GUN MOUNT ADAPTER
An adopter is a framework or cradle that holds a hand-held gun. When attached to a gun mount by means of a yoke, the adapter permits the gun to be swung from side to side and up and down.
Most gun mount adapters act as shock absorbers. The entire gun recoils a short distance inside the framework of the adapter against a cushion of springs and fluid or compressed air. This shock absorber keeps the gun steadier and makes it possible to fire it more accurately. Also, the cushioning effect of the adapter increases the life of the gun and mount by softening the shock of the explosions when the gun fires.
There are various gun mount adapters used in the Navy. Three adapters commonly used at present will be discussed in the following pages.
Parts of the Mark 6 Mod 3 1. FRONT MOUNTING BOLT 13. REAR MOUNTING BRACKET 2. PISTON RODS AND EVELETS 14. NUT AND COTTER PIN 3. SPACERS 15. SPADE GRIPS 4. WASHERS, NUT AND COTTER PIN 16. KNURLED SCREWS 5. HYDRAULIC SHOCK ABSORBER NUTS 17. SIGHT MOUNTING HOLES 6. FILLER PLUGS 18. SIGHT MOUNTING BRACKET 7. FRONT FRAME SEPARATORS 19. BACK GUARD ASSEMBLY 8. FRONT FRAME SEPARATOR BOLTS 20. TRIGGER 9. BEARER BARS 21. SAFETY 10. YOKE FITTINGS 22. TRIGGER BAR 11. REAR MOUNTING BOLT 23. TRIGGER BAR SPACER AND SPRING 12. FRONT MOUNTING SLIDES
General Description of the Mk 6 Gun Mount Adapter
This adapter is designed to hold a single caliber .50 BAM gun. The frame assembly has two built-in hydraulic shock absorber units that work somewhat like the oil buffer in the gun. A removable back guard assembly houses the trigger and trigger safety mechanism. Only the pistons and rear mounting slides recoil with the gun. The bearer bars and back guard assembly do not recoil. A bracket is provided for mounting the Mk 9 or the Mk 9 Mod 1 reflector sight.
The yoke for this adapter is supplied by the airplane manufacturer in order that the required angles of fire may be obtained in each particular installation.
the Mk 6 Mod 3
|Remove the back guard assembly (19) by unscrewing the three knurled screws
(16). The easiest way is to loosen the lower screw first; then, remove the back
|Place the gun in the adapter. Replace the rear mounting slides through
the rear mounting bracket (13) and the gun's rear mounting holes. Insert the rear
mounting bolt, tighten the castellated nut, and secure with the cotter pin (14).
On the front mounting bolt install the spacers (3) between the piston rod eyelets
(2) and the front gun trunnion. The washer goes between the nut and the eyelet.
Tighten the nut and secure with a cotter pin (4). Do not tighten the two nuts
mentioned enough to hamper the recoil characteristics of the adapter. Tighten
the front frame separator bolts (8).|
the back guard trigger (20) in the forward position and put safety (21) on SAFE.
Install the back guard assembly by placing it on the rear of the adapter and sliding
it forward. Tighten the two upper knurled screws and then the lower one. Check
the installation by charging the gun and pulling the trigger of the adapter. The
firing pin should snap forward.|
|Install the magazine holder
by placing it on the left side of the adapter so that the tongues are inside the
guides of the gun feedway. Secure the magazine holder with the four bolts and
three nuts supplied with the adapter. Install the Mk 9 or Mk 9 Mod 1 reflector
sight in the sight mounting bracket (18).|Restricted
Parts of the Mark 10 Mod 3
|1. FRONT HAND GRIP||13. REAR HAND GRIP ASSEMBLY|
|2. FRONT MOUNTING BOLT||14. TRIGGER ASSEMBLY|
|3. PISTON RODS AND EYELETS||15. TRIGGER|
|4. SPACERS||16. REAR MOUNTING BRACKET|
|5. WASHER, NUT AND COTTER PIN||17. REAR MOUNTING BOLT|
|6. HYDRAULIC SHOCK ABSORBER UNITS||18. REAR MOUNTING SLIDES|
|7. FILLER PLUGS||19. BEARER BAR SEPARATOR|
|8. YOKE FITTINGS||20. CHEST PAD|
|9. YOKE||21. BACK GUARD SUPPORT|
|10. SIGHT MOUNTING BRACKET POST||22. KNURLED SET SCREW|
|11. SIGHT MOUNTING BRACKET||23. BACK GUARD|
|12. BEARER BARS||24. SHOULDER PAD|
General Description of Mk 10 Series Gun Mount Adapters
All Mk 10 adapters are basically the same and, with a few exceptions, parts may be interchanged. The Mk 10 is designed for the gunner to stand on the right side of the adapter; with the Mk 10 Mod 1 the gunner stands on the left side. Telescopic sight brackets were provided for these two adapters. The Mk 10 Mod 2 is designed for the gunner to stand on the right side of the adapter; with the Mk 10 Mod 3 the gunner stands on the left side. The Mk 10 Mod 2 and Mod 3 have a sight mounting bracket for mounting the Mk 9 or Mk 9 Mod 1 reflector sight.
