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Roller Gun Power Boost
- Thread starterNicko
- Start date
Thread Status: Hello
, There was no answer in this thread for more than 60 days.
It can take a long time to get an up-to-date response or contact with relevant users.
It can take a long time to get an up-to-date response or contact with relevant users.
Hi Gregaz
I would recommend as heavy a spear as will fit your gun. A light spear will increase the chance of shaft whip which is the spear flexing like a snake which reduces the range and power of the gun drasticaly. on my 100 cm rollergun I use a 8mm spear which runs in a 7mm deep track so that only the sharksfin sticks out of the track for this reason my shooting line is attached through a hole in the sharkfin.I think your longer spear will be more prone to whip with all that extra power. I cant load my 100cm gun with the rubber on full preload. My gun had 2 anchor points on the underside. The first anhcor point gives about 100mm of preload. The gun is loaded to the back sharkfin then turned over and loaded to the second anchor point for max power if required.
I would recommend not using pinned euro shafts my diving buddies cressi 6.5mm pinned shaft snapped on the pin just before we had a visit from a bull shark.
The offending pinned shaft
multiple anchor points are good for making your gun's power adjustable and easier to load but you cant beat the pulley system for adjusability and ease of loading. I found the the longer rubbers tend to throw off the anchor point pin when fired and some times catch on the front anchor pin almost tearing it out. That is why I added the deflector/retainer which which prevents rubber throw off and also prevents shooting line from snagging the pin. sorry about the blurry pics I must get a better camera phone. I hope this helps you make a decision.
I would recommend as heavy a spear as will fit your gun. A light spear will increase the chance of shaft whip which is the spear flexing like a snake which reduces the range and power of the gun drasticaly. on my 100 cm rollergun I use a 8mm spear which runs in a 7mm deep track so that only the sharksfin sticks out of the track for this reason my shooting line is attached through a hole in the sharkfin.I think your longer spear will be more prone to whip with all that extra power. I cant load my 100cm gun with the rubber on full preload. My gun had 2 anchor points on the underside. The first anhcor point gives about 100mm of preload. The gun is loaded to the back sharkfin then turned over and loaded to the second anchor point for max power if required.
I would recommend not using pinned euro shafts my diving buddies cressi 6.5mm pinned shaft snapped on the pin just before we had a visit from a bull shark.
The offending pinned shaft
multiple anchor points are good for making your gun's power adjustable and easier to load but you cant beat the pulley system for adjusability and ease of loading. I found the the longer rubbers tend to throw off the anchor point pin when fired and some times catch on the front anchor pin almost tearing it out. That is why I added the deflector/retainer which which prevents rubber throw off and also prevents shooting line from snagging the pin. sorry about the blurry pics I must get a better camera phone. I hope this helps you make a decision.
The thickest shaft I can get is a 7.5mm, it's pretty heavy compared to regular shafts so that should be good
Only thing is that is has the mini fins and the line attachment is in the back of the spear. Should I just buy a new spear with large fins to be safe?
Also, I don't have a deep or enclosed track like you so there will probably be a fair amount of whip. Should I meet in the middle and do 17mm bands?
Only thing is that is has the mini fins and the line attachment is in the back of the spear. Should I just buy a new spear with large fins to be safe?
Also, I don't have a deep or enclosed track like you so there will probably be a fair amount of whip. Should I meet in the middle and do 17mm bands?
I would suggest try loading your buddies gun with the 24 inch x 18mm bands in the water as it is harder to load in the water than standing on land. I think the line connected at the back will not be a problem because of the shallow track. your wishbone should lift up on the roller head when it comes to a stop after you fire and the line should clear. I have never used 17mm bands so I cant comment on them. The 16mm bands are much easier to load and the 18mm bands give about 30% more power. I have 16mm bands on my 80cm gun and I have over stretched them to the point of failure(420%) I could not do that with 18mm rubber. I would go for the taller sharkfins I have huge 7mm fins on my spear, the wishbones never slip off, it gives me a bit more confidence when loading such a powerful gun. one of my dive buddies lost the skin of the top of his finger when a wishbone slipped out of a grooved spear and that was a dyneema wishbone, a steel one would have taken his finger off. luckily I have a welder and make my own spears as sharkfins that big are hard to come by.
