4 replies to this topic

[erich76]

I decided to mod a PAS and I just did a simple PVC coupler mod, plus reinforcements. I started with about 13" barrels, continually cut them down and found the best barrel size for CPVC. My darts have a tight springer fit in CPVC. I wasn't quite satisfied with the results so I found a good barrel length for thickwall PETG in the same fashion. My darts have a loose airgun fit in PETG, if it were any looser, the darts would start to fall down the barrel.

tl;dr: I found optimal barrel lengths for CPVC and PETG. My darts have a springer fit in CPVC and an airgun fit in PETG

Why do I get signifigantly better ranges with the PETG? I always thought that looser fitting barrels were good for airguns, and tighter barrels for springers.

[therealnerfjunkies]

Your barrel may be either too long or too short. Also, your darts may be too tight in cpvc. Your springs may be too weak or you have deadspace between the plunger tube and the brown funnel piece.

Edited by therealnerfjunkies, 26 September 2012 - 04:56 PM.

[Daniel Beaver]

Extremely tight CPVC may cause more energy loss to friction than you would gain from the potential pressure buildup that a tight fit normally provides. That issue would be exacerbated by the fact that the PAS plunger tube has a high cross-sectional area, which lowers the peak pressure that the spring is capable of exerting (since it would have less "leverage"). Generally speaking, the larger the cross-sectional area of the plunger tube, the more the blaster behaves like an airgun than a springer (which is why +bows and SNAPs work fine with relatively loose barrels).

The fix to you problem would be to either use looser CPVC, a stronger spring, or both.

Edited by Daniel Beaver, 26 September 2012 - 06:25 PM.

[erich76]

Extremely tight CPVC may cause more energy loss to friction than you would gain from the potential pressure buildup that a tight fit normally provides. That issue would be exacerbated by the fact that the PAS plunger tube has a high cross-sectional area, which lowers the peak pressure that the spring is capable of exerting (since it would have less "leverage"). Generally speaking, the larger the cross-sectional area of the plunger tube, the more the blaster behaves like an airgun than a springer (which is why +bows and SNAPs work fine with relatively loose barrels).

The fix to you problem would be to either use looser CPVC, a stronger spring, or both.

Thanks. Do you think a telescopic barrel would do even better than the PETG?

[Daniel Beaver]

Thanks. Do you think a telescopic barrel would do even better than the PETG?

Theoretically, it should. Theoretically, telescoping barrels should be better in every gun.