Warm weather vrs cold weather velocity diferences
I was shooting the Haley today at 70 degrees, and got up to a 3800 PSI fill and hit 1107 FPS/222 FPE with the 81.5 grain NOE bullet.
At 50 degrees it was a 3500 PSI fill and 1070 FPS.
I also have that 1/4-28 2 inch bolt in place of the stock Haley bolt in the hammer, which would be lighter. I was talking to Jon Bowman the other day about a heavier hammers and he stated that some say faster lighter hits will open the valve better on rifles like this, but he did not really take a postion on it.
I knew i would get higher velocities but not higher PSI valve openings.
Thoughts?
Regards,
Roachcreek
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I’m thirsty. 😉
KnifeMaker
I am at 4 or 5 shots of Stoly with Corona Chasers myself.
It would only open the valve at 3500 in the cold weather and give 1070 or so, I think the difference in temperture, higher, would explain most of it.
Perhaps with the Handle that Doug is making getting me back to the original weight will give me even more velocity.
But I have to tell you 1100 FPS with the 81.5 grainer is rocking.
Have a happy easter Cedric and have another Cosmopolitin.
RC
RC,
There are seriously a lot of variables.
Lighter this or that can result in faster lock times and heavier hammers will result in the valve staying open longer. So the LIGHTER hammer weight (due to 1/4 20 bolt) could have something to do with it. What are the weight differences of the stock bolt handle and the 1/4″ bolt?
ALSO,
I would have like to have seen FPS numbers from the same fill pressures but during different TEMPS while using the OEM bolt. What would you get at 70 degrees with a 3500 psi fill. Would it be pretty close to the 50 degree weather numbers?
That’s 20 degrees different and only 37 fps difference OVER 300 psi in fill pressure.
Like HOOT, this is as smart as i can get on EASTER while having 5 Vodka and Cranberries in my system. Ummmmmmm, make that 6 now! I swear……….i can stop anytime….lol! 😆 I’m sure i missed something…………….later
Cold air is much denser than warm air. Thus cold air holds more potential energy than hot air. Motorcyclists are most likely to notice this as horsepower increases in cold air, provided atmospheric pressure is unchanged.
I also read about a member of another forum having increased fps with a lighter valve, but I believe what counts is the combination of spring strength and hammer weight.
All things being equal, a light spring and a heavy valve would deliver the same approximate energy to the valve as would a stiffer spring and a lighter hammer. The only difference would be the faster, lighter hammer would deliver it a few thousands of a second quicker.
This may make some difference in the amount of initial psi delivered to the pellet/slug which could result in more velocity. From valve release to pellet exit from the muzzle is just a few thousandths of a second anyway.
That’s as smart as I can get this late at night.
Hoot
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Damned I’m Jealous. 1100 FPS with the NOE’s is AWESOME to me.
Mine are consistently coming out at 83-83.5 grs and i can’t wait to chrony them again. I should be around 985 or so.[/b]