referring more particularly to the drawings by characters of reference , fig1 a , 5 , 6 and 7 disclose the outline of the gun stock end 10 of a standard rifle or shotgun 11 with the usual barrel , magazine and trigger not shown for simplicity purposes . the details of operation of the gun are not essential to the description of the particular invention , but in general , the firearm or gun may be a single shot or a rapid firing , relatively high powered firearm . in the design shown , the stock of the gun may be formed of a molded plastic although it can be formed of any other suitable material such as solid wood and metal . a recoil mechanism 12 is attached to the gun butt end 13 and comprises first and second relatively movable members 14 and 15 , respectively constructed and connected so that one member may be moved relative to the other under the forces of recoil . as shown in fig1 a , the two members 14 and 15 slidably abut along a plane 16 that slopes downwardly and rearwardly when the firearm is held in a firing position with its longitudinal axis 17 directed horizontally . for optimum performance of the recoil absorber and redirector mechanism the plane 16 should form a deflection angle 18 with the vertical 19 of fifteen degrees or more . during recoil , the recoil force is directed rearwardly and downwardly at the butt of the firearm . without the benefit of a recoil absorber and redirector mechanism , the gunner &# 39 ; s shoulder absorbs the recoil energy ; with the recoil mechanism 12 of the invention attached as shown in fig1 and 1a , the butt of the forearm 11 tends to follow the downward and rearward direction of plane 16 away from the shoulder of the gunner with a substantial part of the recoil energy being absorbed by the mechanism 12 . the energy stored in the mechanism then returns the gun stock to its original position . fig2 - 4 show the interior construction of a first embodiment of the invention . as shown in fig2 member 15 has a wedge - shaped form as viewed from the side that is wide at the top and narrow at the bottom while member 14 is also wedge - shaped but wide at the bottom and narrow at the top . member 15 has a foam or other resilient pad 21 attached to its rearward surface which bears against the shoulder of the person firing the gun , and member 14 has mounting holes through which mounting screws 22 may be passed for attachment to the butt of the firearm 11 . when the mechanism is fully assembled , the slidable bearing faces 23 and 24 of members 14 and 15 respectively abut each other along plane 16 of fig1 and 1a . the vertical alignment of the two members 14 and 15 relative to each other is sustained by means of four sets of tongue - and - groove configurations . as shown in fig2 - 4 , member 15 has two vertically oriented tongues or tenons 25 and 26 at its lower end and member 14 has two vertically oriented tenons 27 and 28 at its upper end . tenons 25 and 26 of member 15 fit slidably into grooves 29 and 31 , respectively , of member 14 when the mechanism 12 is fully assembled while tenons 27 and 28 of member 14 fit slidably into grooves 32 and 33 , respectively , of member 15 . a coil spring 34 in cooperation with the four tongue - and - groove configurations just described holds the mechanism together during rest as well as during recoil . the spring 34 operates within aligned cavities 35 and 36 of members 14 and 15 , its upper end attached to a pin 37 at the upper end of member 15 and its lower end attached to a tensioning device 38 at the lower end of member 14 . tensioning device 38 comprises a rectangular block 39 and a machine screw 41 . block 39 fits slidably within cavity 35 and has an attachment hole 42 for the attachment of spring 34 . it also has a longitudinal threaded bore 43 that receives the threaded end of the screw 41 . the screw 41 enters bore 43 through a clearance hole in the bottom of member 14 , with its head trapped in a cavity 44 so that as the screw 41 is turned into the bore 43 , block 39 is drawn downwardly , increasing the tension in spring 34 . fig5 and 7 provide additional details of the construction of members 14 and 15 . fig5 and 6 are cross - sections taken through tenons 25 and 27 and grooves 29 and 32 , fig5 showing the rest position of member 14 and fig6 showing the deflected position of member 14 during recoil . fig7 is a cross - section taken through the cavities 35 and 36 in which the spring 34 is mounted . as shown in fig5 tenon 27 has a wedge - shaped upper end that interlocks in the rest position with the undercut upper end of groove 32 while tenon 25 has a wedge - shaped lower end that interlocks with the undercut lower end of groove 29 . note that as shown in fig7 the spring 34 urges member 14 upwardly relative to member 15 so that the wedge - shaped upper end of tenon 27 is driven upwardly into engagement with the undercut upper end of groove 23 while the undercut lower end of groove 29 is driven upwardly into engagement with the wedge - shaped lower end of tenon 25 . the spring sustains these conditions , thereby causing the two members to be held firmly together . now when the firearm 11 is fired , recoil force , which has both rearward and downward components at the butt end 13 , causes member 14 to move generally downward relative to member 15 , against the opposition of spring 34 . fig6 shows a terminal condition or a condition of maximum displacement in which the lower end of tenon 27 has reached the lower end of groove 32 and the upper end of groove 29 has reached the upper end of tenon 25 . any further upward movement of member 14 will be coupled directly to the gunner &# 39 ; s shoulder . this undesirable occurrence can be prevented by an appropriate adjustment of spring 34 whereby sufficient energy is stored in spring 34 to prevent the tenons from reaching their terminal positions . following the recoil action just described , the energy that is stored in spring 34 is discharged as spring 34 returns member 14 to the rest position shown in fig5 . the spring 34 has thus been shown to provide a threefold function . it holds the members 14 and 15 together during the rest position , it absorbs recoil energy during firing , and it restores member 14 and the butt end 13 of the gun stock 10 to the rest position . the invention as shown in fig1 through 7 has two important advantages over the