Really? I thought it would be easier to load in water when you can twist and bend your body in any way necessary to load it lol
That being said, I don't live near him so I can't try his. But loading it will never be an issue. I'm a gorilla and I'll load anything necessary when it comes down to it.
The only reason I was suggesting to get the large shark fins is to have the line attachment in the fin instead of the back of the spear. If you think it will be okay in the back of the spear I'll just use the spears I have... the wishbone won't slip off the mini sharkfins guaranteed.
Thanks for all the useful info! It's greatly appreciated. I'm gonna buy the bands and other accessories today, so when they come and I set them up I'll post some pics and let you know how it goes
That being said, I don't live near him so I can't try his. But loading it will never be an issue. I'm a gorilla and I'll load anything necessary when it comes down to it.
The only reason I was suggesting to get the large shark fins is to have the line attachment in the fin instead of the back of the spear. If you think it will be okay in the back of the spear I'll just use the spears I have... the wishbone won't slip off the mini sharkfins guaranteed.
Thanks for all the useful info! It's greatly appreciated. I'm gonna buy the bands and other accessories today, so when they come and I set them up I'll post some pics and let you know how it goes
I'm interested to see how you go loading with a full preload ie the rubber attached close to the trigger on the underside. Looking forward to seeing some pics when you get the gun made. good luck.
Okay guys, I need some serious help!!
This thing is impossible to load!!
I did the 2ft of 18mm rubber on each side like you suggested and added some preload (about 17cm) and this thing is ridiculous
I'mm sure I'm using the wrong material for the bridle (2.2mm dyneema). I guess I need something like 5m or more. But regardless, with the length of the gun i can't get the bands to even budge from the roller.
So I retied the wishbone (made it shorter), and also put no pretension on the bottom. This time I was able to set the gun... barely.
But my problem is this. If I use virtually no pretension and set the 24" bands to the last notch on the spear I'm getting just about 300% of stretch. (From the muzzle to the sharkfin is 46" so call it 48" and that's 2x the relaxed length which equals 300% right?)
However, if I use a normal setup with a normal muzzle, I would use a 27" 18mm band, and a 24" 16mm band.. and if you calculaate the band stretch for both of those, isn't that WAY MORE power than the roller set up above?
If I calculated right, wouldn't you take half the length of each band, and figure out how much it's being stretched?
So for the 18mm - (27/2 = 13.5 then 46"/13.5= 3.4 which is 340% of stretch
Then the 16mm - (24/2 = 12 then 46"/12 = 3.8 which is 380% of stretch
Someone please explain how this roller gun is better then my regular setup... Did I just waste money trying to make my gun look cool?
This thing is impossible to load!!
I did the 2ft of 18mm rubber on each side like you suggested and added some preload (about 17cm) and this thing is ridiculous
I'mm sure I'm using the wrong material for the bridle (2.2mm dyneema). I guess I need something like 5m or more. But regardless, with the length of the gun i can't get the bands to even budge from the roller.
So I retied the wishbone (made it shorter), and also put no pretension on the bottom. This time I was able to set the gun... barely.
But my problem is this. If I use virtually no pretension and set the 24" bands to the last notch on the spear I'm getting just about 300% of stretch. (From the muzzle to the sharkfin is 46" so call it 48" and that's 2x the relaxed length which equals 300% right?)
However, if I use a normal setup with a normal muzzle, I would use a 27" 18mm band, and a 24" 16mm band.. and if you calculaate the band stretch for both of those, isn't that WAY MORE power than the roller set up above?
If I calculated right, wouldn't you take half the length of each band, and figure out how much it's being stretched?
So for the 18mm - (27/2 = 13.5 then 46"/13.5= 3.4 which is 340% of stretch
Then the 16mm - (24/2 = 12 then 46"/12 = 3.8 which is 380% of stretch
Someone please explain how this roller gun is better then my regular setup... Did I just waste money trying to make my gun look cool?
