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RA Spearguns + PNG

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.
Dogmatrix

Dogmatrix

Deeper Blues pet
Jun 4, 2002
210
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Righto A quick question... rather then make a new post i will add it here as it involves RA railguns anyway... anyone feel free to post questions or answers about RA railguns here also! :p

Ok here it is! Is using a slip tip on a rob allen railgun Tabu? Or has anyone tried it? if so is it worth while or not? Perhaps not the best question but the only thing i ever see or hear about on the RA's is the Hawian...
 
S

SASpearo

Desk Driver
Dec 6, 2001
515
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Slip Tips

In general, I don't really like slip tips.

I've found that it's fairly hard to get a decent slip tip, one that fits tight enough not to affect accuracy on long shots, but not too tight to desengage. If you can find one, all the better. The general idea behind a slip-tip is good, but the implemetation is normally not good enough.

Just a thought ....
 
I

Iyadiver

Mr. Long Post
Apr 22, 2002
998
74
0
SLIP TIP

Guys,

Riffe has a Slip Tip called the Ice Pick even for 6mm thread end. However this tip is good only for high power guns cause the drag is high, but the grip is deadly. Not suitable for surf area though.
I been using it with 5/16" ( 8mm) & 3/8" (9.5mm) shafts and result is good, with under 7mm shaft, I don't know cause it is quite heavy.

Penetration wise this pencil point is not a winner, but the hole it made is sweet and clean. Sometimes I get tummy shot and it can hold well without much tearing, unlike tri cut detachable. The Riffe Ice Pick is a very well made slip-tip, stable during flight, will drop off on its own weight or by a fish trying to break free. Even if the penetration is not completely over the other side, as long as there is fish flesh to grip, it work wonderfully inside the flesh. My gang entirely use this Riffe slip tip, even on occasional grouper around the wreck. It work well as long as there is 6" of free space behind the grouper. We only target the red grouper ( aka Rock Cod ) and this stealthy fish always give only the face/head and like only 5" x 5" wide target. We don't wait for it to turn side way, we aim at the jaw. If the fish is close enough, the shaft will stake it thru till the tail. If it is say 3 meters away, in most cases it has enough time to spin around and almost a guarantee that it become a gill shot. Somehow this fish likes to spin on its on axis.

If it flee we aim the ass, and usually the shaft will penetrate all the way to the head.

However my 5/16 shaft with ice pick is MUCH slower, shoot less further than a 5/16 Hawaiian Flopper. Well can't win everything.


IYA
 
Griff

Griff

Certified SCUBA Rider
May 7, 2002
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Strong Rubbers and Slip tips

with the rubbers story-
maybe the barrel is still a bit weak for the muliple bands despite it being wider, thicker walled and better grade aluminium than standard euro guns + the added benefit of the rail. does anyone know the actual dims of a rob allen barrel, and that of a riffe?
maybe thats one of the reasons that the RA handle doesnt handle that much.

also, check out the rob allen website www.roballen.co.za for info about slip tips (FAQ). just keep in mind that the advice is subjective, but most of it makes sense

Mark
 
Griff

Griff

Certified SCUBA Rider
May 7, 2002
557
60
0
42
Strong Rubbers and Slip tips

with the rubbers story-
maybe the barrel is still a bit weak for the muliple bands despite it being wider, thicker walled and better grade aluminium than standard euro guns + the added benefit of the rail. does anyone know the actual dims of a rob allen barrel, and that of a riffe?
maybe thats one of the reasons that the RA handle doesnt handle that much.

also, check out the rob allen website www.roballen.co.za for info about slip tips (FAQ). just keep in mind that the advice is subjective, but most of it makes sense

Mark
 
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S

SASpearo

Desk Driver
Dec 6, 2001
515
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Just to set the record straight ....

Straight from the horse's assistant's mouth ...

Hi Riaan,

The real factor limiting the loading on a gun is accuracy and what you
achieve by it. If you power a gun up the first thing you notice is the
increase in recoil. This will reduce your accuracy somewhat, but an
additional factor is the increase in barrel bending. The rail does help to
keep the point of aim constant, but what it can't do anything about is the
shaft whipping.

