referring now in greater detail to the drawings , fig1 and 3 illustrate a hand gun 10 is shown as being of the slide action automatic pistol type comprised of , for example , a receiver body or housing 12 having a hand grip portion 14 , trigger 16 , trigger guard 18 , grip safety lever 20 , grip stock 22 and hammer 24 . a slide 25 , carried by the receiver housing 12 also generally contains a barrel 26 therewithin as well as a recoil spring 28 and recoil spring plug 30 . front and rear sights may be provided as at 32 and 34 . the general structure and operation of slide - type automatic pistols is well known in the art and suffice it to say that the slide 25 will move axially with respect to the barrel 26 during cocking and firing of the firearm . as generally depicted in fig1 and 2 , the recoil spring 28 and recoil spring plug 30 are received generally between the barrel 26 and receiver 12 with the recoil spring plug 30 being axially received through a forwardly directed open passageway 36 formed in a forward lower depending portion 38 of slide 25 . as will be noted , the spring plug 30 is provided with an axially extended recess or chamber 40 formed in its inner end to receive one end of spring 28 therein , while the outer end of plug 30 is formed with an axially extending cylindrical portion 42 as to thereby define a generally annular shoulder - like area 44 thereabout . a muzzle brake , embodying teachings of the invention , is shown at 46 as being operatively assembled and secured to the pistol 10 . as illustrated in fig1 - 7 , the muzzle brake 46 is shown as comprising an axially elongated tubular body member 48 with a first body portion 50 intended to be disposed generally forwardly of the pistol 10 and a second body portion 52 intended to be closely slidably received within the cooperating clearance passageway 54 formed in and provided by the slide 25 of the pistol 10 . generally intermediate or joining such inner and outer body portions 52 and 50 is an abutment and locking portion comprised as of an outwardly radiating shoulder 56 which blends with a plate or blade - like radiating extension 58 which has an arcuate recess or relief 60 formed at its generally outermost end . in the embodiment disclosed , the pistol 10 of of the type which has a bayonet - type locking slot or groove 62 formed at the forward end of the slide 25 . such slot or groove may be the one often employed for axially retaining a forwardly disposed barrel bushing for permitting relative axial motion as between the slide 25 and gun barrel 26 . the cross - sectional view of fig3 is one which is taken through such arcuate bayonet - type locking slot 62 . generally , the lowermost ( or right - most ) portion of such slot would have a forwardly directed clearance opening permitting the insertion therethrough of a related key member which , once received within the slot could be rotated clockwise ( as viewed in fig3 ) as to thereby axially contain such key within the left - most portion of the slot 62 . as best seen in fig5 and 7 , a bayonet locking key portion 66 is formed and carried by rearward or inner body section 52 generally rearwardly of the abutment portion 56 . further , in the preferred embodiment , the contour of arcuate portion 60 closely approximates the cylindrical contour of cylindrical extension 42 of spring plug 30 . also , in the preferred embodiment , the muzzle brake 46 is provided with an internally disposed annular bushing or bearing surface 68 which serves to closely slidingly engage the outer diameter of gun barrel 26 . generally , the muzzle brake 46 is assembled to the pistol 10 as by inserting inner end 52 of muzzle brake 46 into aperture or passageway 54 of slide 25 in such a manner as to have key 66 aligned with the clearance passageway leading to the arcuate bayonet slot 62 . with the muzzle brake 46 thusly positioned and axially pushed toward the slide 25 , shoulder or abutment portion 56 will abut against the forward end 70 of slide 25 while key 66 will become positioned within and aligned with the slot 62 . at this time , the blade extension 58 will be angularly disposed as to have its mid or medial axis 72 coincident with line 74 as generally depicted in fig3 . once the muzzle brake assumes such position , the spring plug 30 is manually depressed inwardly of slide 25 , as to thereby push cylindrical extension 42 out of the path of rotation of blade extension 58 . the muzzle brake 46 is then rotated within passage 54 , clockwise as viewed in fig3 until the medial axis 72 again assumes a substantially vertical position as generally depicted at 72 &# 39 ; of fig3 at which point the spring plug 30 is released resulting in cylindrical extension 42 thereof becoming nested by or peripherally contained by the contoured surface 60 while annular shoulder 44 axially abuts against the juxtaposed axially disposed surface 76 of blade extension 58 . it should be apparent that while muzzle brake 46 is thusly being rotated clockwise ( from position 74 to position 72 &# 39 ;), key means 66 is being simultaneously rotated within arcuate bayonet or key slot 62 towards the opposite end 64 thereof and thereby becoming axially locked within such slot . the cooperative abutting action as between contoured surface 60 and cylindrical extension 42 , of course , prevents the unauthorized counter - clockwise rotation ( as viewed in fig3 ) of muzzle brake 46 . as seen in each of fig1 , 4 and 5 the wall structure 77 of muzzle brake 46 has opening means formed therethrough as by a first plurality of slots 78 formed through wall 77 along the generally upper portion of body section 50 . as can be seen , a second plurality of slots 80 are also formed through upper portion of body section 50 as to generally meet or interact , respectively , slots 78 . as best can be seen in the top plan view of fig4 slots 80 are , in the main , located on one side of a vertical plane passing through the centerline 82 , while slots 78 are , in the main , on the other side of such plane . further , each of the slots or aperture means 78 and 80 are so formed as to be generally inclined , when viewed in fig4 whereby their respective points of meeting or intersection are at distances further from the abutment 56 than the distances at which their respective other ends are from the same abutment means 56 . in fig8 and 9 , all elements shown which are like or similar to those of fig1 - 7 are identified with like reference numbers provided with a suffix &# 34 ; a &# 34 ;. as can be seen , the muzzle brake 46a has aperture or venting means , formed in and through the uppermost portion of body section 48a , comprised of a generally medially situated axially elongated slot 90 and a first plurality of axially spaced generally semicircular apertures 92 , generally along one side of and spaced from such slot 90 , and a second plurality of axially spaced generally semicircular apertures 94 along the other side of and spaced from slot 90 . in fig1 and 11 , all elements shown which are like or similar to those of fig1 - 9 are identified with like reference numbers provided with a suffix &# 34 ; b &# 34 ;. as can be seen , the muzzle brake 46b has opening or aperture means formed in and through the uppermost portion of body section 48b , comprised of a first plurality of slots 96 and a second plurality of slots 98 as to generally respectively meet or intersect . as best can be seen in the top plan view of fig1 , slots 96 are , in the main , locate on one side of a vertical plane passing through the centerline 10 while slots 98 are , in the main , on the other side of such plane . further , each of the slots or aperture means 96 and 98 are so formed as to be generally inclined , when viewed in fig1 , where by their respective points of meeting or intersection are at distances closer to the abutment portion 56b than the distances at which their respective other ends are from the same abutment means 56b . fig1 , a view somewhat similar to fig2 illustrate a further modification of the invention . in fig1 , all elements of the muzzle brake shown which are like or similar to those of fig1 - 11 are identified with like reference numbers provided with a suffix &# 34 ; c &# 34 ;. as can be seen , in the embodiment of fig1 , the forward or outer body section 50c is of a size substantially enlarged , in cross - sectional configuration , from that of rearward or inner body section 52c . the venting aperture means generally typically illustrated at 102 , may be of any suitable configuration . fig1 and 14 illustrate further aspects of the invention . the elements shown in fig1 which are like or similar to those of fig1 - 12 are identified with like reference numbers provided with a suffix &# 34 ; d &# 34 ;. the embodiment of fig1 contemplates a muzzle brake 46d being comprised of , for example , three sections the outer or forward most being a tubular member 50d which is soldered , welded brazed ( as generally depicted at 104 ) or otherwise secured to the abutment means 56d which may be comprised of a member such as that shown at 106f of fig1 . the inner or rearward tubular body section 52d may similarly be secured to the rear of member 106f as to be in alignment with body member 50d and member 106 . further , the embodiment of fig1 contemplates the provision of cut - out portions 108 in the wall of rearward body section 52d as to thereby provide for some limited degree of resilient deflection thereof and enable a relatively tight fit as between the outer surface thereof and the inner surface of the pistol such as at 54 of fig2 or 12 . even though not shown , the generally upper portion of forward body section 50d is , of course , provided with any suitable venting aperture means as , for example , already disclosed and described . the elements shown in fig1 which are like or similar to those of fig1 - 13 are identified with like reference numbers provided with a suffix &# 34 ; f &# 34 ;. the embodiment of fig1 contemplates a muzzle brake 46f being comprised of a tubular body 48f and a member 106f which are cooperatively assembled and secured to each other as by , for example , brazing . that is , it is contemplated that the outer surface of tubular member 48f would be closely received within the cooperating inner surface 110f of member 106f and positioned as to have a relatively longer forward body section and relatively shorter rearward body section . in fig1 , wherein all elements of the muzzle brake shown and which are like or similar to those of the preceding figures are identified with like reference numbers provided with a suffix &# 34 ; g &# 34 ;, the rearward or inner tubular body section 112 of muzzle brake 46g is shown as having a threaded portion 114 which cooperatively threadably engages an internally formed threaded portion 116 of the related pistol 10g . preferably , a cylindrical pilot diameter 118 is closely received by a cooperating locating or piloting cylindrical bore 120 as to obtain the best concentricity as between the internal cylindrical surface of such forward and rearward body sections 50g and 122 respectively with respect to the bore of the related gun barrel . if desired , suitable related shimming means 124 may be provided as between the abutment means 56g and the juxtaposed forward end of the pistol in order to assure that the aperture venting means , typically depicted at 126 , will be positioned upwardly when the abutment means 56g is threadably locked against the pistol 10g . fig1 , 17 and 18 illustrate yet another embodiment of the invention . all elements of the shown muzzle brake which are like or similar to those of the preceding figures are identified with like reference numbers provided with a suffix &# 34 ; k &# 34 ;. the muzzle brake 46k is shown as comprising aperture or venting means , formed in and through the uppermost portion of forward body section 48k with such venting means , in turn , comprising a generally medially situated axially elongated slot 130 and a first plurality of axially spaced generally circular apertures 132 , generally along one side of and spaced from such slot 130 , and a second plurality of axially spaced generally circular apertures 134 along the other side of and spaced from slot 130 . further , as can also be seen , the forward most end 136 of muzzle brake 46k is formed as to be inclined and as to have the uppermost end thereof closer to the abutment means 56k . in one particularly successful embodiment of the invention shown in fig1 , 17 and 18 , the angle , &# 34 ; x &# 34 ;, of inclination , from the vertical , of the forward - most end 136 of muzzle brake 46k was in the order of magnitude of approximately 15 ° to 20 °, while the distance , d , from the abutment surface 56k to the rearward end of slot 130 was in the order of magnitude of approximately 1 / 4 inch ; the length , l , of the slot 130 was in the order of magnitude of approximately 1 - 1 / 16 inches and the distance , d &# 39 ;, from the forward - most end of the slot 130 to the top - most portion of the forward end 136 was in the order of magnitude of approximately 9 / 32 inch , while the width , w , of slot 130 was in the order of magnitude of approximately 1 / 4 inch . further , in such particularly successful embodiment , the circular apertures 132 and 134 were each in the order of magnitude of approximately 3 / 16 inch in diameter , substantially axially equally spaced from each other and located as to have their respective centerlines 138 and 140 at angles 142 and 144 of approximately 45 ° with respect to the horizontal when slot 130 is medially vertically disposed as generally depicted in fig1 . it has been found during testing and experimentation that the use of the invention provides an excellent means of effectively producing a pneumatic type brake resisting the otherwise twisting motion or upward kick usually experienced upon firing of the associated gun . that is , the gases produced upon ignition of the propellant in the bullet assembly escape , at least to a great part , through the upwardly directed aperture or venting means formed in and through the upper portion of the muzzle break . in being thusly directed upwardly , an equal and opposite pneumatic reaction force is developed downwardly against the closed lower - most portion of the forward body section tending to thereby push the forward portion of the associated gun downwardly and in such manner overcomes the force moment couple previously described and created by the firing of the