Canadian Airgun Forum

http://www.network54.com/Forum/79574/message/1395747123/HW+77k...circa+1985+...older+style+stock+.177+caliber+395.00

This is the older 25mm piston guns, VERY smooth shooting and known for having amazing barrels. With a tune kit, they are truly amazing (trust me, I've owned and tried all the platforms!)

If I didn't already own 3 of these rigs, I'd buy it!

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Tom
past CAFTA Governor

HW changed from 25mm to 26mm piston size for the HW77/97 around 1997 (beginning with serial no. 1446049). Anybody know why?

This was done to satisfy the markets that allowed energy levels above 12fpe. The extra volume gives a higher available energy. In the UK the rifle's are kept below 12fpe by using a less powerful spring.

As proven by quantitative testing done by Jim Tyler and Mike Wright in Airgun World, the 25mm HW77 is the most efficient airgun design to date. By efficiency they refer to the percentage of energy transfered from the spring to the pellet. For example a spring with a potential energy of 26fpe will deliver 11.5fpe to the pellet, whereas other rifles would require 30fpe to deliver the same level of energy. I'm making these numbers up, but you get my point.

Tuning a rifle can increase or decrease this value, it really all depends on how it's tuned and the desired power output. I have read of some tuned 25mm HW77 that can put out 18fpe.

_________________
Tom
past CAFTA Governor