US 2609631 A
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Description (OCR text may contain errors)
P 9, 19.52 J. c. GARAND V 2,609,631
MEANS FOR SECURING LINERS TO FIREARM BARRELS Filed May 24, 1948 grwvwfov Jul-Ln l:- Eur-ant].
Patented Sept. 9, 1952 MEANS FOR SECURING LINERS 'ro FIREARM BARRELS John Cl Garand, Springfield, Mass. Application May 24, 1948, Serial No. 28,964
((142-715) (Granted under the act of March 3, 1883, as
amended April 30; 1928; 370 0. G. 757) The invention described the specification and claims may. be manufactured and used by or forlthe Government for governmental purposes without the payment of any royalty thereon. s
This invention relates to means for fastening a liner to a, firearm barrel for securing such liner against. displacement due to rotation of the projectile and to a method for aligning a rifled barrel liner with the rifiing of the barrel.
It is common knowledge in the firearm art that the heatof combustion of the powderin the firearm barrel is concentrated slightly ahead of the chamber. This concentration of heat plus the erosive effect of the gases rapidly erodes the bullet seat and consequently shortens the accu racylife of the barrel. Among the few successful devices employed to overcome such erosion is a liner fabricated from a highly corrosive and erosive 'resistantmaterial known as Stellite. The firearm .barrelis bored out at the breech end to accommodate such" liner and such liner extends preferably several inches beyondthe fhotspot forwardly of the chamber.
While a liner made of this materialhas more than proven its worth, considerable .troubleha-s been encounteredjin securing the liner to the barrel so that 'such; liner will remain immovably in place. The rotation of the bullet due to the rifiing in the liner sets up a torque force of considerable magnitude whicheventually unseats the liner .in the'barrel, One of the means commonly employed for securing the liner to the barrel is by threads including shrinking of the liner simultaneously with screwing the-liner into the barrel. Other means for securing the liner to the barrel includes pinning or screws, or a combination of both. Experience has shown. however, that none of the securing meansutilized so far has proven satisfactory for the reason that the torque forcestransmitted to the barrelliner are of such a high order that the securingmeans are entirely inadequate to hold the liner in place without subsequent displacement after a, somewhat limited use of the fircarm barrel.
When the liner is axially displaced by the rotation of the projectile even though such displacement be a minute amount, an opening is produced between the end of the liner and the bottom of the counterbore provided in the bar rel to accommodate the liner. It is thus possible for a portion of the propulsion gases to enter such opening and thus act to hasten the separation of the liner from the barrel proper.
This obviously is not a good condition as unpredictable forces are then acting on the barrel and forces which are not considered in the design of the barrel with the result that dangerous fractures may obtain particularly if the barrel has been weakened in machining prior to insertion of the liner. In addition to this the liner may be rapidly displaced rearwardly with extremely harmful effects.
As the barrel liner above-referred to extends a short distance beyond the throat of the cham ber, such liner must be rifled in order to properly start the bullet on its way. It should also be obvious therefore, especially to those skilled in the art that the liner must be immovably secured to the barrel, otherwise any displacement of the liner either radially or. axially will misalign the rifling in such liner with the rifling in the barrel thereby contributing to lossof accuracy of the projectile.
Accordingly it is an object of this invention to provide means for securing a barrel liner to a firearm barrel whereby the liner is secured against the torque of the bullet to immovably secure such linerto the barrel. 3 y
Another object-of this inventionis to provide a method for securing a rifled liner to a firearm barrel having corresponding rifling wherein the riflingof the liner is aligned with the barrel riiling.
V The specific nature of the invention as well as other-objects and advantages thereof will clearly appear from a -,description of a preferred embodiment as shown in the accompanying drawings in which:
"Fig; 1 illustrates a barrel liner showing the key securing means constructed in accordance with this invention in enlarged detail.
Fig. 2 is a view similar to Fig. '1 showing another arrangement of the securing means of this invention. t Fig. 3 is'a fragmentary view of a firearm barrel shown partly inlongitudinal section with a barrel liner secured in place therein by means of .this invention and also illustrating the manher of aligning the rifling in such liner with the rifling of the firearm barrel.
'Fig. lillustrates a firearm barrel showing the liner secured therein by the device of this invention.
In Fig. 1 there is shown a rifle barrel liner it embodying one form of this invention. Liner it is preferably made from a highly corrosion and erosion resistant material such as Stellite.
A plurality of longitudinally disposed keys H are is securely held in barrel l3.
with'the leadof keys I8 on the mandrel.
3 provided about the outside surface of liner I and are preferably evenly disposed thereabout.
