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Old 24th August 2016, 01:25 PM
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RobF RobF is offline
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Join Date: Mar 2010
Member of: Southampton Buccaneers, Parkstone, South Dorset
Location: Poole, Dorset
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Default Effect on temperature on springers...

Removed wobbly bit from equation to see how the shift from 785 uk at 20 to 711 at 42 degrees could have occurred.

Stacked some 300g weights on end of latch rod sitting on top of comp tube until it moved under the weight them and gravity.

20 degrees required 1500 to move it freely

30 degrees required 1800 to move it about the same

40 degrees required over 2400 to move it the same. Ran out of weights.

We could get more accurate with this but the correlation between friction of the piston and muzzle velocity and temperature concurs with what I've seen.

Measured comp tube at 30 and 40 degrees and piston at 8 points to 0.01mm. No perceptible change.
Measured piston seal which was awkward and highly error prone. Seemed to indicate it shrank in cold. Really need a durometer as well.
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