popular hand grip on crossbows is the thumbhole type. This hand grip is incorporated as a part of the butt itself, the thumb being placed through a shaped hole allowing three fingers around the grip, the index finger on the trigger.

  Sights

  Rear sights on crossbows are of two main types, peep sights and vee sights. The peep type is best used for target shooting and the vee sight for hunting, as this sight gives a clear view of the animal rather than one spot on its body. A low, wide vee is preferable to a high, narrow one for the same reason. All rear sights must have some method of elevation, and in the case of a hunting crossbow it is best to have this adjustment easily and swiftly made. I believe in having a maximum of three different elevations for hunting purposes in units of one quarter of an inch. This simplifies rapid choice of elevation under hunting conditions, with the 1/4" adjustments showing an appreciable increase in range.

  I have used with success an immensely simple, though effective, hunting sight requiring no manual elevation; yet with an instantaneous selection of two ranges, 30 yards and 50 yards. This sight consists of a fixed double aperture rear sight with a peep hole set 1/8" above the level of the foresight bead, for sighting at up to 30 yards; above this peephole is a 'V' notch sight for sighting at 50 yards. To change elevation instantaneously from one range to the other, without having to look away from the quarry, (an invaluable asset), one simply transfers the eye from the peep sight to the vee sight, or vice versa as required.

  The stark simplicity of a fixed double aperture sight requires a certain amount of estimation of the distances between 30 and 50 yards in placing the foresight bead in such a position on the quarry so as to compensate for the lack of a particular sighting elevation.

  For example, if you estimated a deer to be at 40 yards, you would sight through the bottom peep hole placing the beadsight on the heart and lungs area, but you are at 40 yards, so raise your bead up until it is sighting half way up the body. This should compensate sufficiently to place the bolt in the heart and lungs area.

  As an alternative, it would be possible to use the 'V' notch sight and compensate by aiming lower on the quarry. Two snags occur doing this; first of all if aiming lower on the vital area of a deer one has invariably no sight whatsoever on the body, the bead coming under the body. It is better to retain a point of aim on the quarry itself, even if high up, than be aiming at a patch of earth somewhere below it. The other point is that you are liable to become confused if you vary your technique. sometimes using peep sight at 4
0 yards and aiming higher, or sometimes using the notch sight and aiming lower. The simpler you are able to keep your technique the better. Keep to two fixed sights only. Do not attempt this method using three or even four rear apertures in an attempt to have a sight for three or four distances, as under hunting conditions you may select the wrong one.

  A hunting crossbow with fibreglas bow.

  A Target crossbow with composite bow.

  Stringing the crossbow. (The author's method.)

  Target crossbows should also have a lateral adjustment to allow for windage; this is usually in the form of a sliding bead on the foresight bar, but is sometimes seen as a lateral adjustment on the rear sights. The unit of vertical adjustment on target crossbow rear sights is in units of one-eighths of an inch, as this finer increase is required for extremely precise shooting.

  Hunting crossbows have the rear sight only adjustable and this for elevation only as no windage adjustment is either necessary or desirable, though some lateral adjustment on the foresight is advisable for 'zeroing' purposes. Some hunting crossbows are constructed without sights, the crossbowman simply aims along the bolt at his quarry. This method has no advantage over the crossbow with sights as it reduces shots at the longer ranges to mere guesswork.

  A crossbow without sights may be considered by some as more sporting, but is it sporting to risk maiming an animal due to having no definite idea as to which spot your bolt will strike?

  The rear sight should be placed sufficiently far forward from the eye to be looked through naturally when aimed with the sight at its lowest elevation. Any tendency to pull the head back to focus results in a cramped position of the head and neck; if the head has to be pushed forward this will cause a tense, strained hold that will adversely affect your shooting.

  If you have a crossbow in your possession try this experiment to ascertain if your rear sight is correctly positioned. Take up your crossbow with the rear sight set at lowest elevation and assume your usual position to shoot with both eyes closed. Place your cheek along the butt until you are perfectly comfortable and in the position you feel is correct. Now open your right eye to look through the rear sight. Surprised? Were you completely out of focus and had to move your head back or forward along the butt to take proper aim? If so, the remedy is to adjust your sight either closer to or farther away from your eye as much as will enable you to conduct the sighting experiment without having to move your head. The use of a six-hole aperture peep sight on a target crossbow will enable you to select the aperture best suited to the prevalent light conditions on any particular day and to adjust the aperture size to suit changing light conditions.

  A popular sighting arrangement on American target crossbows is the offset type. The front sight bead is offset 1/4" to the side of the bolt slot centre with the rear aperture sight offset in line with it. This method requires the lateral windage adjustment to be on the rear sight as the front sight bead is an immovable fixture.

