SpudFiles

lozz08 wrote:I am going to buy 8mm carbon fiber tube with 1mm wall thickness for a 6mm barrel. Could carbon fiber ever be viable as a barrel? How can I increase the internal diameter by that 0.1-0.4 mm that I want and give it a smooth finish?

So what is the actual bore size and tolerance you want and how long is the barrel? 6mm +/- .1mm or equivalent Imperial(.236 inch +/- .004)

It is possible to use a Carbon Fiber Arrow as a jacket over a brass inner sleeve. (Epoxied on in a few key locations)

You could check with a local archery shop and ask for some cut off pieces of different carbon arrow diameters.

One example is PSE Carbon Force 300.
I happen to have one in right in front of me.
Of course this example is 19/64" or .297 inch OD (7.54mm)and .240 inch ID (6.096mm). This is almost exactly what you you want.

You could then put an outer sleeve of brass over it.

this is exactly what I want. How well does it work for you? good performance? Jams?

Is there an equation to give fps loss due to a certain amount of blowby or something?

GGDT will calculate that for you. You could do some maths and figure out surface areas/% blowby but it wouldn't be as accurate. Just play around with how well the projectile fits the barrel.

These arrow shafts are perfect. I see they make aluminium ones which is awesome.

How did you find 0.24 inch? I can only find either 15/64 or 15/16", which are 5.9 and 6.35 mm respectively, both not really very suitable.


Edit: oops that was outer diameter.

Edit again: What size was that shaft you got in the 4 digit code thing? like 1616 2116 etc.

Triple edit: GGdt is telling me nonsensical things like having a 5cm barrel will only decrease performance by about a third.

hotwired used one in copper head prime it was a 3mm barrel i think he used a tent post

lozz08 wrote:How did you find 0.24 inch? I can only find either 15/64 or 15/16", which are 5.9 and 6.35 mm respectively, both not really very suitable.

Here is a link for arrow info in Australia.
http://www.abbeyarchery.com.au/c/arns/ARROW+SHAFT.html

You want to use Easton ACC which are aluminum core that are carbon fiber wrapped or Easton Axis
which are Carbon fiber core and an aluminum jacket. There are different ID's available.

The ID of .244 or .245 inch should work. The larger the OD the thicker the wall.

Go to a local archery shop and ask for some cut off pieces to check how well your 6mm ammo fits.

You may get lucky and be able to get a single arrow without having to buy 6 or 12. They are expensive!
They may even have one in there scrap barrel.

lol@price, maybe I'll just make 12 guns to justify it. Or maybe I could even make 12 and sell like 8. Yeah, great idea, become an armsdealer, thats within australian law.

I will go to a local shop, or I'll just call lots of shops and just say like, I'm missing 1 from my set, do you have singles or something. I think this might just work. hopefully their insides are smooth enough, maybe I'll have to lube 'em.

On that webpage, the shaft sizes gives you options like 2-00, 2-04, 2L-04, 3-00 and stuff like that. How do you convert that to get its inner diameter?

I can explain the aluminum arrow number system first.
It has been many years, about 6 since I was into archery/hunting.

Example; 2216.
The 22 indicates arrow Outside Diameter (OD) in 64ths of an inch.
22/64 = .34375 inches or 8.737mm.

The 16 indicates the wall thickness in 1000ths of n inch.
16/1000 = .016 inches or .4064 mm.

So Inside Diameter (ID) is .31175 inch or 7.918mm.

These are nominal and do not including any tolerances.

I will get the carbon fiber arrows numbers later.

yup. I get that system, it's just I haven't been able to find any at all with an inside diameter of anything between 6.05-6.15mm, all are too small or too big.

Anyway... so I was thinking maybe try finding the right "tent poles". If you're lucky you'll find the right size. Although so far I've only gotten 8mm and 4mm really... but I'm sure there'll be a 6mm one out there somewhere.

Mine were fibreglass tent poles with a 4mm ID Clicky

Some pictures are dead now, don't know if I have backups.

Hopefully I can find some 6mm... cause if I do I'll cry LOL.

I'll go on a search later this week. I really want to finish making my BBMG Vortex Cap M16.

http://shop.eaglearchery.com/browse.cfm/4,6207.html



(6.035mm ID)

Wow! that's cheap... but! it's an American site . I shall continue to look.