Small diameter barrels

[john bunsenburner]

As most of you know I am building around on a hammer valve sniper "rifle". After running the specs through GGDT and being terrified I made a thread where many suggested to make the barrel^s ID alot smaller. I then gave up the idea of shooting snow and fixed on shooting pellets with a caliber of .175(4.5mm). Now GGDT predicts great results and I am very eager to finish the gun but on thought crossed my mind:

A copper tube as a barrel with an ID of 4.5mm cannot be very stable. It would be a shame if the barrel broke quickly and that will happen fairly quickly. My idea is to put the 4.5 ID tube into a tube of the same length with a larger ID( I have a spare with 15mm ID) and then to fill the resulting space between the two pipes with something to have a small caliber but a stable and strong barrel. Now I have two questions:

1. Would this work or is there a far better solution?

2.What would you recomend for me to use as a filler?

Any comments are appriciated, I wish you all happy holidays and happy new (spudgunning) year.

[ALIHISGREAT]

yes it would work... and you could use epoxy to fill the gap, epoxy putty could work.

[john bunsenburner]

What about using molten metal to fill the gap( alli, tin, zinc or lead?) It sure is alot cheeper. Just out of curiosity: Has any one ever tried this before?

[ALIHISGREAT]

i would stick to epoxy to be honest... much simpler and easier than molten metal.

[john bunsenburner]

Do you know a place where i can order epoxy(or get it in NYC with in the next week). It is hard to get here in switzerland and if then it is very expensive (80$ for a liter...)?

[jackssmirkingrevenge]

I wouldn't fill it all, rather make wooden spacers and use the external tube as an integral suppressor.

[ALIHISGREAT]

Do you know a place where i can order epoxy(or get it in NYC with in the next week). It is hard to get here in switzerland and if then it is very expensive (80$ for a liter...)?

just try any hardware store and ask for epoxy....

[john bunsenburner]

SO how exactly would that work JSR? And thanks for the info Ali, do you think i can take it with me onto the plane ride back?

[jackssmirkingrevenge]

I transported epoxy in my suitcase no problem, but that was from Europe, US security officials might be a bit more overzealous.

As to an integral suppressor tube, have a look at this thread.

[ALIHISGREAT]

yay my thread i haven't used my PVC cannon/silencer in ages... i must whip it out when it gets warmer.

[john bunsenburner]

Ok thank you, i will have a loot at the thread in a second and i am going out into mid town now, mybe ill find what i need, what epoxy do you recomend?

Edit: I looked at the thread but i still do not quite under stand what exactly to do, care to elaborate?

[ALIHISGREAT]

i'll draw a diagram!

brown = spacers
gold = epoxy

the barrel has small vents in it to use the outer barrel as a silencer.

[jackssmirkingrevenge]

I looked at the thread but i still do not quite under stand what exactly to do, care to elaborate?

Make sure the epoxy isn't as thick as you are, otherwise it'll never flow

[ALIHISGREAT]

I looked at the thread but i still do not quite under stand what exactly to do, care to elaborate?

Make sure the epoxy isn't as thick as you are, otherwise it'll never flow

+1

[D_Hall]

For such an application... Ditch epoxy and go with polyurethane. Uncured, it flows like water (if you get the right stuff).