This extract from a much longer talk at Blackmore Museum, Salisbury, in 1889-90 by Pitt-Rivers describes part of his firearm series, and refers to his firearm series then part of the Pitt Rivers Museum, University of Oxford. To find the full talk see here, to find a list of items included in this series see here.

... Commencing with the branch, which as I have said was the first to engage my attention, viz, the History of the Rifle. The earliest Fire-Arms were of course Smooth-bore Cannon and Muskets. The ball was of necessity much smaller than the bore of the weapon, to allow for fouling, which was considerable, on account of the bad powder employed at that time. This caused great inaccuracy in the flight of the bullet, and the first attempts at improvement were to reduce the windage. To effect this, some of the German Fire-Arms of the 15th Century were made with grooves running straight down the bore without any spiral twist. The object of this was merely in order that the fouling might be pressed into the grooves, and the bullet was thus made to fit more closely to the "Lands" or spaces between the grooves, by this means greater accuracy was obtained. In 1820, Koster of Nuremberg began to give these grooves a spiral twist. The bullet was rammed down with a greased patch round it, which being pressed into the grooves, turned with them, and gave the bullet a spinning motion, the effect of which is of course too well understood to require explanation here. But this system was ill-adapted for Military purposes, because it took a long time to load the Rifle, and to remedy this defect, the round bullet was afterwards made with a zone or belt round the circumference. The belt fitted into two deep grooves, which ran down the bore with a spiral twist, and the bullet both in loading and firing was compelled to turn with them. Still this weapon had the same defect as the last, being difficult to load, and the attention of Inventors was directed to contriving a bullet, which would go down the barrel easily, being smaller than the bore, and which when at the bottom should be expanded into the grooves, and come out with a spiral twist. To accomplish this, Mr. Delvigne, a French officer, formed a chamber at the bottom of the barrel, which contained the powder. The bullet when rammed down, rested on the shoulder of this chamber, and by being hammered with two or three blows of the ram-rod, was expanded laterally into the grooves, just as an orange, if pressed at its opposite poles, expands its lateral circumference. But this gave the bullet the very worst form for flying through the air, being flattened by the blows of the ram-rod on the front part. The chamber was also found to get very foul, and to remedy this a pillar or stem was introduced into the breech, which answered the same purpose much better. This was called a Carbine-a-Tige, and was used in the French Army for some time. A cylindro-conoidal bullet was also introduced and the ram-rod, having a hollow out in the base of it to receive the point, obviated the defect of flattening the front part.

But it was found, that no weapon in which the ball had to be expanded by the blows of the soldier in ramming down, could be relied upon in the heat of action, and the attention of Inventors was directed to a still further improvement, by contriving a bullet which would go down the barrel easily, and which would expand itself on the discharge of the gun. A hollow was made at the base of the bullet, and it was thought that the gas in firing, would fill this cavity and press out the sides of the cylindrical part round it, into the grooves. This it did only too effectually, for it was sometimes found to press out the sides of the cylinder and blow off the head, leaving a cylinder of lead in the barrel. To meet this difficulty, a little iron cup was inserted into the hollow at the base of the bullet, and the hollow was made conoidal, smaller towards the inside, which it was thought would prevent the gas from entering the cavity, and by forcing the cup forward into the hole would press out the sides. This was called the Minie Musket, and was in use both in our own service and the French Army for a few years. But no one can see what actually takes place at the time of the discharge, and conjectures may be erroneous. It was afterwards found that the way in which the cup acted in forcing out the side[insert s, ie 'sides'] of the cylinder, was not by being forced into the cavity, but that it merely served as a sort of frame to it, to prevent its collapsing, and that the real cause of the expansion was, that the cylindrical part of the bullet, being reduced in substance and weakened by the cavity, the soft lead was squeezed into the groove merely by the pressure of the compressed air in front, and that of the gas behind. Around the cylinder, grooves had been cut on the outside of it to receive the cord which tied on the cartridge. These having been disused at one time, it was found that inaccuracy in the flight of the bullet resulted from their discontinuance, and they were re-introduced and systematised. The use of them appeared to be partly to keep the hinder part of the bullet in the rear whilst flying through the air, like the feathers of an arrow, and partly to assist in weakening the cylinder of the bullet, so as to enable it to be sqeezed [insert u ie squeezed] more easily into the grooves. Acting on this suggestion, Mr. Lancaster contrived a bullet in which there was no aperture, but in which the necessary reduction in the substance of the cylinderical [sic] part, was produced by deep grooves in imitation of the grooves formed to tie on the cartridge, which were called Cannelures. This bullet he used with a pillar breech, but as this form had become obselete [sic], Mr. Wilkinson of Pall Mall, took the matter up at this stage, and after many experiments, in which I assisted him [insert].[end insert] and [insert] He [end insert] found that a bullet, with lateral grooves of this kind when properly constructed, expanded itself merely by the opposing forces of the gas and the atmosphere. This was the desideratum that Inventors had been striving for. But in the course of these experiments, it was found by firing bullets into soft clay, so as to see the effects of the grooves of the Rifle upon them, that they received the impression of the grooves equally on the solid fore-part, which was above the lateral rings, and consequently the rings were not necessary. Mr. Wilkinson had reduced the size of his bore, and this served the purpose of reducing the resistance of the cylindrical part sufficiently to make it squeezable without the rings. Finally Mr. Pritchett took advantage of this discovery, and still further reducing his bore, produced a bullet without any rings, which he found took the impression of the grooves of the Rifle perfectly. This weapon which was known as the Enfield Rifle, continued in use in the English service for some years.

At this stage, I break off my description of the History of the Rifle: it went on improving gradually and has continued to do so until the present time, but the introduction of the breech-loading system obviated the necessity of self-expanding bullets. Opposite each figure in the diagram, I have attached a symbol. Those marked with a cross are those forms, which remained in use a long time. Those marked with a square are those which were introduced into the Service, but remained in use only a short time. Those marked with a circle, are the forms which may be said to have died out in an embryonic stage, and which, though serving as links in the development of ideas upon the subject, were never introduced into the Service, and are now very difficult or impossible to obtain, and would probably be wanting in any series of Rifles, that might be collected for a Museum, at the present time. They are the missing links, of which in pre-historic and savage Arts, such an enormous number was always exist. I have selected this series of the development of the Rifle, not because of any special interest attaching to it, but because it forms a good developmental series, and one, nearly every stage of which I was personally connected with and can vouch for, and consequently it serves my purpose of exemplifying the method to be followed in studying Savage and Pre-historic Arts in accordance with the only process that is applicable to the case, viz., that of explaining the unknown [?missing word, by] means of the known. ...

Transcribed by AP for the Rethinking Pitt-Rivers project in August 2011.