  With this particular sighting arrangement it is not necessary to elevate the stock as much at the longer ranges as would be necessary if the foresight were on a bridge of the usual type an inch or so above the stock, and the offset of 1/4" is so slight that its effect on accuracy may be disregarded as it in no way has any adverse effect. The same effect is obtained by a stock with the extreme fore-end dropped below barrel level with sights 1/4" below the flight of the bolt. This also will not require as high a butt comb and is ideal for a target crossbow, but is not suitable on a hunting model as no point blank sight may be taken due to the foresight being below barrel level and the rear sight above the barrel.

  The hunting crossbow's fore sight and rear sight when in position on the stock must be mounted exactly in line with each other and at exactly the same height from the barrel. An alternative method is to place the hunting rear sight at its lowest elevation from one-sixteenth to a maximum of one-eighth of an inch higher than the fore sight. This gives a slightly rising flight to the bolt up to about thirty yards.

  Do not be tempted to raise the rear sight more than one-eighth of an inch above the fore sight or you will find that from point blank range to about twenty yards your bolts will strike anything from one inch to twelve inches above the spot you aimed at.

  Whether you use this principle, or prefer both rear sight and fore sight at exactly the same height, do not on any account place the rear sight even a fraction lower than the fore sight as this will cause your bolts to have a slightly downward flight, striking at the short distances inches below your point of aim, and at the longer distances your bolts will 'nosedive' even yards in front of the point of aim.

  The rear sight may be on a slightly higher elevation than the fore sight, or exactly on a level with it, but never at any time even a fraction of an inch below it.

  Release Latches and Triggers

  The action of the latch upon release is to drop below barrel level into the latch recess and so release the string along the barrel to drive the bolt from the stock.

  When experimenting with various release latches and triggers made from widely varied materials: fibre alloy, brass, wood with metal insets, steel, etc., it became obvious that the only safe release mechanism material is case hardened steel; or at least steel with the contact points of trigger and latch case hardened. The use of other softer materials only leads to undue wear on the release mechanism which may become dangerous.

  As the metal wears in non-steel mechanisms at the contact points this gradually alters trigger pull off until your bow may discharge at the slightest touch. If constructing your own crossbow, a steel latch and trigger does call for a lot of hard work with hacksaw and file working to fine limits; any error calls for the lot to be scrapped and once again the tedious job of hand shaping steel. This I feel is the reason so many amateur enthusiasts use softer materials, they are simply easier to work with, but they are not the best. A case hardened steel latch and trigger will stand up well to many months of regular shooting with perfect safety.

  The surfaces of the trigger and latch in contact with each other should be as short as safety will allow and in perfect contact with each other throughout their entire width, with the general latch workmanship of a first class nature.

  A safe positive lock when in the cocked position is essential; a cocked and loaded crossbow that may suddenly slip off contact and shoot its bolt is a most dangerous weapon.

  While experimenting with various release mechanisms this has on occasion happened to me, and though no damage to property or injury to anyone was caused, it is a most unnerving experience and will cause apprehension whenever your crossbow is cocked. It is essential to have every confidence in the holding ability of the latch mechanism. The latch should cock easily and be safe to the point of holding even under moderate shock, such as being dropped.

  The trigger action must be smooth and effortless no matter what draw weight your bow is, and the latch must have a rapid drop with no tendency to return to the cocked position after shooting. Triggers with first and second pressures are an asset, particularly on a target crossbow. Irrespective of action the latch should be slotted to allow the rear end of the bolt through to contact the bowstring prior to release. The width necessary will ensure a correct string angle around the latch forks for an accurate release. I have seen some string release latches as narrow as 1/4" and of course, due to the narrowness, unslotted, the bolt being placed directly in front of the latch. Apart from the fact that the bowstring wears out very quickly on this narrow type of latch due to the pinched angle of the string around it, accuracy is certain to be reduced due to the bolt not being in contact with the string prior to release, it receiving a fast hit from the string rather than the fast smooth 'push' it would receive on a slotted latch.

  The inner faces of the release latch forks where the string is held must be as smooth as glass to prevent wear on the bowstring. Most latches inner faces are slightly curved to take the string in the cocked position, as on a completely vertical latch fork there may
be the tendency for the string to slide up and off, causing a premature release. I must confess that I prefer a vertical latch fork with the latch cover designed to prevent the string slipping off, though this is purely a personal preference.

  The trigger pull must be consistent and may be anything between 3 lb. to as much as 8 lb. Although a pull-off of 5 lb. is average and desirable, it is by no means essential. What is essential is that the pull off is consistently the same. Pull-off adjustments are made possible on some crossbows by means of an adjusting screw, and are most desirable on target crossbows.

  It is possible, though not ideal, to shoot well with a very heavy pull off weighing, say 8 lb., provided it consistently pulls 8 lb. at every shot. A trigger that pulls varying weights from shot to shot, due to wear at contact points or loose pivots, will never give good scores.

  The pivot pins through trigger and latch must be steel, and strong enough at the latch to take the pull of the bowstring without bending. At the same time they should be as snug a fit as possible while still working easily enough to allow smooth action. Any looseness, especially on the latch pivot, has considerable effect in variation of trigger pull.