Mike Yardley continues his quest for the perfect gunfit as he explores the importance of drop
We considered length and pitch in some detail last month. I noted that I like to see one to two fingers widths between the tip of the nose and the base of the thumb when the gun is normally and properly mounted in the horizontal plane. This usually equates to an angle of about 90 degrees between upper and lower arm. An overhead target may also be used to confirm that there is not too much length, though my general rule is to keep the stock as long as possible without impeding the swing.
Okay, enough on length, save perhaps to note that I think many stocks can benefit from a traditional bump at heel to provide a little more control and to help keep the muzzle down in recoil. Length is without doubt an important gunfit variable, but, in my book, drop – the extent to which the stock is bent down relative to the rib axis – is the most important variable of all. It is much more difficult to compensate for this consistently, whereas just moving one’s front hand to rear or front of the forend may help with not-too-gross length problems. Drop determines the elevation of the gun in the vertical plane in a very similar manner to the rear sight of a rifle – indeed the rear sight of a shotgun may simply be considered the relationship between your properly placed head and the wood or plastic of the comb.
Too high a stock – which will cause you to see excessive rib – will usually make you shoot high; too low a comb can cause low shooting, but it may also make the eye opposite the rib take over in some circumstances, because the view to the eye that should be looking down the rib is blocked. For this reason, I like to check drop both in the horizontal plane and with the gun pointing at about 45 degrees up. If the client can lose the bead in some circumstances the comb is probably too low.
Too low a comb may also cause intermittent high shooting because those who have a stock that is too low may be tempted to lift it to see the target. Indeed, head lifting is a common fault even in those who have perfectly fitted guns, but good gunfit can make it less likely. Gunfitters should also be aware that many shooters compensate for poor drop dimensions by subtly raising their head or pressing it down excessively. Be on the look out for this, and, if necessary, apply a little pressure to the client’s head to make sure they are not cheating! Normal cheek pressure must be maintained to assess drop correctly. A well-designed stock will allow for consistent cheek pressure to be applied effortlessly.
How do you measure drop?
Usually with a specialist tool called a ‘bend stick’; although the combination of a metre rule and a smaller one would do the job as would any straight edge and small rule or tape-measure. It should go without saying that safety is paramount: always check a gun is unloaded and unobstructed, and if possible, apply the safety when gunfitting. Drop is normally measured at the comb (the front/nose of the comb) and at the heel (the rear of the comb). Sometimes a central “drop at face” measurement is taken by London makers. I measure drop within 1/16”.
Drop at any given point is the distance between the top surface of comb and the axis of the rib as it extends backwards into space. Typical drop dimensions for a modern clay shooting over-and-under intended for Sporting use would be 13/8” at the front of the comb and 21/8” to the rear, although older guns may be a little lower at heel – many Brownings, for example, have a shelf dimension of 2¼” at heel. Classic side-by-side measurements are 1½” and 2”.
Trap guns may have higher combs of course (and so less drop) especially if they are intended for international disciplines – 1½” is not uncommon. They may also have parallel, semi-parallel, or Monte-Carlo combs – a form of butt that has a step to the rear and increases stock depth allowing for a more upright shooting style if required. Montes – that originate from live pigeon shooting guns used in Monte-Carlo – are also useful for those with long necks and/or sloping shoulders. A Monte-Carlo comb does not need to be excessively high either – though some are.
There is much argument about fitting for drop – and much room for individual variation and preference as well. My intention here is to keep it as simple as possible. When I fit an over-and-under for clay shooting, I am usually looking for the following pictures as starting points:
You will note the differences for Sporting, DTL and international trap. Now, don’t write and tell me your gun is set up differently! Many guns are set up differently: this is exactly as stated – a starting point for experiment. For Sporting, I like to see the pupil sitting on the breech, for DTL, a little higher. For international Trap the bulk of the iris, the coloured part of the eye, should appear to be sitting on the breech when the shooter’s head is in a normal position on the stock.
I often enjoy using side-by-sides in clay competition. It has been my experience, all other things being equal, that side-by-sides tend to shoot a little lower than over-and-unders, I believe that it may be due to flexing of the grip or thinner action table. A high fit can be useful in a gun intended for driven targets because it helps to keep up on the line of birds and also equates to a little more lead. A high fit in over-and-under or side-by-side may suit those who need to close an eye, although a high rib is another means of improving field of view.
Drop not only locates the position of the eye over the breech, it also affects the positioning of the butt sole at the shoulder. Generally speaking (and there are exceptions), the top line of the stock of the mounted gun should be in line with the top of the shoulder – exceptions occur as some people like to mount the gun stock lower. One certainly does not want to see any of the butt sole above the shoulder.
Some people – notably those with long necks, sloping shoulders or small heads – may be well served with a Monte-Carlo stock as discussed. This can be useful for young shots and women as well: anyone with a head smaller than the average male is likely to need a higher stock than the norm to get their eye properly in line with the rib. I am a particular fan of Monte-Carlo stocks because they usually keep the top of the comb parallel or nearly so with the rib axis. If the comb is acutely angled, felt recoil will be increased as it accelerates into the cheekbone. If it is parallel or nearly parallel, and well profiled, it will glide back smoothly. There will also be less rotational effect in the vertical plane – this is especially important in a Trap gun.
Once you have adjusted drop – and temporary additions to comb height may easily be made with rubber comb raisers or strips of card and vinyl electrician’s tape, which is kinder to stocks than other types, but no guarantees given. For domestic Skeet, what you will want to see at the pattern plate will be a pattern distribution something like 50:50, 45:55 or 60:40. That is 50 per cent above the mark and 50 per cent below. My preference for all-round shooting, as noted in an earlier article, is 60:40 and this is the best starting point for Sporting in my experience too. DTL may be shot with a 60:40 distribution, though some prefer a high comb, 70:30, 80:20 or even, 90:10.
I do not normally favour extremes, but have found in my own guns that I usually prefer a slightly higher comb for DTL than Sporting and a significantly higher one for ABT or Olympic Trap. You will have to experiment to find your own personal preference. Remember, if you lengthen a stock you will reduce comb height on a conventional stock, if you shorten it, you effectively increase comb height; and thick stocks are effectively higher than thin ones.