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A&W Diverter/Cyl Bore/Aimpro/Vang/Cyl w/Flight Control

31K views 38 replies 15 participants last post by  Beaumet 
#1 ·
I have been doing a lot of research recently on differant shotgun tools that have been tried over the years. One item that comes off often is "Duck Bill Spreaders". There have been several versions over the years, but they all seem to origanaly date to the early 70's. Crane Lake is often cited has were they originated and they are cited has being used by the SEAL's in Vietnam and by the Air Force Security Forces.

In each case they are cited as being regulated for use with #4 buck shot. This at first struck me has odd, but has I continued to research it, each of the referance manuals that I have found from the early 70's saw #4 has the best all around load for LE/military shotguns.

I finaly was able to secure a A&W Diuverter from Bill DeShivson TFL and had it installed by kingjoey on a 18 1/2" 590 barrel. Pics below.





I found a large amount of info on the A&W in "The Police Shotgun Manual", by Roger H. Robinson, 1973. Mr. Robinson includes many high speed photos that were provided by A&W Engineering of shot loads coming out of the A&W. Once I check some copywrite issues I will try to include them. Those photos show the divreter appairing to be very efficent at what it does. The accompaning data also outlines Diverter Pattern Control.

For example:
At 10 yards you have a 7 1/2" H x 29" W pattern with #4

At 30 yards you have a 25" H x 96" W pattern with #4.

this does what it was intended to do, in that it increases the chance of hiting a target. Terminal effects are a seperate subject.

They also claim a 22% reduction in recoil. They also claimed that the diverter would diminish the muzzle flash to that of a .38 special at night.

Finaly to my surprise they found that dispite the fact that a slug is larger then the mouth of the diverter, you can fire them through it. The result is two grooves on either side of the slug, and a resulting reduction in yaw.

That's it for now. I should be posting some range results this week.
 
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#3 ·
Lee Lapin THR
Last ones I have seen any reference to were being made at a business called Great Lakes Arsenal by one Chuck Madurski (mgman269@REMOVETHISaol.com ). That's been a couple of years ago, check and see if the email address still works if you want to see about getting one. He made the 'duckbill' spreaders and installed them too, at one time. Don't know if he still does.

Looks to be time for another history lesson... 8^).

According to Swearengen in _The World's Fighting Shotguns_, the US Air Force Directorate of Security Police in the mid-1960s developed a requirement for a spreader choke that would produce a wide elliptical shot pattern. This horizontal pattern spread was supposed to increase the hit probability from a shotgun on a moving target. Recall if you will that the Sixties were a time when the war in Vietnam was heating up, and civil unrest in the US was too. Lots of people in police and military circles were interested in many aspects of weapons both lethal and non-lethal. Shotguns came in for their fair share of attention, especially given their role at the time as the primary law enforcement long gun.

The Air Force request went to Frankford Arsenal for action, at the time Frankford was working on improvements to the military shotgun in general. Early experiments at producing a spreader choke were less than successful- the chokes split, patterned poorly and in various ways failed to produce te desired result. Ultimately Frankford ordnance engineer Charles A Greenwood developed the duckbill choke in answer to the Air Force requirement. It was subjected to a good deal of laboratory and field testing.

The original duckbill choke was simply a sleeve with a long V-notch cut on either side, the apex of the V toward the rear. The top and bottom of the sleeve were compressed toward the centerline at the muzzle, constricting the emerging pattern of shot in the vertical plane and forcing it to spread horizontally. The sleeve was permanently brazed onto the barrel so that it would not be blown off or rotated by firing the gun.

Early examples of duckbill- equipped shotguns were deployed to Vietnam in the hands of Marines and Navy SEALs. It was found that the open V- notches in the muzzle of the duckbill hung up badly on vegetation as the shotgunner tried to move through thick growth, so the duckbill was modified with a ring around its muzzle to exclude vines and branches. It was discovered that the spreader device worked as advertised, but in reality what was needed in a fighting shotgun was a way of producing dense, lethal patterns.

Spreaders in field testing produced patterns five feet high and twelve feet wide at 30 meters with #4 buckshot loads. At 40 meters, patterns were six feet high and sixteen feet wide. At 40 meters an average sized man would only be hit by a couple of pellets. But with a standard cylinder bored barrel shooting approximately a four- foot circular pattern at 40 meters, some 60% of the shot would strike an average man- sized target.

Still, the duckbill choke had its adherents, among SEALS especially. Development on the idea continued for several years. Clifford Ashbrook and Wilson Wing of Kexplore, Inc. in Houston, TX developed the A&W Diverter (pictured in my previous post) in the late 1960s using mathematical concepts, and received patent protection (# 3,492,750) in February 1970. The example I have is marked Patent Pending, I have no idea of its date of manufacture. It is an interesting artifact of a bygone era, I bought it as an oddity (and paid less for the barrel with the device installed than the spreader itself originally cost) and still consider it an oddity. I don't believe it to be practical save in very limited circumstances, but my preference for tight buckshot patterns should be pretty well known here.

