roller vs standard gun: a range and penetration test

[renepotvin]

So here it is, a comparison, for real, I did it. This should not be controversial.

These are two guns I made. They are of the same band stretch, well as close as you'll get to make a comparison. I would not look at tiny differences as I explain... I'm sure you'll all agree this is the definitive and absolute truth on the matter

YouTube

[Dbrown]

Nice video and explanations of your opinion. I enjoyed watching the video.

[spearq8]

It is always good to do a sanity check and test your equipment or design. I think you can get better performance out of your classic setup if you go with 2 x 14mm small ID bands on shafts around 7mm and 2 x 14.5mm small ID bands with heavier shafts. There is a lot of power to be gained by simply getting the shaft out in a super stable fashion as this doesn't allow power dissipation as the shaft is travelling. It also makes shots much more accurate. To stabilize shaft you need to make sure your handle is shaped correctly and get your hand up as high as possible to the CG of your shaft. This also dramatically drops the felt recoil of a classic setup.

For a roller you can get more power by using an invert roller system or a fixed line length for a double band double action standard roller system. Rollers have no problem getting good power. With rollers the problem is that when you add power beyond a certain point the shaft becomes unstable. Getting the shaft stable at high loads is a lot more difficult with any roller setup than it is with a classic setup ... but it is possible!

[renepotvin]

I'll do an invert roller video next. I'll crank it up and down, and sideways if necessary. Should be fun.

[renepotvin]

Oh and i'll wear gloves!

[jfjf]

Cool video. Why does your roller band seem to pop loose after a shot? Is it because you have very little pre-tension?

How much tension is the band under after the shaft is fired and the wishbone is caught on the muzzle - assuming the band were still attached underneath the gun.

[spearq8]

Originally Posted by renepotvin

I'll do an invert roller video next. I'll crank it up and down, and sideways if necessary. Should be fun.

Great! and thanks for putting the time to share your testing results! And yes gloves are always a good idea.

[Behslayer]

Hi Rene,

Interesting and simple test. But I'm not sure it is a definitive test..

You know exactly how to set up that Classic Banded Gun.

Not sure of the Rubber Diameter, but figure each band to be @ 350% if it's a Small ID 14.5mm -16mm band.

However, the Roller.. I'm not sure if it is set up properly? I did not notice a loading loop on the band or a Load Assist being used? What was the Band Diameter and Pre-Tension? I know plenty of people who use continuous band single Rollers, and I've seen some pretty thorough tests. Have you ever seen this test?

https://ultimatespearfishing.com/the...ller-gun-test/

From what I know, the Single Band Continuous Roller only works well if there is significant Pre-Tension, ie either double stage loading or use of a Load Assist.

[renepotvin]

I waited years and no one ever made a test that showed any great advantage... now I know why.

As for the loading loop, you don't need one if you use two anchors. Look how I load it.

Minute 8 of this video shows why you don't always need a loop.

http://www.youtube.com/watch?v=3I-o5GWxKGk

[Behslayer]

I didn't see you load the gun? If you are using a 2 stage loading, it should be very tight. How long was the Roller Band?

If you are just looking for a Power comparison, you can probably save yourself the whole Wetsuit and Fins etc and just shoot into a piece of foam on land?

I did show you a test there and that is not a particularly new test, but it seems well thought out.

Ofcourse roller gun systems are interesting. Some Single Full Band Systems seem to shoot well. Ofcourse, it would be difficult to match some of the tests we've seen where Rear Handle Guns are shooting 10mm shafts with extreme power and accuracy at 18-20' without Recoil using a classic band set up?

My disagreement is in the use of the word 'definitive'. Yes. you have amde a rollergun and a classic gun and made a test.

[spearq8]

I think power wise there is no doubt that a roller gun can be made to shoot with as much power or even more power than a 3 banded classic gun. The problem is to get that to shoot accurately at the higher power levels. The roller and double action roller guns seem to not have been able to do that and things have migrated to invert rollers ... but invert rollers also have problems with accuracy at full power. But I recently tested a double roller gun that seemed to perform really well and better than the best invert rollers ... so maybe things will migrate back from invert to classic rollers again ??!! One thing is certain and that is not all roller guns are the same and getting a roller gun to shoot well at full power needs some design changes.

[mclane234]

Originally Posted by spearq8

I think power wise there is no doubt that a roller gun can be made to shoot with as much power or even more power than a 3 banded classic gun. The problem is to get that to shoot accurately at the higher power levels. The roller and double action roller guns seem to not have been able to do that and things have migrated to invert rollers ... but invert rollers also have problems with accuracy at full power. But I recently tested a double roller gun that seemed to perform really well and better than the best invert rollers ... so maybe things will migrate back from invert to classic rollers again ??!! One thing is certain and that is not all roller guns are the same and getting a roller gun to shoot well at full power needs some design changes.

Is there anything in particular you think is causing problems?

[kodama]

Originally Posted by spearq8

I think power wise there is no doubt that a roller gun can be made to shoot with as much power or even more power than a 3 banded classic gun. The problem is to get that to shoot accurately at the higher power levels. The roller and double action roller guns seem to not have been able to do that and things have migrated to invert rollers ... but invert rollers also have problems with accuracy at full power. But I recently tested a double roller gun that seemed to perform really well and better than the best invert rollers ... so maybe things will migrate back from invert to classic rollers again ??!! One thing is certain and that is not all roller guns are the same and getting a roller gun to shoot well at full power needs some design changes.

Could you tell us what roller that was that shot so well Which design features it has that makes it so accurate? I love to hear you saying all these things but without knowing which guns you are talking About there is little practical value for any of us garage speargun builders. Not that i don’t want to take your word for it but i just love to think along.

[spearq8]

I wish I could point to one definitive thing that fixes all roller setups at full power, but it really is a combination of many factors. The idea is simply to stabilize the shaft on exit and make sure it exits flat and not tail up or tail down. As you power up your setup, even the smallest deviation in how power is applied to the shaft gets magnified. I have to say that this is also true for classic setups but somehow with classic setups things are not as critical and you can get away with having things not absolutely perfect and still go full power.

[kodama]

Originally Posted by spearq8

I wish I could point to one definitive thing that fixes all roller setups at full power, but it really is a combination of many factors. The idea is simply to stabilize the shaft on exit and make sure it exits flat and not tail up or tail down. As you power up your setup, even the smallest deviation in how power is applied to the shaft gets magnified. I have to say that this is also true for classic setups but somehow with classic setups things are not as critical and you can get away with having things not absolutely perfect and still go full power.

Yes I understand the principle of having the spear exit super stable.
I was rather wondering specifically which double roller you are referring too in your previous comment?