FR2751062A1 - Method of changing barrel on firearm - Google Patents

Abstract

The method involves changing the barrels on a Remington 7600 (rtm) pump action carbine. It involves drilling a bore (7) to allow the passage of a tool into it to allow the locking or release of the barrel (1). The bore can be pierced in the forestock on the pump action slide support (5). The method can involve inserting a ferrule (9) in the locking tube (4) to allow reception of a locking tool. The ferrule can be deformed into the locking tube. The ferrule can be retained by adhesive, welding or form locking.

Description

The present invention relates to a method for making easily and quickly interchangeable the various models of barrels which it is possible to mount on pump rifles, for example on those of the type of those marketed by the
Remington company under the references Remington 7600, 760 ...

 Changing the barrel currently requires complete disassembly of the front part of the rifle. The drawing in appendix 1/2 figure 1 shows the current state of the art. The barrel is dismantled by loosening the tube (4) using the holes provided for this purpose. A calibrated rod passes inside these holes and allows loosening.

This operation is delicate and tedious because the location of these holes does not allow more than half a turn to be made per movement.

In addition, during this operation, the disassembly orifices are very often deformed, which has the effect of "seizing" the clamping tube (4) in the cylinder head holder block (5) during the reassembly phase.

When the clamping tube (4) is unscrewed, disassembly of the barrel becomes possible by pulling the complete assembly (1,2,4,5,6,7,8) forward until completely clearing the breech ( 8), which is integral with the cylinder head holder block (5), its housing (3). The barrel is then released from the housing (3). It must be turned 90 "as shown in Figure 1b and pulled up to be released. Due to the current construction, this operation necessarily requires the deformation of the cylinder head bars (Sa).

This maneuver is also long and delicate and requires the skill of a gunsmith not to seriously damage certain parts of the weapon.

 The present invention therefore relates to a method for quickly and easily changing the different models of barrels adapting to a rifle of the pump type characterized in that it consists in piercing an orifice (7) allowing passage inside of it with a tool allowing the clamping or loosening of the barrel fixing means. The hole is drilled in the piece for holding the wooden front on the cylinder head bar block (5). A sleeve (9) is inserted into the tube (4) for receiving the clamping tool. The sleeve (9) is either attached to the clamping tube (4) or is integral with the tube (4) in one piece. The sleeve is inserted by gluing, welding or crimping.

 The transverse dimension of the barrel (1) is slightly less than the width between the breech bars (5a) to allow the passage of the shoulders of the barrel inside the breech bars. The shoulders of the barrel (1) are reduced by machining to allow passage thereof inside the cylinder head bars (5a).

The method according to the invention overcomes the various problems of the current design.

The disassembly of the clamping tube (4) allows quick release of the barrel (1) and only the latter without using the disassembly orifices which have the drawbacks mentioned above.

In addition, the clearance of the barrel (1) no longer causes the deformation of the breech bars (5a).

To achieve this objective, the rifle requires three very simple modifications (the drawing in Annex 2/2 in Figure 2 shows a device of the invention):
A / The drilling of the screw (7) for clamping the wood (2) on the cylinder head holder block (5) to allow the passage inside thereof of a male or equivalent key, like a flat screwdriver, cruciform
B / The addition of a steel sleeve (9) to receive the key in the tightening tube (4). This sleeve (9) can be in one piece or in several parts as indicated in the drawing and can receive the different types of keys cited in A.

It can be fixed in the tube (4) either by welding, gluing or crimping.

 C / The machining of about 3mm of the shoulders of the barrel (1) which simply allows better clearance of the latter during disassembly. This machining in no way affects either the clamping or the centering of the barrel (1) in the block (3).

These modifications (A, B, C) allow the withdrawal of the barrel (1) from the breech housing (3).

This is done after loosening the tube (4) via the sleeve (9) using a male key (bolt locked or unlocked).

The barrel (1) can then be released only with the breech in the rear position (use the latch plunger if the breech (8) is locked).

The barrel can then be pulled forward.

The cylinder head must advance to the top of the housing (3) but in no case must it come entirely out of it (space between screws and wooden front about 6 cm).

The barrel can be swiveled 90 "without touching the wood (2) or the housing screw (3) can then be removed and replaced.

The reassembly operation is carried out in the opposite direction, with however the use of the bolt pusher to authorize entry of the barrel (1) and the breech (8) into the housing (3).

 This process is likely to be implemented on rifles during their manufacture or else adapt to already existing rifles.

Claims (8)

 1 / A method for quickly and easily changing different models of barrels adapting to a rifle of the pump type characterized in that it consists in piercing an orifice (7) allowing passage inside of it d 'A tool for clamping or loosening the barrel fixing means (1).  2 / A method according to claim (1) characterized in that the orifice is drilled in the holding part of the wooden front on the cylinder head bar block (5).  3 / Method according to one of the preceding claims characterized in that it consists in inserting a sleeve (9) in the clamping tube (4) for receiving the clamping tool.  4 / A method according to claim (3) characterized in that the sleeve is attached to the clamping tube.  5 / A method according to claim (4) characterized in that the insertion of the sleeve (9) is carried out by bonding, welding or crimping.  6 / A method according to claim (3) characterized in that the sleeve (9) can be integral with the tube (4) in one piece.  7 / Method according to one of the preceding claims characterized in that the transverse dimension of the barrel (1) is slightly less than the width between the breech bars (Sa) to allow the passage of said shoulders inside said bars .  8 / A method according to claim (7) characterized in that the shoulder of the barrel (1) is reduced by machining to allow passage of the latter inside the breech bars (sua).