When fired from a powerful gun the spear bends a bit and comes out the
muzzle oscillating. This varies the point of aim randomly, but more
importantly slows the spear down. A very powerful gun seems to have a lot of
"power" but after a few meters the spear slows and reduces penetration in
the fish. The effort of loading those over strong bands was for nothing.

We have a graph of single band lengths that we use for various barrel
lengths. By loading with two bands you can increase the power, but not by
too much while still maintaining accuracy and penetration. We recommend two
16mm bands because of this.

We had a guy who overloaded his guns in our opinion. We measured the pull
and it was in the region of 90 - 100 kg. He lengthened the bands to about 60
kg and was much happier with the results. The average guy uses a pull of
about 45 - 50 kg with a single band on a 130 cm gun. We have never heard of
a gun misfiring without there being some fault with the mech or spear and
have never been able to test a mech except by loading a tray held by a
length of spear to about 150 kg ( in this case two people standing on it.

Cheers,

Jeremy

Dive Factory

181 Gale Street,
Durban 4001
South Africa

Tel: +27 31 3012241
Fax: +27 31 3012247
Email: [email protected]
Web: www.roballen.co.za

There you have it.
 
Dogmatrix

Dogmatrix

Deeper Blues pet
Jun 4, 2002
210
20
108
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Thats a very nteresting post from the folks at RA's However it didn't really answer if the trigger unit was tough enough to take multiple bands... Very well answered though :) *grins* they had me bought long ago anyway though and as soon as this dealer rings me back I will have A 1.4 M ra... *grins8 damn... this is addictive!!!:D

Hey on a quick side note I am intending to use two body boards on a bungy rig as my float... anyone have any reasionable ideas as to why this would or wouldn't be a good idea?
Anyway Catch you all round... I am off to PNG on the 29th... also just got an offer from a mate in the solomon Islands that states I have free range of his resort all i have to pay for is alcohol and the flight there... the rest is free for june/july next year... It doesn't get much sweeter than that!
Cheers all! :D :D :D :head
 
I

Iyadiver

Mr. Long Post
Apr 22, 2002
998
74
0
The more I know, the more I get confused

DogMatrix,

First u must like Asterik comics, I do. I was wondering where I read the virtual name like yours.

PNG ( Papua New Guniea ) is half of a big ( look like a dinosorous on the map ) island whereby the other half belongs to my country Indonesia. I was told the waters there is fantastic. Happy Hunting.

I am too just figuring out on the reply from Jeremy of RA. Somehow there could be a possible misunderstood data for the RA owners.

Let me ask you if your RA guns come with the instruction manual that stated maximum reccomended rubber diameter or the quantity for them in combination ( double rubber muzzle ). I look at the RA website, there is no information on the maximum safe rubber pressure loading. All I got is they have a new double rubber muzzle that can take up to 20mm because of user demand. Does this means the double rubber muzzle can take 20mm x 2 rubbers ? If the 2 rubber holes/slot is bored for 2 x 20mm shouldn't the trigger be designed to acccomodate for this new double rubber muzzle ? Why would one design a double muzzle to overload its own trigger ? Doesn't make sense.

To any spearo, if a gun's instruction manual does not state trigger reccomended limitation, he will definitely one day...... place the maximum amount and diameter of rubbers as he see fitting for the muzzle, this is logic.

Thanks to SASpearo for the info from RA guys, now we can be assured that 16mm x 2 is the best choice.


We had a guy who overloaded his guns in our opinion. We measured the pull and it was in the region of 90 - 100 kg.


We have a graph of single band lengths that we use for various barrel lengths. By loading with two bands you can increase the power, but not by too much while still maintaining accuracy and penetration. We recommend two 16mm bands because of this.


However, I am again confused with Jeremy's reply because I have been using Riffe's rubber and literature as the measure of rubber pressure, since it is the easiest document to obtain and they are very reputable, thus very reliable info. The same rubber presure info is available from Internet Custom Speargun and Terry Maas Blue Water Hunter book.

