Speargun shooting distances

[popgun pete]

Quoted shooting distances from manufacturers are often misleading because they are usually talking about different measurements. For example in Soviet-era speargun specifications there is the "flying range of the harpoon" and the somewhat shorter "range striking target", or kill distance, sometimes termed as a defeat distance, for a given chamber pressure in the gun. No doubt if any speargun failed to meet its specs, or the manufacturer was guilty of handing out misleading numbers, those concerned would be hauled up before Soviet officialdom to explain themselves (State ran companies manufactured all consumer sporting goods). An example is the Russian "Prizm" 70 cm model http://forums.deeperblue.com/pneumatic-spearguns/94639-russian-1-pneumatic-speargun.html (which was sold in the USA for a time by "Klondike Imports") has a handbook specified "Maximum range flying harpoon in water under pressure of air in chamber of gun P = 15 kg/cm2" of 10 metres! Whereas the "Maximum range striking target under pressure of air in chamber of gun P = 15 kg/cm2" was given as 5 metres, so a very big difference! Maximum internal gun pressure allowed for the "Prizm" was 20 kg/cm2, if you could load it as the gun has a high compression ratio with a 30 mm OD tank and a 14 mm ID inner barrel!

In reality there should probably be three range figures specified; i.e. maximum flying range of the spear until it drops to the bottom, the range at which it will actually kill something and the near linear trajectory range where the spear hits without allowing for any drop in the aiming point, assuming that the gun is accurate in the first place.

I guess that when diving in a restricted (in terms of open space available to swim around in) area of limited underwater visibility, say in a river or a lake, the "flying range of the harpoon" was of interest as divers needed to keep that order of separation between them or risk being hit by a stray shaft coming out of the murk surrounding them. Long range guns would not be very safe in such conditions as even if the shooting line limited the flight of the shaft it only needs to snap to send the shaft a couple of metres further out.

 

[foxfish]

I dont how much differance the guns elevation would make to the flying range underwater?

 

[popgun pete]

I dont how much differance the guns elevation would make to the flying range underwater?

Apparently gun elevation can increase the "kill" range by lobbing the shaft in a gun that has insufficient power for the shaft weight that it is trying to throw at that distance. The "Prizm" guns seemed to have up-tilted muzzles and if you are cynical you may think that was to squeeze a bit more distance out of them to meet the official range specs, however that would be without any accuracy unless the target was at exactly the right distance where the spear descended on its parabolic curve through the aiming point which was what you were pointing the gun at. Wherever that convergent point's location in terms of distance from the muzzle was I never found it on my "Prizm" gun and I was not prepared to loose off enough shots to work out where it would be. On a "Spearfisherman Magnum" (sixties vintage) which I acquired some years ago there is a rear ring sight above the handle, I couldn't see how it worked, but Jack Prodanovich said that it was for aiming by sighting the spear tip through the ring sight and that would then let the gun hit a fish at 12 feet. So that has to be true for a parabolic curve shot because the gun must be tilted upwards slightly to produce that sighting line onto the fish. This was back in the days of much weaker bands trying to heave a 3/8" diameter shaft at large fish in the sixties. The Swimaster produced "Spearfisherman Magnum" was actually a slightly restyled copy of Jack's own gun, he gave them one of his grip handles to copy, but they made a mess of it and put the trigger in the wrong spot with respect to the safety mechanism. Jack's own gun, which he kept producing for decades, originally had a ring site as well, but it was omitted on the later guns. The guns can all be seen here: http://speardiver.com/spearguns-polespears-slings/4726-jbl-guns-4.html.

 

[Alphamic]

Just a suggestion and it might be a little far fetched.

Why dont spearing magazines test guns like the hunting magazines do. For example, in a swimmimg pool they can set up guns 1mtr of the bottom with the bullseye also 1mtr of the bottom and test guns. Set targets at various ranges 3mtr, 4mtr etc. In a controlled environment lke a swimming pool test results would be pretty precise. They can measure shaft drop, penetration. The list goes on.

These tests would offer the magazines credibility, transperancy and probably increased sales. Furthermore they could set an industry benchmark for the way guns are tested forcing manufacturers to lift their game and not stretch the truth.

Im sure any of the large magazines could afford to do this, considering the newstand prices they charge.

I know if I was in the market for a new gun I would appreciate an unbiased ballistics test. I would buy the magazine to read it and so would many others. The key would be to test each new gun the same way. Same cord or nyon. Same rubbers or air pressure specified by manufacturer.

I dont know if this has been done before. Let me know your thoughts.