The Mk 10 type adapter is for a single caliber .50, handheld gun. This is a side firing mount equipped with a spring and hydraulic shock absorbing device. The gun recoils within the mount which has necessitated the design of a sliding trigger in the housing plate assembly and special feed tongues on the magazine holder. This adapter has shoulder and chest pads designed to give maximum control and leverage. Since the gunner moves with the adapter as the gun is trained, the tendency of the eye to move away from the sight is reduced to a minimum.
The following text and illustrations show the assembly of a caliber .50 BAM gun to a Mk 10 Mod 3 gun mount adapter. These instructions will serve as a general guide for the Mk 10 series.
Mounting the Mk 10 Mod 3
Install the housing plate assembly (25) on the right
side plate of the gun. Install the retracting slide assembly of the gun on the
left side plate. (Reverse this procedure if the Mk 10 Mod 2 is used.)
|Loosen the knurled set screw (22) and remove the back guard (23) from
the front mounting bolt (2) and spacers (4) from the piston rod eyelets (3) of
the hydraulic shock absorber units (6). Remove the rear mounting bolt (17) and
rear mounting slides (18) from the rear mounting bracket (16).|Restricted
Install the back guard by sliding it all the way forward in the grooves at the rear of the mount. Screw the knurled set screw located under the mount to lock the back guard in place.
Install the magazine holder by placing it on the mount so that the feed tongues are inside the feedway guides of the gun feedway. Secure the magazine holder to the adapter with the three bolts and four nuts supplied with the adapter.
|Install the Mk 9 or Mk 9 Mod 1 reflector sight mount bracket (11).|
Parts of the Mark 11 Mod 3
|1. FRONT SUPPORT||18. FORE POST|
|2. FRONT MOUNTING BOLT||19. FORE POST BRACKET ASSEMBLY|
|3. PNEUMATIC SHOCK ABSORBER UNITS||20. RINGSIGHT|
|4. PISTON RODS||21. RINGSIGHT BRACKET ASSEMBLY|
|5. BEARER BARS||22. CONTINUOUS FEED UNIT|
|6. REAR MOUNTING SLIDE||23. CONTINUOUS FEED UNIT GUIDE|
|7. REAR MOUNTING BOLT||24. CONTINUOUS FEED UNIT MOUNTING STUD|
|8. LINK EJECTION CHUTE||25. CHUTE AND ROLLER UNIT|
|9. LINK DEFLECTORS||26. ECCENTRIC BOLT|
|10. ARMOR PLATE BRACKET||27, AMMUNITION ROLLER SHAFT|
|11. REFLECTOR SIGHT BRACKET||28. AMMUNITION ROLLER|
|12. REFLECTOR SIGHT SUPPORT ADJUSTMENT ASSEMBLY||29. CONTINUOUS FEED PAWL|
|13. BACK GUARD SUPPORT||30. CONTINUOUS FEED PAWL PIN|
|14. KNURLED SET SCREW||31. BACK GUARD|
|15. HAND GRIPS||32. TRIGGER|
|16. CAMERA SWITCH||33. TRIGGER ADJUSTING SCREW|
|17. MICROPHONE SWITCH||34. SAFETY|
General Description of the Mk 11 Mod 3 Gun Mount Adapter
The Mk 11 Mod 3 is a twin, caliber .30, flexible gun mount adapter. It is an improvement over its predecessors the Mk 11 Mod 1 and Mod 2 in that it has a better positioned bracket for mounting the Mk 9 or Mk 9 Mod 1 reflector sight. The Mk 11 rear ring and Mk 1 Mod 1 front post sights may also be installed as standby sights.
