The pressure pulse in a Springer is very short, so there will be an optimum barrel length, beyond which there will be no gain in velocity, and eventually adding length will decrease it.... What that optimum is will depend on the ratio of swept volume to barrel length, with more powerful Springers having a longer optimum length....Bob
Quote from: Doug Wall on July 23, 2022, 10:21:47 AMI wouldn't go chopping barrels to 10 inches.This 15 FPE Air Arms springer comes from the factory with a 9.5" barrel. Possible, because the barrel is not the cocking lever. Click on the link and then the specification tab: https://www.pyramydair.com/product/air-arms-pro-sport?m=177#512
I wouldn't go chopping barrels to 10 inches.
See charts below:Computed and measured .177 springer velocity, VS barrel length.And; pressure and temperature VS time.From: www.researchgate.net/publication/274638905_Internal_Ballistics_of_Spring_Piston_AirgunsIt is easy to infer that cutting the barrel shorter would truncate the velocity data. One could even estimate what would happen if the barrel were made longer.Note: One can argue with the calculated values, but we may assume the measured values are real. As real as any single air rifle's measured values - even if we make no claim of that being absolutely representative. It represents at least a starting point to illustrate the principles involved.
That's something I can't imagine how you could do with a gas piston. If you set it for negative preload, I picture the ram exploding the first time you dry fired it.
More data is better. Is it the longer stroke, or the heavier piston and the greater swept volume that goes with a longer stroke that matters?