Riffe stated 16mm ( 5/8" ) rubber pressure at 110 lb ( 50 kg ). What if an RA owner replaced RA original 16mm x 2 with Riffe rubber because Riffe rubber is easier to source around his area. Would not the total trigger loading pressure be at 100Kg and thus not reccomended ( accuracy wise ) but diameter wise the rubber is reccomended ?

I know how Riffe measured their rubber pressure, it is at 3.2 to 3.3 times rubber stretch length.

Perhaps RA set up the rubber stretch way below 3.2 times or their rubber is much less modulus ?

Rubber maximum pressure will depend on the shaft diameter , we know that and 7.5mm is the thickest RA has to offer. U guys need to research what is the best rubber pressure for a given shaft diameter and perhaps length too. RA should know this.

Jeremy was concerned of the increased barrel bending on high rubber pressure. What is the acceptable limit in rubber pressure can the barrel withstand without bending to the extend of ruining accuracy, if say a spearo willing to go for a 7.5mm shaft to accept more powerful rubbers.

If a 90-100 kg of rubber pressure is assumed as an overloaded situation ( let's put the shaft diameter as "X" ) and 60 Kg ( 132 lbs ) is assumed acceptable, why introduce double muzzle for ?
A single Riffe 3/4" ( 19.5mm ) is already producing 135 lbs of pressure, a 20mm RA rubber can't be that far behind or in fact should be at least 2-3 pound more pressure for the extra 0.5mm thickness.

Confused...confused...confused. So how should I order my RA (soon) ? Why will I pay extra money for a double muzzle that technicaly I can not take advantage of ? One thing for sure, Riffe rubber is the only rubber I will ever use because it is the only good brand there is for me to buy here, in my city and the only brand available in custom length.

Attached a scanned part of Riffe 2001 Catalog on rubber pressure :


CONFUSED,
Iya
 
I

Iyadiver

Mr. Long Post
Apr 22, 2002
998
74
0
DAMN.... Again for the second time the attached photo is way too wide. Mr Mentors, please correct it for me.. please. It sure look out of place.

THANKS
Iya
 
Dogmatrix

Dogmatrix

Deeper Blues pet
Jun 4, 2002
210
20
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IYA I think you have brought up some very valid concepts! I think that it would be wise for someone who knows some company reps to have a quick chat with them and ask them to have a look at your post so they can give us some facts about this... surely there has been much research done by RA into the capabilities of his spearguns... I for one am dead keen on an RA however i have wondered why it is that he sells a double muzzle if it can't take the double 20mm rubbers even though it i capeable of the single 20mm... Seems to me to not make a lot of sence.

If you guys like I have a friend in perth Australia who is in the know about these things and I could ask him. However i think that the best idea might be for someone with a contact in SA such as SASpearo to ask for a RA rep to have a look and post some statistics or Quantitative data... rather then Qualitative data... which though interesting doesn't really tell us that much.

Don't get me wrong folks... i am as keen as can be too get my mitts on an RA 1.4M sniper Railgun... can't wait!!! But i really would be interested in this infomation... Perhaps some of you will be also :) The Railgun doesn't have to prove itself... it's already done that (If you don't believe it look at the photo album on the site!!! (www.roballen.co.za) howwever was rob to add say a technical data section to his site... just listing the abilities and performance ratios of his railguns it would be great for home builders ect who may wish to utilise his high quality parts!

Right I need to seriously reassess my sleeping habbits... It's 2:50 in the morning here and i had best go to bed!
 
Last edited:
I

ivan

looking for deeper water
Jan 26, 2002
1,503
48
0
hi dogmatrix

That guy who Rob allen replied to who had the gun set up with 1 20mm and 1 16mm was me the sear broke from too much pressure it shot off and almost hit my brother the gun is a 110 and was only a year old, I still love the guns but the trigger is by far the weakest point of the gun Stealth railguns make a far better trigger.

cheers
 
Dogmatrix

Dogmatrix

Deeper Blues pet
Jun 4, 2002
210
20
108
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Arrr so the plot thickens!!! Thanks for that reply Ivan!! Yes thats sounds about what i had heard!

