so I have some how lost 255fps from my IMPACT, I really didn't think I would lose velocity at them extremes. But I didn't know for sure."JimNM"Air temp slowing pellet?? I would venture to say neglible.
Gun temp slowing pellet? More likely. A cold soaked gun will suffer performance issues, at least from thickened lubricants and cold compressed air is at less pressure than hot compressed air.
Altitude density will cause more atmospheric challenges than temperature alone. Altitude density is affected by temperature and humidity together. Dry desert air will drag less than moist swamp air.
Altitude affects are roughly 3% per 1000 feet change. The air at 4000 feet ASL is about 12% less dense than same temp and humidity at sea level.
This is why airline dmeand that any pressure vessels be degassed before loading onto the plane.(airgun tube/bottle, air tanks etc.)"Grin_Reaver"Your comment got me thinking would a pcp filled to a 100% recommended pressure at sea level be safe to be taken to 9,000-10,000 ft above sea level? what would be the other considerations for shooting accurately at that altitude if you had zeroed at sea level? sorry for it being off topic.
Yeah, there's definitely something else going on in the internals of this gun. That is beyond my knowledge of fixing. I've spoken to a new company that should be up and running next week. There technician is overly qualified and FX Factory trained. I'm hopeful he will finally get this gun where it should have been 2 year's ago."JimNM"Your example illustrates altitude density, and I don't argue with that proven science. Often times Phoenix Arizona airport will suspend operations due to altitude density issues.
To make my earlier posts clear..... Air temperature ALONE is not likely to cause a premium gun (or any other gun) to loose 250 fps per shot.