gun tending to cause the gun to have said upward kick . further , since the muzzle brake of the invention has its forward most body section disposed forwardly of the associated gun , the downward reaction forces have an increased effective lever arm which , by multiplication , increases the effective reaction force moment couple . during such testing and experimentation it has also been discovered that when the muzzle brake of the invention is employed in combination with a slide - type automatic pistol , the recoil force , as experienced by the operator , is considerably reduced or softened . this is believed to occur because the gases start to escape upwardly through the venting means of the muzzle brake before the slide of the pistol is acted upon . in comparison , without the muzzle brake of the invention , the pistol slide comes back very fast and very hard to the feel of the operator . as may already be surmised by the disclosure hereinbefore made , the invention may be practiced in various configurations . that is , it may be a single unitary piece machined or otherwise formed as to have the desired configuration , or it may be formed of , for example , three pieces secured to each other as generally depicted in fig1 , or it may be formed of a single tubular member generally fitted within suitable abutment means such as depicted generally in fig1 . further , although not specifically shown , it should be apparent that the muzzle brake of the invention could also be made of a single tubular member with a stepped - like shoulder or abutment portion ( functionally equivalent to portion 56 of fig2 ) machined or otherwise formed thereon . even though the key locking means 66 as shown in fig3 , 6 and 7 for purposes of clarity has not been shown in the other embodiments , such may be assumed to exist in , for example , the embodiments of fig8 , 10 , 11 , 12 , 13 , 14 , 16 , 17 and 18 . this is not to say that the invention cannot be practiced without such locking means or with other types of functionally equivalent locking means . further , it has also been discovered that even though various embodiments of the invention are possible and produce perfectly acceptable results , in situations where the muzzle brake of the invention is employed in combination with a slide type automatic pistol , optimum results are apparently obtained when the internal diameter of the forward - most or outer body section of the muzzle brake does not exceed the outer diameter of the barrel of the slide - type pistol by more than approximately 1 / 10 inch . also , during testing and experimentation it has been determined that apparently optimum results are obtained if the effective overall length ( ol ) of that portion of the muzzle brake disposed forwardly of the associated gun is not greater than in the order of magnitude of 2 . 0 inches and not less than in the order of magnitude of 3 / 4 inch . further , even though in the preferred embodiment of the invention , when employed in combination with a slide - type automatic pistol , a bearing surface such as at 68 of fig2 is provided , with such bearing surface 68 having an internal diameter smaller than the internal diameters of both the forward and rearward body sections , a suitable bearing surface for the related barrel may be of substantially longer axial length as generally depicted in fig1 wherein substantially the entire internal cylindrical surface 79 of the rearward or inner body section 52c is employed as a bearing surface for gun barrel 26 . also , while it should be obvious that the muzzle brake of the invention may be constructed of any suitable metal such as , for example , steel or aluminum ( and alloys thereof ) it may not be obvious that the muzzle brake of the invention may also be constructed of plastic . during testing and experimentation it was discovered that many plastic materials are suitable . for example , and not by way of limitation , it has been found that plastic materials such as delrin and lexan are suitable . &# 34 ; delrin &# 34 ; is a trademark of the e . i . dupont de nemours & amp ; co . of wilmington , delaware , for an acetal resin derived by polymerization of formaldehyde . &# 34 ; delrin &# 34 ; acetal resin as tested by the astm ( american society of testing materials ) under standard conditions exhibited a tensile strength , at 75 ° f ., of 10 , 000 . 0 p . s . i . &# 34 ; lexan &# 34 ; is a trademark of the general electric company of 1 river road , schenectady , n . y . for thermoplastic carbonate - linked polymers produced by reacting bisphenol a and phosgene . although only a preferred embodiment and selected modifications of the invention have been disclosed and described , it is apparent that other embodiments and modifications of the invention are possible within the scope of the appended claims .