 

[mishu1984]

Just a suggestion and it might be a little far fetched.

Why dont spearing magazines test guns like the hunting magazines do. For example, in a swimmimg pool they can set up guns 1mtr of the bottom with the bullseye also 1mtr of the bottom and test guns. Set targets at various ranges 3mtr, 4mtr etc. In a controlled environment lke a swimming pool test results would be pretty precise. They can measure shaft drop, penetration. The list goes on.

These tests would offer the magazines credibility, transperancy and probably increased sales. Furthermore they could set an industry benchmark for the way guns are tested forcing manufacturers to lift their game and not stretch the truth.

Im sure any of the large magazines could afford to do this, considering the newstand prices they charge.

I know if I was in the market for a new gun I would appreciate an unbiased ballistics test. I would buy the magazine to read it and so would many others. The key would be to test each new gun the same way. Same cord or nyon. Same rubbers or air pressure specified by manufacturer.

I dont know if this has been done before. Let me know your thoughts.

this has been done by hawaii skin diver magazine if im not mistaken. google speargun comparison and be ready to sift through a bucketload of results

 

[tromic]

Shooting distance of pneumatic spergun is in range 3 - 5 times the lenght of the gun. For any manufacturer or any brand of gun. Would it be more or less depends mainly on the setup: shaft used, line slide, kind and thickness of the line. More hydrodynamic shaft with less drag means more range. Vacuum barrel gun has about 25 % more energy than water barrel gun. Using vacuum barrel gun with best setup you will have range about 5 x the lenght of the gun. On effective shooting range the energy of the shaft should be at least 15 - 20 J and the time from shooting to reaching the target not more than 0.25 s. Required energy depends on the size of the fish.

 

[popgun pete]

There have been tests by spearfishing magazines, usually with band guns, I don't recall a test by them of pneumatic guns, but these are not very in-depth examinations, maybe a few shots per gun by different users and then a couple of lines of comment on each, often pertaining to accuracy. To do a lot of shooting and take measurements in a controlled fashion is a big job and magazines usually do not have the resources, they are often produced by a relatively small number of people despite appearances to the contrary. Also magazines do not want to alienate their potential advertisers, so there is a reluctance to be overly critical unless a gun is a complete load of junk, in which case by the time you read about the gun it will be in the clearance sales bin or will have disappeared. The manufacturers are the people who could do it, but maybe the results are not always something they want to talk about as gains in performance may often be not that great, even after a lot of investment on new tooling. Perceptions are often more important than reality, so why destroy the illusion created by marketing men? However distance gauging shots and associated travel arc description may be easier to carry out as I would expect the variability for a given gun would be small, thus requiring less shots per gun for the tests.

 

[Alphamic]

I think the key is marketing. Every dry land hunting magazine does ballistics tests etc and all the gun manufacturers still advertise with them. Why? Because these magazines are the only true form of marketing available to them. To another extent the motor magazines and boat magazines do the same thing. Most car manufacturers know their vehicles will be put through an independant testing phase and thats what keeps them at the forefront of desighn and innovation.

To another extent so are these types of forums but remember most of us who participate here also read these spearhunting magazines. Im not saying the smaller publications can afford to do some tests but the larger international ones im sure can. Considering that these tests would definetaly increase sales.

Furthermore, as originaly stated it would be the truth barometer associated with gun manufacturers. It will force them to innovate and make sure their guns work as per customers expectations. From reading threads in these forums you can see that there are many inferior guns in the market, past and present. As the sport of speardiving increases so will interest in purchasing guns. Therefore so would sales in associated magazines increase.

It would be interesting to know the actual sales figures regarding spearguns and associated products wordwide. I wouldnt be surprised if its more than we all think. Look around, most countries in the world that have a coasline have a strong speargun following, which I believe is increasing. Just lke land based hunters (who are under the strongest pressure) sales in guns are increasing.

It would take someone in these magazines to do proper tranparent tests. Sure it might alienate certain people and cause loss of sales for some manufacturers but dont you think it would force them to pick up their act. If they dont they wll perish and that means that inferior products will eventually cease to be as prevelant as they are now.

Im sure there are many guys looking at purchasing new guns and would like informative tests to help them make a decision. If your products good you wouldnt have any issue with it being made available for testing. Would you?

These are just my thoughts and not intended to offend manufacturers. There are many well respected guys out there and we know who they are. Neither is this intended to offend the small home made guns and parts available. I believe these small guys are the innovators as they build out of passion and love of the sport. I mean look at Tromic and others just like him and see what they have achieved in terms of innovation. All out of passion.

Anyway let me know your thoughts.