The Mk 11 Mod 3 gun mount adapter is designed to absorb the recoil of two caliber .30, BAM guns by means of pneumatic shock absorber units. During firing the piston rods and rear mounting slides recoil with the gun while the bearer bars and back guard unit remain stationary. This adapter has provisions for mounting face, side and shoulder armor.
A continuous feed unit on the outboard side of each gun insures the straight feeding of the ammunition belt into the gun feedway at all angles of fire. Each continuous feed unit is equipped with a continuous feed pawl, which prevents the ammunition belt from sliding out of the feedway when the cover of the gun is raised. The guns are assembled so that feeding is from the left side for the port gun, and from the right for the starboard gun. The retracting slide assembly must be installed on the feeding side of each gun.
On the top of each hand grip of the adapter is a push button. The button on the left hand grip is a switch for the gunner's microphone. The right hand grip switch operates the gun camera which is installed on the starboard gun.
Right and left link deflectors are installed to cause the ejection of belt links into the centrally located link ejection chute. No provision is made for collecting the expended links or cartridge cases.
The Mk 14 is another twin, caliber .30 gun mount adapter. It is very similar to the Mk 11 Mod 3. It was developed to fit in the nose of PBY-5 and PBY-5a airplanes. The Mk 14 differs from the Mk 11 Mod 3 in that the continuous feed units are closer to the centerline to fulfill clearance requirements. The face armor bracket has been removed and a somewhat different bracket provided to mount a Mk 9 or Mk 9 Mod 1 reflector sight.
Mounting the Mk 11 Mod 3
Remove the latch lock pin, latch lock spring, and latch lock from the back plate group of the gun. Insert the bell crank and spacers supplied with the adapter. The bell crank fits over the latch spring. Reassemble the back plate group of the gun.
the belt holding pawl pin from the gun and install the link deflectors (9) which
are provided with the adapter. Replace the belt holding pawl pin.
|Remove the front and rear mount adapters from the gun. Install the rear mount adapters provided with the adapter. The gun is now ready to be installed.|
Remove the back guard (31) by unscrewing the large knurled set screw (14) on the under side of the back guard and sliding the assembly rearward until free.
Remove the front mounting bolt (2). Remove the rear mounting bolt (7) by removing the cotter pin and clevis pin from the inboard end of the bolt and withdrawing it from the rear mounting slides (6). The adapter is now ready to receive the guns.
Place the guns in the mount adapter making certain that the link deflectors enter the centrally located link ejection chute (8). Insert the rear mounting bolt from the outboard side of the adapter and secure it with the clevis and cotter pins.
G - 90
the trigger safety (34) on "SAFE." Install the back guard by sliding
it into the grooves at the rear end of the adapter. Screw the knurled screw underneath
the adapter to lock the back guard in place. Check to be sure that the rollers
are below the trigger bell cranks.
|Install the right
and left hand continuous feed units (22) and secure them to the mount adapter
by means of the two fiber lock nuts supplied for each unit. The large diameter
of the ammunition roller (28) in the continuous feed unit must always be forward.|Restricted
the slack from the continuous feed units by loosening the eccentric bolt nut and
rotating the eccentric bolt (26). Hold this bolt with a wrench and tighten the
nut again. The continuous feed units should rotate smoothly and easily.
|Loosen the lock nuts and adjust the trigger adjusting screws (33) until both
guns fire together when the trigger is pushed. Tighten the lock nuts and check
the operation. This adjustment must be made each time the guns are removed from
|Install the Mk 9 or Mk 9 Mod 1 reflector sight in the sight bracket (11). Also install the Mk 11 rear ring sight and the Mk 1 Mod 1 fore post as standby sights.|Restricted