nearest prior art . first , it is less expensive to manufacture because it comprises only two inexpensive molded plastic parts , a spring and simple tensioning means . while a number of different plastics or polymers have been found satisfactory , it is preferable that the two members be made from different plastic materials to prevent galling . secondly , the mechanism may readily be disassembled to the stage shown in fig2 by simply moving member 14 downward to release the engagement of the wedged ends of the tenons and then drawing the two members apart against the resistance of the spring . this is an advantage in the event the mechanism needs to be taken apart for cleaning . fig8 and 9 illustrate an adjustment feature that may be added to the mechanism of fig1 - 7 or to similar recoil mechanisms . in order to match the mechanism to different physical dimensions of the person firing the rifle or shotgun , it will be found useful to be able to move the mechanism upward or downward relative to the butt of the gun . for this purpose , an adjustable mounting plate 45 may be attached to the forward surface of member 14 as shown in fig8 . the mounting plate has an overall shape or outline matching that of the forward face of member 14 . it has a centered rectangular depression 46 on its forward surface and a longitudinal slot 47 centered within depression 46 . the mounting plate 45 is secured to member 45 by means of a screw 48 that passes through the forward wall 49 of member 14 , through slot 47 and then threads into a square or rectangular slider plate 51 that fits slidably within depression 46 . the adjustment plate 45 is secured to the butt of the firearm by means of two screws 52 which pass through holes 53 in plate 45 . to mount and adjust the position of the mechanism , the plate 45 is first secured loosely to member 14 by means of screw 48 and slider plate 51 . the plate 45 is then secured to the butt of the firearm by means of screws 52 in an aligned and centered position . to gain access to the heads of the screws 52 , member 14 may be rotated about screws 48 during the mounting of plate 45 . once the plate has been mounted , the desired position of the mechanism is obtained by aligning member 14 longitudinally , moving it upward or downward in the direction of the arrows 54 and then tightening the screw 48 to secure the desired position . a second embodiment of the invention is shown as recoil mechanism 55 in fig1 - 14 . the mechanism 55 again comprises a pair of normally aligned members 56 and 57 mounted on the butt end of a gun stock 58 , one of which is caused to move relative to the other under recoil , with the movable member 56 absorbing most of the recoil energy . as in the case of the first embodiment , the movable member 56 is secured to the butt of the gun stock 58 by one or more screws 59 and the other member 57 has a foam or other resilient pad 61 affixed to its rearward surface which bears against the gunner &# 39 ; s shoulder . the members 56 and 57 may be made of plastics or metal and preferably a different polymer for each member . the salient feature which distinguishes mechanism 55 from mechanism 12 is the stepped and segmented interface 62 between the two member , 56 and 57 . the advantage of the stepped interface is that it permits the realization of a larger deflection angle ( angle 18 of fig1 a ) for a given overall ( forward to rear ) mechanism dimension . for example , mechanism 55 is shown with three segments 63 , 64 and 65 as identified in fig1 . if only a single segment were to be employed with the same slope as that shown for each of the three segments , an additional dimensional increment 66 would be required . this would nearly double the overall mechanism dimension front to back . as indicated earlier , the increased deflection angle that is enabled by the segmented interface significantly improves the performance of the mechanism . while a three segment version has been shown and described , the invention is considered to cover any number of segments including two or more . mechanism 55 also differs from mechanism 12 in regard to the means by which the two members are held in alignment . instead of the tongue - and - groove configurations of mechanism 12 , mechanism 55 employs upper and lower alignment pins 67 and 68 , which extend from member 56 into slots 69 and 71 , respectively , in member 57 . pin 67 is capped by a rectangular tab 72 which extends upwardly from the end of pin 67 . in the rest position of mechanism 55 the tab 72 is driven upwardly into a latching position behind a mating projection 73 at the upper end of slot 69 of member 57 . the two members 56 and 57 are held together by a spring 74 , which is housed in longitudinal , aligned cavities 75 and 76 of members 56 and 57 . the upper end of spring 74 is attached to a pin 77 near the upper end of member 57 and its lower end is attached to a tensioning device 78 of the same type that was described earlier , i . e . device 38 of mechanism 12 . fig1 shows the mechanism 55 attached to the butt end of a gun stock 58 with the mechanism in the rest position . as in the case of mechanism 12 the spring 74 holds the two members in alignment , in this case by urging member 56 upwardly relative to member 57 , its upward travel terminating when pin 67 reaches the upper end of slot 69 with its tab 72 captured behind projection 73 . spring 74 sustains the aligned positions of members 56 and 57 as shown in fig1 until the weapon is fired . the force of recoil is directed rearwardly and downwardly . these recoil force components drive member 56 and the butt end of the gun stock in the direction of line 81 which is seen to be in parallel alignment with the slopes of the interface segments 63 , 64 and 65 . member 56 moves downward in the direction 81 until the tension in spring 74 balances out or until the opposing steps 82 and 83 of members 57 and 56 , respectively come into contact with each other . ideally , spring tension should be adjusted so that the relative motion of the two members stop just short of contact between steps 82 and 83 . following recoil , the energy absorbed by spring 74 returns the mechanism to the rest position of fig1 . although but a few embodiments of the invention have been illustrated and described , it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims .