The following is an excerpt from a article I authored and published about 20/25 years ago. Might be helpful in understanding the difference between a "power head" and a "bang stick"---there is a huge difference!
Power Heads
by Dr.Samuel Miller
The "power head" and the "bang stick" are not synonyms, though they could be considered distant cousins. Both use a gunpowder cartridge, but the similarity ends there. The powerhead is shot from a speargun and uses the cartridge to force a dart through the fish. The bang stick is uses the cartridge's concussive effect to kill the fish.
Power heads
The power head was a point-impact spear point which contained a propellant, generally a .22 caliber or .38 caliber shell, which when fired, drove a spear point called a "dart" into and hopefully through the fish. There were two separate lines on the gun: one a shooting line, the other attached to the dart. The dart line was in turn attached to probably 200 feet of W.W.II of surplus parachute line which terminated in an inflatable device generally a surplus W.W.II Mae West. This component was contained in a "line pack," which was some how attached, generally via bands, to the barrel of the gun.
The "power head" which is distinctly unique to Southern California, was developed in San Diego in the 1940s by the grand old man of Spearfishing Jack Prodanovich. Jack's model was small and compact. It was powered by a .22 caliber rife shell and was unique in that it was cocked by the inertia of firing. A very desirable feature since it eliminated the need to cock it or carry it armed. Those that know Jack well realize that in addition to having hearing problems like all divers of the Viagra generation, he is blind in one eye. This was caused by the power head being rebounded back to him when he was test firing it in a swimming pool. Jacks account of this accident can be found in a 1950's issue of Skin Diver Magazine.
Herb Sampson, of Costa Mesa, California was second to developed a power head. Herb's was big and massive and propelled by a .38 caliber pistol shell. Like his spear gun it had unique threads on the shaft - 1/4-24 (as I recall,) so it could only be attached to his gun if adapters were used. The gun, with its twin line releases, his special line pack, and the power head were "the gun" for a number of years, and at one time held more world records than any other spear gun. (Which is how the Sampson got the name "World Record Gun" - ed.)
I would be remiss with out mentioning my dear friend Ron Merker who was unbelievable with this gun. Ron established three world records including the blue fin tuna which he held for 20 plus years. I often think about things of long ago, and I just recalled the prices of the Sampson, the gun $37.50,(after I got to know Herb well he sold them to me for $23.10 (don't ask about the 10 cents that was just Herb)) the line pack $7.50 and the power head $37.50
Bill Barada, of Los Angeles, was all over diving in the pioneering days and contributed so much; About a dozen books including 2 hard backs on spear fishing, the original dry suit, developed the Hammer head muzzle for the Arbalete, established the Neptunes spearfishing club, etc., the list goes on and on. He also developed the .38 caliber "Thunder Head" power head. It was his biggest failure. Both the Prodanovich and the Sampson power heads had triggering mechanisms that extended about a foot in front of the unit and acted as a trigger when it came in contact with a fish. The Thunder Head relied on the point making contact with the fish exactly like the bang stick. As taught in freshman physics every action has an equal and opposite reaction so the arrow being free flight would often, by the laws of physics, be propelled back at the diver if the object that was struck was hard or impenetrable. Even though it was a dismal failure and was on the market for a short time, there is a picture of this unit in the 1950's book "Dive" by the Carriers. I can't recall a good picture of the Prodanovich or the Sampson in any book.
So those are Power heads
Rhett Mc Nair, lived in Anaheim, California developed and tried unsuccessfully to market a six shooter bang stick about the time the CO2 powered "Shark Dart" was introduced. only a few of Rhett's were produced, but many Shark Darts were made
My diving buddy at the time the late Jack Waite (note SDM first edition) and I went to a gun dealer, Hy Hunter in Pasadena purchased a very cheap and beat up .38, cut off the barrel, tossed the handles, and allowed Uncle Sam to fabricate a three foot trigger extension which was welded in place of the gun handle. With six .38s available and placed next to a fish's face, it did wonders to persuade the stubborn BSB to surface & Baja fish to exit their holes; they received an an offer they couldn't refuse.
The cartridges were water proofed several ways, they could be coated with finger nail polish, spar varnish or my favorite was a automobile radiator sealant. After one submersion they were always discarded.
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About 1958 the US government got into the act. Power heads were at that time were classified as firearms, since the contained a triggering device, therefore were in the same category as sawed off shot guns, machine guns etc. They were illegal to posses or use. Finally the government decreed that they could be rendered legal IF they were solidly attached to a shaft longer than 18 inches. By that time the age of the power head was passing into history, so the law was essentially ineffective.
SDM
---------- Post added January 8th, 2014 at 04:22 AM ----------
Bang Sticks
The "Bang Stick" was, so far as can be determined, perfected down under in Australia, probably by Wally Gibbons had something to do with it's design. I first recall seeing it in action in the early 1960's at the Los Amgeles Underwater film festival. Aussies presented a movie in which it was used to dispatch sharks. It is composed of a barrel, which holds the propellant, any thing from a small caliber pistol cartridge to a very large caliber rifle cartridge and even 12 guage shoot gun shells, which must have a rim to hold it in place and ample clearance to allow it to freely travel back and fourth in the barrel, and a firing pin to , all of which should be attached to a pole spear-- a long pole spear.
The operation is quite simple, the propellant slides into the barrel and extends out the firing side about 1/2 inch. The back/firing pin which should contain a safety constructed of a cotter pin inserted crosswise is attached to the barrel. When the prey is spotted the cotter pin is removed, which arms the spear. The spear is grasped, the sling stretched to maximum length like a pole spear and released striking the prey. Upon contact the cartridge is driven up the barrel making contact with the firing pin igniting the cartridge and propelling the charge into the prey. Very simple and effective.
It was serendipiously discovered in California that an effective inexpensive Bang Stick could be constructed from items avaliable at the local hardware store using a 20 gauge shot gun shell; (which I am not going to reveal in this article)
I suspect since there is no triggering device on a Bang Stick that they are in a gray area immune to federal and state laws.
SDM