Its all about transferring the power of the rubber to the spear, with your old setup you had 51 inches in total of 16 and 18mm rubber applying power for 36inches (46 - 14(length of 1/2 rubber plus whishbone)Okay guys, I need some serious help!!
This thing is impossible to load!!
I did the 2ft of 18mm rubber on each side like you suggested and added some preload (about 17cm) and this thing is ridiculous
I'mm sure I'm using the wrong material for the bridle (2.2mm dyneema). I guess I need something like 5m or more. But regardless, with the length of the gun i can't get the bands to even budge from the roller.
So I retied the wishbone (made it shorter), and also put no pretension on the bottom. This time I was able to set the gun... barely.
But my problem is this. If I use virtually no pretension and set the 24" bands to the last notch on the spear I'm getting just about 300% of stretch. (From the muzzle to the sharkfin is 46" so call it 48" and that's 2x the relaxed length which equals 300% right?)
However, if I use a normal setup with a normal muzzle, I would use a 27" 18mm band, and a 24" 16mm band.. and if you calculaate the band stretch for both of those, isn't that WAY MORE power than the roller set up above?
If I calculated right, wouldn't you take half the length of each band, and figure out how much it's being stretched?
So for the 18mm - (27/2 = 13.5 then 46"/13.5= 3.4 which is 340% of stretch
Then the 16mm - (24/2 = 12 then 46"/12 = 3.8 which is 380% of stretch
Someone please explain how this roller gun is better then my regular setup... Did I just waste money trying to make my gun look cool?
The roller gun uses 48inches of slightly heavier 18mm rubber and is applying power for the whole 46 inches.
It should be about 30% more powerful with no or very little recoil and no need to load a second rubber.
You definitely need an intermediate sharkfin. Hold the gun in the chest load position and stretch both your arms along the gun as if you are loading it and mark the spear at the crease where your hand joins your wrist. take the spear down to your local stainless steel fabrication shop and get him to weld a bit of scrap stainless on the mark, borrow a small angle grinder and shape it into a sharkfin, rub smooth with emery cloth or part of an old sanding belt.
Hip load to the intermediate sharkfin then chest load to the back fin
If it is still too hard to load you can always use the pulley system described in the previous posts.
This can be set up so the rubber extends partially down the gun then cranked up to full power after loading. This also has the advantage of fully adjustable power.
I hope this helps
Unless the shaft is really heavy, I like a single 16mm band or better yet a 14mm small ID band.
The small ID 16mm might be ok at 300% or you can crank regular 16mm to 340% and small ID 14mm to 370%
Seeing as the advantage to rollers is that you can accelerate the shaft for longer, I like to use the thinnest rubber that stretches the most without degradation and still gives good shaft speed.
Sent from my iPhone using Tapatalk
The small ID 16mm might be ok at 300% or you can crank regular 16mm to 340% and small ID 14mm to 370%
Seeing as the advantage to rollers is that you can accelerate the shaft for longer, I like to use the thinnest rubber that stretches the most without degradation and still gives good shaft speed.
Sent from my iPhone using Tapatalk
Okay, I think I got it figured out.
I was looking for something that could help me load the rollergun, because even with a intermediate fin, it's just next to impossible to get the damn bands out of the roller muzzle. I think this might also be because the wishbones is a little too long and the bands sit a little deep. Its hard to make the wishbone any shorter tho, because its only like 2 inches (maybe even less). The rails that stop the wishbone at the top of the muzzle are just really low I guess.
Anyways, I saw this thing (link below), and thought that it could really help me. But I would never pay $35 for that!! So I made it for $6. It took 1ft of 18mm rubber ($3), 1ft of dyneema ($0.70) and a gate latch at Home Depot ($2). I cut the gate latch hook a little short because it was longer than needed. And after putting it together this thing works like a charm!! It's like setting a regular looped band. It hangs down far enough for me to comfortably reach it and pull it back. After it's on the notch, I grab the actual roller band and pull that back the rest of the way and the other rubber unhooks itself.
http://www.rollerspearguns.com/product/easy-reach-roller-gun-loader-copy/
ApneaAddict
I'm not sure how heavy my shaft is compared to others of the same size, but its a 7.5mm shaft from Mako. I haven't used any other shaft except JBL and Beuchat, and those are like twigs compared to Mako. I think it's pretty heavy for a 7.5mm shaft (160cm).