'A preferred form ofkeys I I is a, substantially prismatic shape as shown in Fig. 1. The shape of such keys however is not limited to such form as other shapes may be employedand still lie within the scope oftthis invention. Keys I I may be of any height desired and any number of such keys may be provided about the periphery of liner I0. Still further, keys II may extend the full length of liner ID or only partway as de sired. At any rate such keys should extend a suflicient distance to insure adequate locking engagement when liner I0 is assembled into a barrel l3.
Keys II disposed longitudinally on the surface of liner I0 parallel to the axis of such liner are preferably utilized when chambering and rifling of the liner are to be done after the liner is assembled to the'barrel. Keys II are integrally formed with liner I0 and may be produced by casting or machining, A counterbore I2 is provided in firearm barrel I3 of suitable shape to accommodate liner Ill. Liner I0 is of such asize as to obtain a tight press fit. Liner I0 is forced into counterbore I'2fasby a hydraulic press. As liner I0 is forced into barrel I3, keys II provided on suc'hfliner. cut their own recesses as such liner is forced into the barrel. When liner I0 is fully seated, keys II larethen firmly embedded in the side wall'offbarrel I3. The sectional area 'of keys II is s'uclilas to adequately resist any shearing action produced by the tendency of liner ID to rotate due to the torque forces imparted to such'liner by the rotation of the projectile passing therethrough. Thus liner I0 In the fabrication of liner I0 it is sometimes more convenient to irifle and chamber such liner prior toassembly to barrel I3. .Rifiing I6 provided-ina bore I4 in liner I0 corresponds to riflin'g I9 provided in the bore of barrel I3. In this instance, keys I5 are then helically disposed on the 'peripheryofiliner having a lead corresponding to thatofrifling I6 and I9. Amandrel I1 is utilized' fo'r; aligning the rifiing I'B of liner I0 with'ri ing I9 "of barrel I3 when assemblin'gliner 1 Il to barrel I3.
"Mandrel nis' provided with keys I8 which are engageable with 'rifling I6 and I9. Liner I0 is placed over mandrel I1 and then such liner is forced into oounterbore I2 by a suitable press.
The keys I8 "on mandrel II cooperate with rifiing l6to induce such liner to revolve in accordance Thus when liner I0 isfully seated incounterbore I2,
rifiing I6 therein will [be aligned with rifling I9 in "barrel I Helicall-y disposed keys I5 will then be embedded in the wall of barrel I3, such keys cutting their own "path.
techniques required with prior art devices and which is easier and more securely fastened in the barrel. This invention also discloses a, novel method for aligning the rifling with the barrel rifling while simultaneously securing the liner to the barrel. While the preferred form of this inventionis utilized to secure a'linerto a barrel, it is desired to emphasize that the'securing means of this invention is readily applicable to any other similar situations wherein a tubular member must be secured within another member in such fashion as to overcome the torque produced by the rotational effect of a body passing through such member.
' 1. In a firearm barrel having a counterbored breech end, a liner comprising a tubular body having an external diameter of suflicient size relative to the internal diameter of the barrel counterbore to form a press-fit therebetween, and a plurality of radially disposed key members projecting outwardly from the exterior periphery of said. liner and extending longitudinally from the rear tothe front end thereoflsaidkey members being of triangular configuration'termin'at ing in an outer knife-like cutting edge embed dable inthe wall'of the barrel counterbore during the act-of forcing. said liner therein whereby said liner is immovably secured in the barrel against rotational and longitudinal displacement.
2. In a firearm barrel having a rifled bore terminating in a counterbored breech end, aliner comprising a tubular body having interior rifiing ofrthe same lead and size as the barrel rifling,
said tubular body having an [external diameter of sufficient size relative to the internal diameter of the barrel counterbore to form a pressfit therebetw.een,..and a plurality of radially dis posed key members projecting outwardly from the exterior periphery of said liner and extending helically from the .rear to the front end thereof with the same lead as the rifling in said ,.JOHN c. GARAND."
. REFERENCES CITED The following references are of record in file of this patent: I V a I r f r rrsn s'rn rss PATENTS Number v Name Date I 301,233 Hauck July 1, 1884' 1981,095 Maxim Jan.'10, 1911 1,127,26 Moilster v Feb. 2, 1915 1,355,421 3 Pedersen Oct. 12, 1920 1,544,469 Mal'aval et al June 30, 1925 2,445,777 Hah-n July 27, 1948 2, 19.9;944 Brace .et a1. Mar. 7, 1950 FOREIGN PATENTS Number Country Date provides fora liner cheaper to produce and on V