Ints, each a little larger than the former, are 
afterwards successively passed through the 
barrel in the same way, until the bore has ac- 
quired the magnitude intende I. By this op< - 
ration the barrel is very much heated, espe- 
cially the first time the borer is passed through 
•it, by which means it is apt to warp. To 
prevent this in some measure, the barrel is 
covered with a cloth kept constantly wetted, 
which not only preserves the barrel from an 
excess of heat, but likewise preserves the 
temper of the bit from being destroyed. The 
borer itself must also be withdrawn from time 
to time ; both to clean it Irani the shavings 
of the metal and to oil it, or repair any da- 
mages it may have sustained. Every time a 
fresh bit has been passed through the barrel, 
the latter must be carefully examined, to see 
if it has warped ; and likewise if there are any 
spots, by the workmen called blacks, on its 
inside. When warped, it must be straight- 
ened on the anvil, for which a few slight 
strokes on the convex parts will be suffi- 
cient ; and this is termed setting-up the bar- 
rel. When black spots are perceived, the 
corresponding part on the outside must be 
marked, and driven in by gentle strokes with 
'the hammer, when they will be completely 
removed by passing the borer another time 
through the piece. 
The equality of the bore is of the utmost 
consequence to the perfection of a barrel ; in- 
somuch that the greatest possible accuracy in 
every other respect will not make amends for 
any deficiency in this. The method used by 
gunsmiths to ascertain this is by a cylindrical 
plug of tempered steel highly polished, about 
an inch in length, and fitting the bore ex- 
actly. This is screwed upon the end of an 
iron-rod, and introduced into the cavity of the 
barrel, where it is moved backwards and for- 
wards ; and the places where it passes with 
difficulty being marked, the boring bit is re- 
peatedly passed until \i moves with equal 
■ease through every part. Any person who 
washes to know the merit of his piece in this 
respect, may do it with tolerable accuracy bv 
means of a plug of lead cast on a rod of iron ; 
or even by a musket-ball filed exactly to the 
bore, and pushed through the barrel by a 
ramrod ; taking care, however, not to use 
much force lest the ball lie flattened, and its 
passage thus rendered difficult. 
The lirst tool employed in forming the 
breech-screw is a plug of tempered steel, 
somewhat conical, with the threads of a male 
screw upon its surface, and by the workmen 
-termed a screw -tap. This being introduced 
into the barrel, and worked from left to right 
and back again, until it has marked out the 
■first four threads of the screw, another less 
•conical tap is introduced; and when this lias 
carried tiie impression of the screw as far as 
it is intended to go, a third one, nearly cy- 
lindrical, is made use of, scarcely differing 
from the plug of the breech intended to fill 
the screw thus formed in the barrel. The 
plug itself has its screw formed by means of 
a screw-plate of tempered steel, with several 
female screws, corresponding with the taps 
employed foi forming that in the barrel. 
Seven or eight threads are a sufficient length 
for a plug : they ought to be neat and sharp, 
so as completely to fill the turns made in the 
barrel by the tap. The breech-plug is then 
to be case-hardened, or to have its surface 
converted into steel, by covering it with shav* 
Vox. I. 
GtJN-SMITHERY. 
mgs of horn, or the parings of the hoofs of 
horses, and keeping it for some time red-hot; 
after which it is plunged in cold water. 
Thus the common barrels, for the purposes 
especially of sporting, are made ; but there 
are some other methods of manufacture, by 
which the barrels are made to differ in some 
respects from those just described, and are 
thought to be considerably improved. One 
kind of these are called twisted barrels ; and 
by the English workmen are formed out of 
the plates made of stubs, as above described. 
Four of these, of the size already mentioned, 
are requisite to make one barrel. One of 
them, heated red-hot for five or six inches, 
is turned like a corkscrew, by means of the 
hammer and anvil ; the remaining parts being 
treated successively in the same manner un- 
til the whole is turned into a spiral, forming 
a tube, the diameter of which corresponds 
with the bore of the intended barrel. Four 
are generally sufficient to form a barrel of the 
ordinary length, i. e. from 32 to 38 inches ; 
and the two which form the breech or 
strongest part, called the reinforced, part, 
are considerably thicker than those which 
form the muzzle, or fore part of the barre. 