That being said, I wanted to do 370% with the 18mm rubbers. I hope that's safe lol.
I mainly want to do it because I take really really long shots, and love overkill. The fish in Jamaica are very timid and don't come anywhere close to divers (due to over fishing and overpopulation of spearos). And it's annoying to dive to 100ft and come up with nothing. Im going to try a range of about 330% to 370% and find the sweet spot. I'll do this by adjusting the preload on the bands.
What are your thoughts?
I was looking for something that could help me load the rollergun, because even with a intermediate fin, it's just next to impossible to get the damn bands out of the roller muzzle. I think this might also be because the wishbones is a little too long and the bands sit a little deep. Its hard to make the wishbone any shorter tho, because its only like 2 inches (maybe even less). The rails that stop the wishbone at the top of the muzzle are just really low I guess.
Anyways, I saw this thing (link below), and thought that it could really help me. But I would never pay $35 for that!! So I made it for $6. It took 1ft of 18mm rubber ($3), 1ft of dyneema ($0.70) and a gate latch at Home Depot ($2). I cut the gate latch hook a little short because it was longer than needed. And after putting it together this thing works like a charm!! It's like setting a regular looped band. It hangs down far enough for me to comfortably reach it and pull it back. After it's on the notch, I grab the actual roller band and pull that back the rest of the way and the other rubber unhooks itself.
http://www.rollerspearguns.com/product/easy-reach-roller-gun-loader-copy/
ApneaAddict
I'm not sure how heavy my shaft is compared to others of the same size, but its a 7.5mm shaft from Mako. I haven't used any other shaft except JBL and Beuchat, and those are like twigs compared to Mako. I think it's pretty heavy for a 7.5mm shaft (160cm).
That being said, I wanted to do 370% with the 18mm rubbers. I hope that's safe lol.
I mainly want to do it because I take really really long shots, and love overkill. The fish in Jamaica are very timid and don't come anywhere close to divers (due to over fishing and overpopulation of spearos). And it's annoying to dive to 100ft and come up with nothing. Im going to try a range of about 330% to 370% and find the sweet spot. I'll do this by adjusting the preload on the bands.
What are your thoughts?
18mm to 370% is a bear.
I have a mako 7.5mm 160 and it's a beefy thing that I use 3x14mm regular ID or 2x 14mm small ID
For 1x18... Not sure you can get it more than 300 - 320%
Start long, then add preload, then cut shorter if needed.
Sent from my iPhone using Tapatalk
I have a mako 7.5mm 160 and it's a beefy thing that I use 3x14mm regular ID or 2x 14mm small ID
For 1x18... Not sure you can get it more than 300 - 320%
Start long, then add preload, then cut shorter if needed.
Sent from my iPhone using Tapatalk
Okay guys,
Bad news. I went to the pool today and the rollergun was absolute trash. I did everything everyone said and when fired, it was about 6-7inches low on the target.
At first I thought it might be the shooting line interfering with the shot, because the line attachment is in the back of the spear. So I cut of the line and shot the spear with no shooting line, and the same thing happened. WAYY LOW
I didn't measure exactly how far from the target I was, but it was about 15ft or a little less.
I used the 18mm bands with no pretension and then with about 20cm of pretension (probably more).
I have no clue what's wrong. Anyone have any ideas? I'm going on vacation on Tuesday and I NEED this thing to shoot properly
Bad news. I went to the pool today and the rollergun was absolute trash. I did everything everyone said and when fired, it was about 6-7inches low on the target.
At first I thought it might be the shooting line interfering with the shot, because the line attachment is in the back of the spear. So I cut of the line and shot the spear with no shooting line, and the same thing happened. WAYY LOW
I didn't measure exactly how far from the target I was, but it was about 15ft or a little less.
I used the 18mm bands with no pretension and then with about 20cm of pretension (probably more).