Swearengen's last words (copyright 1978) on the concept of spreader chokes are: "It is expected that the controversy over spreaders and diverters will continue. It appears from available data that they will find little employment in actual combat."
Also some photos linked out of THR by ar15hitman:
If you have one and would be interested in trading for an HK 512 gas operated 7+1 shotgun. The shotgun is great but it is more of a collector piece and rare. I need a working man's shotgun that I can roll around in the dirt with. I would feel guilty doing that to the HK even though I know it can take it.

With the info I have gathered it was manufactured by Franchi for HK under a contract to supply an elite force in Germany (GSG9). Also called the "Anti-Terrorist Shotgun" They had an overrun and about 270 which were imported into the the US. These are the only ones known to be in the US. It uses a shot diverter that creates a rectangular spread which I think was also used on Franchi shotguns like the LAW and SPAS back then.



And this from spas12.c0m:
Below is a better look at the spreader or "divertor" (thanks Dennis) which can be seen with target patterns in the 1988 Gun Buyer's Annual article which can be seen on this site here. Note it consists of two parts -- a piece that screws on the end of the barrel and a second piece that screws over the first. Part one is tightened on the barrel, the second rotated till properly aligned and the set screw tightened. (Don't let anyone sell you just part two -- this happened to me!)


 
#4 ·
The mention of that HK design is interesting. I remember hearing about that one (the rectangular pattern).
I saw another version in Europe. I can't remember if it was in France or Germany, but it had the elliptical diverter. However this one could rotate if I remember right so that the pattern could be shot through a narrow arc when less lateral spread was needed. I want to say this was on a Franchi.
However is has been several years since I saw this.
 
#10 ·
Desert01 said:
this does what it was intended to do, in that it increases the chance of hiting a target.
I thought that was what the little sight thingy on top of the barrel was for. :wink:

Interesting write-up.

Personally, I've never seen the need for such a device, but I appreciate your posting about it.
 
#11 ·
So how long do we have to wait for King Armory to put one of these in production? The S-12 modelw ould sell like hot cakes if you let the guys at forums.saiga-12.com know about them.
 
#12 ·
stiletto raggio said:
So how long do we have to wait for King Armory to put one of these in production? The S-12 modelw ould sell like hot cakes if you let the guys at forums.saiga-12.com know about them.
It is in the works, but I doubt we will sell many for Saigas. We have had pretty weak sales on our KA-1212BR for the Saiga and everyone and their mother was begging us to build those :? We also spent a ton of R&D money developing an improved gas tappet for the Saiga and have yet to sell ONE :shock: Seems a lot of the Saiga owners are heavy on talk and nothing else :(
 
#14 ·
I've got something very similar on a mossy 500 barrel. Was built by a retired USMC armorer from KY. He stated the marines used modified shotgun barrels for jungle warfare starting in WWII on South Pacific islands. They would heat the barrels and "hammer" them into an oval shape. The guy states he just took the idea a step further and constructed a barrel end piece. It does look somewhat different, but serves the same purpose. I'll try to gets some pics up in the next few days to add some spice to the post. :)
 
#15 ·
Interesting, I will be waiting. Goes with the common ideal of whats old is new. I have made the comment several times about how some ideals come up has "the thing" found wanting and discarded only to be "rediscovered" again. Mainly because those that had used the ideal found, it wanting and discarded it have passed from the scene.

My A&W is a test peice and interesting piece of shotgun history. Not a defensive piece.
 
#16 ·
My range session was shorterned today due to crowds getting ready for hunting season. I shot Federal #4 2 3/4 Magnum 34 pellet buck for the base load and a small amout of 2 3/4 00 Reduced Recoil Remington. I used the 590 barrel with A&W and a Aimpro modified breaching barrel. Here are the results:



A&W Diverter
7 yards #4

The wad made the large holes at the top.

10 yard #4 is here, not circled, pellets on far right are from the 7 yard shot.

At 10 yards you can see that shot has already spread and at least 4 pellets are off the target.

15 yards #4

Here you have the shot sread far enough to hit three targets, although the effect on two of the three would most likely not be a fight stopper. Even the center target may continue to fight.

7 yards 00

ouch

10 yards 00


15 yards 00 circled in red the 10 yard #4 is here, not circled

Half of the load is off the center target and only 2 pellets hit near the edge of the second target. Is this the Max Effective range?
 
#17 ·
Same Load fired out of the Aimpro breacher:




A few pellets are now off the mark, but the 15 yard target has received around 30 hits ot of 34. A lower aim would have most likely kept this 34 of 34.


Still around 29 hits out of 34 at 20 yards. 17 or so out of 34 at 25 yards Still effective, with more hits then the A&W had at 15 yards on any one of the 3 targets it hit.
 
#21 ·
Was this the buck shot with flight control wads?
 
#22 ·
EBK said:
Was this the buck shot with flight control wads?
No, or at least it doesn't appear to be.
 
#24 ·
FMD said:
EBK said:
Was this the buck shot with flight control wads?
No, or at least it doesn't appear to be.
Did not think so but I had to ask.

For the record the pics of the box of ammo were not in this thread when I looked at it.
 
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