Hey guys... check this... I saw my first dogtooth tuna here in PNG today... bout 15/20 KG and guess who has no spear fishing equipment in country anymore.... :head The bloke I was ment to borrow it off just decided to extend a vacation back in Aus by another week... so I may not get to spear fish at all...
Back to diving I guess!
Cheers all
(Always take your own gear...):naughty
:duh :head
 
I

Iyadiver

Mr. Long Post
Apr 22, 2002
998
74
0
Matrix,

That is the saddest story I heard. What u should do is get a piece of wood as long as your gun and try to practice stalking them. Just make imaginary shot and get as close as your skill allows. At least you can tell by ur imagination if that fish is yours or not. However, I do notice one thing. Everytime I am not armed with a speargun, either empty handed or using a video camera, even with scuba bubbles, fishes just don't mind me approaching them so close, then I use my fingers to do imaginary shot..........whack !!!!

They somehow can sense danger..... they ain't that dumb afterall.

Next time bring ur own gun. Not only different guns shoot differently, having ur own gun making the succesful shot allows you to build confidence in it.

Dive Safe,
IYA
 
Dogmatrix

Dogmatrix

Deeper Blues pet
Jun 4, 2002
210
20
108
39
To make a sad story even sader....
I left home without the underwater camera because it wasn't dropped off to me at the last minute due to the owner sleeping in... But hey... I just got 2 pieces of teak offered to me.. about 2 meters long... Since i have no handle... Spears.... Rubbers... Or anything else that looks remotely speargunish I guess i am going to have to chase the buggers and smack them on the head with my lumps O wood... oh yeah went diving yesterday and Saw some largigsh trevally (GT's) also some rainbow runner 1 excessively large Spanish mackeral... a few smaller Mackeral of varied sorts as well as a small reef shark, more large coral trout then you could point a stick at and a school of 9 albacore that came cruising in to make fun of me because I had no spear gun! Got to say there are some beautiful dive up here!!!

I was diving at 24M depth and there was a school of baracuda (great) that towered in a column all the way down to out of my sight.... (the bottom was over 100 M deep in a streight droop off...

I am in paradise with no spear gun... I want to cry...
A mate (National) offered to lend me his bazooka and I was thrilled till he showed me what was left of it... (the butt)
He had shoot a large dog tooth and it snapped the speargun in half...

Allright... I am off to talk to a bloke about fly fishing!!!
Later all:(
 
I

Iyadiver

Mr. Long Post
Apr 22, 2002
998
74
0
Matrix,

I have a good idea for you. If I go to somewhere I can not shoot but can fish, this is what I do. While diving, get a cheap spool of fishing line and borrow a jigging lure from someone. Since the viz is good there in PNG, jig/fish while diving. The coral trouts/grouper will be the first fish that will take ur lure. It is so fun watching fish come close to the lure because they are attracted and depends how you jig it, they might bite or simply turn away.

I caught a fish this way in Bali's no-shooting spot ............ fun fun fun.

If you say there are albacore around, all you need is a hook and make your own lure. Tie some colourful string of nylon lines, they love it, or steal some squid from tke kitchen. Just catch some fish no matter how you do it, at least u get the thrill.

IYA
 
S

SASpearo

Desk Driver
Dec 6, 2001
515
61
118
46
Testing of speargun mech's ...

Interesting link, one I came accross whilst researching for my "Frankengun" project.

http://rocknfish.com/Bench_Test.html

Maybe RA should build something like this? I'll probably end up building one for Frankengun, maybe I should hook up my RA mech on that as well ... he he he ....
 
I

Iyadiver

Mr. Long Post
Apr 22, 2002
998
74
0
Good one SA,

Research is a must.......... Rockfish do contain amazing info, I done loaded tons of their data last time. Did I tell you I used my wife's car and my car to pull my shooting line just to know if it fail at the crimps or elsewhere ??? Ha ha ha.


IYA
 
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