I have no clue what's wrong. Anyone have any ideas? I'm going on vacation on Tuesday and I NEED this thing to shoot properly
My belief is that rollers are not necessary on a 120 or longer gun (because there is 110+cm of band stretch).
2x14mm small ID rubber is plenty on a 7.5mm shaft
Having said that, if you insist on using a roller, I'd use the lightest weight of rubber, to minimize recoil. A 16mm small ID band would be PLENTY and weigh less than 18mm bands and you could stretch them a bit longer and use less rubber length (and associated mass).
Sent from my iPhone using Tapatalk
2x14mm small ID rubber is plenty on a 7.5mm shaft
Having said that, if you insist on using a roller, I'd use the lightest weight of rubber, to minimize recoil. A 16mm small ID band would be PLENTY and weigh less than 18mm bands and you could stretch them a bit longer and use less rubber length (and associated mass).
Sent from my iPhone using Tapatalk
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And re-reading your post, it looks like you're using a Mako gun. I assume it's a Predator?
If so, DEFINITELY cut the rubber handle off and mould your own custom handle with polymorph / Instamorph (I got mine on eBay, but it is available at craft stores).
A custom handle will REALLY help absorb recoil and will allow for more accuracy with higher power loads. AMAZING cheap upgrade.
Sent from my iPhone using Tapatalk
If so, DEFINITELY cut the rubber handle off and mould your own custom handle with polymorph / Instamorph (I got mine on eBay, but it is available at craft stores).
A custom handle will REALLY help absorb recoil and will allow for more accuracy with higher power loads. AMAZING cheap upgrade.
Sent from my iPhone using Tapatalk
Yeah, I am using a Mako Predator Pro
The handle is fine to me, I like the big handle cause my hand is pretty big.
About the roller tho, I read the post on that website and I understand why its shooting low. I just dont understand how to fix it. I dont know what he's talking about and where to drill/file. And i dont want to damage the muzzle or barrel. What I was thinking is to put two metal pins to stop the bands instead of the rail. It would stop it in a horizontal position instead of a vertical..
Would that be better? Or is there some other way?
The handle is fine to me, I like the big handle cause my hand is pretty big.
About the roller tho, I read the post on that website and I understand why its shooting low. I just dont understand how to fix it. I dont know what he's talking about and where to drill/file. And i dont want to damage the muzzle or barrel. What I was thinking is to put two metal pins to stop the bands instead of the rail. It would stop it in a horizontal position instead of a vertical..
Would that be better? Or is there some other way?
I completely agree with apnea addict. I made up a 115 roller and it was useless. I since got a pathos 120 open carbon (2x 17 & 7mm shaft) which is fantastic. Heaps more power, heaps more consistency and tight groupings in pool testing.
I justified in my mind the 115 roller would work as I already knew that it wouldn't be as powerful as a 2 band rigging but would be more accurate and consistent with less recoil etc. But when I took it fishing, I would either miss or lose good fish due to bad shot placement and shaft tearin out. Then I started to shoot targets in my pool regularly and realised how bad it was compared to the pathos.
I justified in my mind the 115 roller would work as I already knew that it wouldn't be as powerful as a 2 band rigging but would be more accurate and consistent with less recoil etc. But when I took it fishing, I would either miss or lose good fish due to bad shot placement and shaft tearin out. Then I started to shoot targets in my pool regularly and realised how bad it was compared to the pathos.
Built up this inverted with pulley rig after being impressed with the absence of recoil and the clear sighting picture of my mates new inverted roller gun.
It started off with 6 bands, but was impossible to load. So 4 bands is as much as I can pull on. Although it had no recoil, it also had no power! Shot placement consistency was also terrible.!
So I pulled apart and built an inverted roller with no pulleys.
It started off with 6 bands, but was impossible to load. So 4 bands is as much as I can pull on. Although it had no recoil, it also had no power! Shot placement consistency was also terrible.!
So I pulled apart and built an inverted roller with no pulleys.
Here's the non-pulley inverted set-up.
Maintained the clear sighting picture with no bands obscuring view, whilst maintaining 1:1 pull on the bands and exact same band length as the normal roller setup.
Will pool test tomorrow.
Will pool test tomorrow.
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