Measuring length.....

[Andrew the fish]

I am looking at this gun here

Total gun length is 40 inches. Band stretch, I am guessing here, maybe 16 inches? I see your point, Bill. But AB Biller 36 is not a 16" gun! This is not a baby speargun. This is a full size 100 cm gun, with piss poor power stroke, is what it is. I said earlier, we need band stretch, right next after the total length, as a matter of saying who is who.

 

[Savagedragon]

OK, I think band stretch is the most important number, someone else thinks total length, etc. But why do we have to choose? Here is a screen shot from the Abellan web site for my Denton 120. It give you everything you need to know. It even tells you how long to cut the rubber for 370% band stretch if you don't know how to compute that yourself.

I know what you mean, Bill... but you have to also consider that your Abellan 122 cm band stretch would definitely change if you use a different spear shaft from the stock spear shaft Abellan supplied you with. Some manufacturers put the shark fin really close to the trigger mech and some put their shark fin further. So yeah I guess your Abellan gun if measured from the trigger mech to the end of the barrel would probably be 124 cm but in this case 1 or 2 cm extra wouldn't make too much difference as far as power goes.

 

[Mr. X]

By band stretch I mean the actual length from the trigger mechanism to the end of the barrel. I guess your bandstretch means the actual real stretch from the wishbone at rest to the trigger mechanism?
This is all confusing because Abellan usually states their band stretch as the way I described : from the trigger mech to the end of their barrel. For example their Abellan 110 has a band stretch of 122cm (used to be 112cm).

I guessed as much. I was kind of making a point that careless/inaccurate terminology and measurements just causes needless confusion. But it seems rife in the global marketplace. I read an article this weekend by Paul Sellers and he made a similar point about some handsaw screws he'd bought which were too short for at least 90% of handsaws!

 

[snask]

So when people are suggesting a 100cm gun for certain conditions, is it total or barrel they refer to?

 

[DivingNomad]

So when people are suggesting a 100cm gun for certain conditions, is it total or barrel they refer to?

Most likely barrel if they are from outside the US wood gun zone.

 

[Mr. X]

Barrel pipe length for pipe spearguns. I think woodies and pneumatics(?) use total length. Woodies total length is also often specified in inches rather than cm (or mm or m).

 

[Savagedragon]

Barrel pipe length for pipe spearguns. I think woodies and pneumatics(?) use total length. Woodies total length is also often specified in inches rather than cm (or mm or m)

Depends what type of woodies. European woodies still typically use band stretch I think, except for Abellen where you get +12cm to your gun size. Carbon spearguns are all over the place but C4 has recently adopted bandstretch.

 

[popgun pete]

I just had the chance to measure two Salvimar pneumatic speargun with a builder's rule which is way easier than using a retractable tape which flops around while you are trying to lock the tape in position. To my surprise the Predathor Vuoto 100 measured 107 cm from muzzle tip to rear valve cap and the Vintair Vuoto (Vuoto Air) 85 measured 92 cm, so that is 7 cm extra in both cases above the nominal length. A Salvimar Vintair 35 single power measures out at 42.3 cm, so again there is that 7 cm difference.

A Mares Cyrano 1.3 blue handle 90 model measures out at 90.7 cm which is more like it, and a Miniministen 2001 model (classed as a 42) measures out at 42.4 cm.

A Cressi Saetta 88 Quasimodo measured from muzzle tip to rear valve cap is 91 cm, so that is only 3 cm different. I am surprised Cressi did not call it a 90, but maybe the marketing people thought “88” sounded better. I don't have one to measure, but it would be interesting to see what the length is for the Predathor Dark Side 99.9!