It is important to understand
the mechanical differences of these guns to see how it will influence
your choice.
Spear sag
A 6.5mm spear with any more than 100cm suspension will have sag,
7mm spears suffer from a similar problem but not as much depending
on the length of the gun, which is more obvious out of the water.
So different manufature’s have tackled this problem in different
ways. Most of the South African spearguns have a rail that runs
the full length of the gun like the barrel in Fig 1.
Fig 1
Then the Euro guns will have a collar like this.
Fig 2
Rails.
Full rails do add mass to a speargun with the barrel being taller
and does affect the speed in which you can turn or pan a speargun
in the water. Another impact is the drag on the spear. Due to the
surface area the spear rests on, this has an impact on the speed
of the spear.
There are different versions of a rail. An extruded
rail which is actually part of the alloy tube.
Fig 3
These barrels are very strong but again add weight and can transfer
a lot of noise from the spear when fired. The sleeve (as shown in
the first picture) is another method, which is a bit quieter, and
quite slippery can sometimes move around on the barrel when the
gun gets a bit older. This method was also used on the Sporasub
Black Viper speargun. Rabitech opted for a separate rail made of
polymer, which was held by adhesives. These rails are slipperier
and quieter than an extruded rail and also a bit deeper which again
has its pros and cons. showen here in Fig 4
Fig 4
A deeper rail can have more resistance on the spear
and a spear with a small kink or bend does not sit in the rail quite
as well. But can also guide the spear more accurately especially
when the spear has a lot of power behind it.
Omer have an after market rail that can be applied
by the consumer. Quite a shallow rail and should only be fitted
to guns with a similar spear elevation. These are great to take
the sag out of a long gun. But don't really keep the spear in place
when holding the speargun on its side.
Fig 5
Then we have the Beuchat
Elite speargun, which has a rail of sorts as part of the carbon
barrel. This is not full length and quite an open channel. This
again takes the sag from the spear but not what I would really call
a rail.
Collars
In most cases collars are adjustable by the consumer and in some
cases they give the option to add a half rap. They have less effect
on weight and turning the gun in the water but they do tend to move
if not fixed tightly to the speargun. In some cases the screw in
rubbers can hit the collar as the gun is fired which would affect
the accuracy.
Muzzles
Most of the South African spearguns have rap around rubber slings
fitted which are forced around a muzzle which aligns the rubber
slings so they are at the same elevation as the spear. This does
make the mass at the front of the gun a bit larger. But on the positive
side it does stop the rubber slings from sliding side to side through
the muzzle when loading the gun.
European guns often have screw in rubber slings which have a thread
at each end of the rubber slings. Which can be easier to change
the bridle.
Weight
Railed spearguns generally are heavier in the water this is partly
due to the rail. Which is either fitted on, or part of the barrel.
But it is also because most South African spearguns are made with
an alloy tube that has a 2mm sidewall where as the euro guns have
about a 1.5mm wall thickness. Which can be a good and bad thing.
Good when it comes to resting the speargun to bait up when diving
as it does not get carried away in the current to easily. Plus a
heavier speargun with the same spear has less recoil. But when lining
up on a fish, the strain on the wrist can affect how accurately
we aim.
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