One of these tubes is then welded to a part of 
an old barrel to serve as an handle ; after 
which the turns of the spiral are united by 
heating the tube two or three inches at a 
time to a bright white heat, and striking the 
end of it several times against the anvil in a 
horiz ontal direction with co nsiderable strength, 
which is called jumping the barrel ; and the 
heats given for this purpose are called jump- 
ing heats. The next step is to introduce a 
mandril into the cavity, and to hammer the 
heated portion lightly, in order to flatten the 
ridges or burrs raised by the jumping at the 
place where the spirals are joined. As soon 
as one piece is jumped throughout its whole 
length, another is welded to it, and treated in 
the same manner, until the four pieces are 
united, when the part of the old barrel is cut 
off, as being no longer of any use. The 
welding is repeated three times at least, and 
is performed exactly in the same manner as 
directed for plain barrels ; and the piece may 
afterwards be finished according to the direc- 
tions already given. 
1 he advantages of twisted barrels are, after 
all, somewhat problematical ; where there is 
so much of welding, and that in a spiral 
form, the welding is more likely to be done 
in a careless manner, or with some imperfec- 
tion in some part, than when it is a plain and 
obvious business : nor have we observed that 
twisted barrels are less liable to burst than 
plain ones, where the latter have been well 
and carefully forged. 
The Spanish barrels have been long held in 
great estimation ; yet as the Spanish iron is 
universally allowed to be unusually good, it 
is probable that the superiority of their bar- 
rels is owing more to the goodness of the ma- 
terials than to the skill of the workmen. It 
must be observed, however, that instead of 
making the plates overlap a little in the place 
where they join, they give one of them a 
complete turn ; so that every Spanish barrel 
may be said to be double throughout its 
whole length. The different portions of the 
iron are aiso forged in such a manner, that 
the grain of the iron is disposed in a spiral 
manner; whence it has the same effect with 
a ribbon or twisted barrel. The outside is 
5 U 
8 
finished by turning them in a lathe ; whence 
probably they are always less elegantly 
wrought than the French and English pieces. 
The great value put upon them is also 
thought to be more owing to fancy than to 
any real good qualities the}' possess. For- 
merly they were made from three to three feet 
and a half long ; their bore being such as to 
admit a bullet from 22 to 24 in the pound, 
and their weight from three to three pounds 
and a half. The reinforced part extends two* 
fifths of the length ; and at 10 or 12 inches 
from the breech is placed a sight, such as is 
usually put upon rifle-barrels, or those in- 
tended only for ball. According to Espinas, 
arquebuss-bearer to Philip IV. the weight of 
a Spanish barrel ought to be four pounds and 
a half when the length is 42 inches ; but both 
in weight and length they are now much 
reduced, and seldom exceed the dimensions 
already mentioned. 
The principal imperfections to which gun - 
barrels are liable, are the chink, crack, and 
flaw. The first is a small rent in the direc- 
tion of the length of the barrel ; the second 
across it ; and the third is a kind of scale or 
small plate adhering to the barrel by a nar- 
row base, from which it spreads out like the 
head of a nail from its shank, and, when se- 
parated, leaves a pit or hollow in the metal. 
I he chink or flaw are of much worse conse- 
quence than the crack in fire-arms, the force 
of the powder being exerted more upon the 
circumference than the length of the barrel, 
i’lie flaw is much more frequent than the 
chink, the latter scarcely ever occurring but 
in plain barrels formed out of a single plate of 
iron, and then only when the metal is defi- 
cient in quality. When flaws happen on the 
outside they are of no great consequence ; 
but in the inside they are apt to lodge mois- 
ture and foulness which corrode the iron, and 
thus the cavity enlarges continually till the 
piece bursts. This accident, however, may 
arise from many other causes besides the de- 
lect of the barrel itself. The best pieces will 
burst when the ball is not sufficiently rammed 
home, so that a space is left between it and 
the powder. A very small windage or pas- 
sage for the inflamed powder between the 
sides ot the barrel and ball will be sufficient 
to prevent the accident ; but if the ball has 
been forcibly driven down with an iron ram- 
rod, so as to fill up the cavity of the barrel 
very exactly, the piece will almost certainly 
burst, if only a very small space is left be- 
tween it and the powder ; and the greater the 
space is, the more certainly does the event 
take place. A piece wilf frequently burst 
from having its mouth stopped up with earth 
or snow; which accident sometimes happens 
to sportsmen in leaping a ditch, in which they 
have assisted themselves with their fowling- 
piece, putting the mouth of it to the ground; 
and when this did not happen, it is only to be 
accounted for from the stoppage being ex- 
tremely slight. For the same reason a 
musket will certainly burst if it is fired with 
the muzzle immersed only a very little way 
in water. It will also burst from an over- 
charge ; but when such an accident happens 
in other circumstances, it is most probably to 
be attributed to a defect in the workmanship, 
or in the iron itself. These defects are prin- 
cipally an imperfection in the welding, a deep 
flaw having taken place, or an inequality in 
the bore ; which last is the most common of 
