Good question. The force being applied to the barrel will be compression, rather than tensile, and PVC (like many materials) is stronger in that respect. Tensile strength of rigid PVC, 34 … 62 MPa, Compressive strength 55 … 89. So in that respect, you're probably OK. However. These figures are signi...

Norguns wrote: ↑

Sat Mar 27, 2021 11:56 am

I get what you are saying, I might not get any real velocity gain from it. That being said, the entry fee for evacuating the air from the barrel is low on my setup and i might play with it at a later time.

You owe it to yourself to try :)

Outstanding!

Back in the day, we used to do that to bike parts. "Drillium", it was called.

What you're wanting to do, in order to get consistent shots, I think, is release a fixed amount of air at a fixed pressure. This is more complex, and yet more simple. Have one high pressure tank of large size. This feeds a small chamber, perhaps of variable size so you can tune it, via a regulator. ...

the bottle is actualy steel That's a good sign. Steel is far more resilient than aluminium. so it is has a working pressure of 1800 psi- 124 bar.... No, it *had* a rated working pressure of 1800psi, for CO2 only, in March 2001 when it was last hydrotested. Not sure what the acceptable period betwee...

I guess the verdict's in ;) Yep. With over a hundred views, only 4 people expressed a definite opinion. 2 more (myself included) stated that they didn't care (an option, in fact, which should have been "I couldn't care less", another case of overpondian mutilation of the beloved mother tongue), and...

Avoid beating off in public. It'll get you on a list. Sorry, that was a cheap joke. An aluminium tank can only, AIUI, be rated up to 3000 psi. That's around 200 bar, and the absolute maximum safe rating, tank direct from the factory, you can possibly expect. However, liquid CO2 only requires a bit m...

Well that's bad advice. I let people know I was thinking of the children and I ended up on a shortlist.

Hah, fuel filter.

Ironically, an off the shelf oil filter, intended to be used as such, might well do a better job. For example,



27dB is 512 times quieter.

No, I understood that, I was suggesting a possible other approach. Crimping should work, as you suggest, use a mandrel of the desired size inside to avoid going too small. You can put a significant amount of pressure on with a drill chuck, but if it doesn't work you might look into finding someone w...

Totally stupid idea, maybe, for use of bbs... What if you were to bend the barrel down slightly, right at the start by the breech? Would that perhaps force a consistent contact between bb and the top of the barrel, effectively guarantee a hopup effect even with the extra speed you're generating? A b...

farcticox1 wrote: ↑

Wed Jan 06, 2021 5:19 pm

I guess an old rifled barrel would be the answer, but I think that's kind of cheating :?

Rifling buttons are cheap on aliexpress. Just saying, like.

How about using a reamer? in brass you could probably ream from 4.2 to 4.5 without steps, or pick up an adjustable reamer and use that.

jackssmirkingrevenge wrote: ↑

Fri Jan 01, 2021 6:25 am

I have to say that after being the bane of my machining existence for many years cutting threads is a real pleasure now!

Nice result!