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Question about accuracy in long vs short spear

John Marr

Well-Known Member
Aug 1, 2007
64
8
48
Hello,
I am still optimizing my selfmade railgun, trying to figure out if a longer or a shorter spear delivers better accuracy if given the same barrel length and rubbers.
I am comparing 115 vs 85 cm at the moment. Obviously with the longer one I can get a bit closer but the shorter one has way better maneuverability, especially with fish like Cero which might come very close at times.
I guess the longer spear would hold its path in the water a bit better, right?
 
OP
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J

John Marr

Well-Known Member
Aug 1, 2007
64
8
48
Ah. Thanks. I guess I'll build a target and then compare both of them with multiple shots and distances
 
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Benthic

Member
Aug 7, 2015
9
0
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Destin, FL, USA
Shorter will be more rigid and less prone to shaft whip, but have less mass and sometimes people don't like the short overhang because it gives a different sight picture. On personal guns I usually prefer to go to a short overhang but slightly larger diameter shafts
 
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John Marr

Well-Known Member
Aug 1, 2007
64
8
48
Hmm, also I am a rather small guy, so loading shorter guns is easier.
I shall try a 7mm maybe.
Did you do some comparisons?
 

hteas

Well-Known Member
Mar 9, 2005
903
106
148
71
Anchorage, AK
Come to any conclusions?
For me, the gun and shaft length both can cause instability. I tried to use a 120x6.5 shaft on a 90cm Rob Allen gun with horrible results. It was both inaccurate and noisy. I shifted to a 130x6.5 and suddenly everything was back to wonderful.
I have a 60cm Rob Allen for poor vis, and it has a 90x6.3 that is very accurate.
My guess is that changing the power of a gun, brand and model, shaft length and diameter, probably shaft material, and magic all play a role.
 

Mr. X

Forum Mentor
Staff member
Forum Mentor
Jul 14, 2005
7,181
1,363
418
Sunny Britain
Subjectively I feel more accurate when using a longer gun/spear. But I often spear in poor vis., In such conditions a shorter gun/spear feels more manoeuvrable and a better choice. I think 40cm longer than the barrel length is normal to prevent droop in the middle but obviously less critical for railguns and shorter barrel lengths. But I note that RA railguns ship with +40cm spears.

My current spearguns came with, I believe, +35cm spears. I like that for my 75cm speargun, seems less appropriate for the 90cm speargun but both work well.