New-York tribune., 1875-02-15
MEANS OF COAST DEFENSE.
RIPIING sMooTH-BORE CANNoN-THE RESULTS Oh
TANNED BY NEW METHOD OF TUBING.

RIPIING sMOoTH-BoRE CANNON-THE RESULTS OB-
TANNED BY NEW METHOD OF TUBING
The recommendations of the Presidents re-
cent message the subject Of rihed ordnance have
great interest among those interested coast
deienses. pamphlet embOdying q report from the
Board Of Experimental Guns has issued and it
believed by many 10 solve the problem how to convert
into Tihed cannon the smoothbore guns now in by
tie Government at various points along the coast The
Board consisting OF Col Crispin Majors Treadwe and
Baylor and Capt. Mckee OF the Ordnance Department
ordered recently, by the Secretary Of War. to
the eightinch converted rife, made from the
teniDch smooth-bore. The gun is composed Of two
paris the original tennch smooth BORE drilled to
terror diameter OF 1875 inches and lining tube OF cOled
wrought iron welded The breech OF this lining to dis
tance 326 inches double tube, the being
shrunk 10 fit closely the inner and having the
exterior diameter the inner tube at the muzzle.
screw-cosr attachment prevents the tube from being
pushed forward by the compression Of the wrought iron.
brought by repeated hrings The breech end the
tube Is closed by wrOughtiron base or cup. The te
was adjusted TO place within the bore Of the
cannon with great care, especial being used TO
bring the breech end Of the tube IN contact with the
cast iron. After the insertion Of the tube s fastened
into place by the collar at the muzze OF the piece
The rlfiing consists of Is grooves with twist OF
in 40 feet Tue weight Of the tuoe and gun, when
complete, is 1870 pounds.
Trials first made with charges OF powder varying
80 pounds and with prOjectiles varying from
pounds to note the resulting pressures and
yeociues and the effects the gum ana were prelm-
inary the Of pound charges the weight selected
for the OF the for endurance Satisfactory
suits having been attained, experiments then be-
run for testing the endurance OF the gun using pound
charges 49S rounds fred with this charge and
rounds with charge OF 80 pounds. completing q record
Of sO4 rounds S ROUNDS in all have been fred from the
gun. The yelOcties we're taken with the De BOueDg6
ebronocraph Tue ROdman pressure plug placed in the
cartndgebag was used for asceItaining the maximum
pressures The energy OF mean weight OF
jecte l737 pounds, with 55pOuBd charge SHOWS power
about equal TO the wroughtirOn Ehgsh service
rife and as II believed that the length OF the bore
would ke It possible advartaeeOusly burn little.
more powder, charge OF IS pounds was nxed as
maximum IN the tests The mean maximum pressure
with Oatterlng charges was 81 2S2 pounds, - ,
Experiments which were mace tc test the accuracy OF
The y stems OF rinlng and proectes were CONSIDERED
highly satisfactory. Tue remarkably small horizontal
devIaons afforded ndspuabe evidence Of the service
able condition and good character OF the rng and OF
the satisfactory action and accuracy OF the projectles
After nrng 6lS rounds the axmum increase OF
bore was OO4 inches. and al inches from the
bottom. BY deducting the play OF the tube
az that point. the actual maximum enlsrgement
was Oo295 inches. This found be superior 70 En-.
gsh ca periments with the best converted system I'm
OF the bore taken with guta percha show hut
inue erosion from the and this and sght gen
ers roughbess the OF are the extent OF
tbe damage the surface Of In the entire
efperiDenn and tests. The table OF comparison be-
tween sinc converted aud the English Snch nine
ION quo shows that gdnners can calculate q power
from former equal 10 that OF the latter The caou
IatoDs carried beyond 1850 yards. as at
more important barbor deieDses OF this country a
Greater ra Dge than this would generally be required
for their aseDated guns, which wonid probably DO
used case OF attack as powerful suaiiiarss TO the
.roer calibers 10neh and I2iDeh ries The calcu-
lated power against srmor plates unbackcd is at the
muEse a penetration OF $50 inches; at coo
800 Yards CTS The Board beiieve that IL some
hsrhays who're the drsDght OF water comparatively
LghL guns VI this power would have suineient energy