I was wondering the exact same thing. I am using RL-15 in my 6mm BR, and getting great results, 150 fps faster than Varget, but RL-15 is temp sensitive. It is running 50 fps slower from 85 degrees to 40 degrees.Is anyone using the new Reloader 16 in their 6mmbr's ??? I am just looking for some recommendations as there isn't a lot of data out on it yet. I have a 1 in 8 twist Brux 1.35 X 30"
I use RL-16 in my 6.5 creedmoor and there is virtually no change in velocity with temperature change and single digit SDs.
Just a question,I don't see how that would be possible no matter what the powder since bullet velocity is air density dependant. Bullets go slower in denser air and go faster in thinner air. I don't care what powder you use...
Just a question,
How much difference does air density make at the muzzle? I can “reason” that it could and would make a difference down range, however at the muzzle, is there a difference? I have not tested this.
CW
Ya, I am familiar with the whole air density thing, I fly a bit myself (wildland firefighter).Density is the reason people have to "tune" at all for changing conditions.
Density is all around us... Everywhere, including at the chamber, in the barrel, etc etc It is the force pressing against everything. The more air in the air, the more it presses, and conversely the less air in the air, the less it presses. Anyone that comes from an aviation background knows that wings (or projecticles) are affected by density.
Bullets in thicker air go slower... Bullets in thinner air go faster. It is not rocket science yet it is never discussed.
Ya, I am familiar with the whole air density thing, I fly a bit myself (wildland firefighter).
I likely did not articulate my question very well. I will try again.
Are the effects of air density reduced by a shorter flight..... in other words, would the effects of air density on bullet velocity be more pronounced at say 500 yards vs 10 feet from the muzzle?
CW
Velocity measured at 10 ft from muzzle - air density not really a factor at that distance.I don't see how that would be possible no matter what the powder since bullet velocity is air density dependant. Bullets go slower in denser air and go faster in thinner air. I don't care what powder you use...
Velocity measured at 10 ft from muzzle - air density not really a factor at that distance.
So your theory is that all bullets will slow down exactly the same with temperature/pressure changes and powder temp has no effect? Then why does RL-15 slow down 50 fps when the temp is 45 degrees colder, but RL-16 only slows down less than 10 fps. Different caliber shouldn't make any difference.I don't see how that would be possible no matter what the powder since bullet velocity is air density dependant. Bullets go slower in denser air and go faster in thinner air. I don't care what powder you use...
The force on the bullet begins in the barrel and there is force on the case. It is a pressure vessel.
Density is what changes the velocity. Density is what changes the tune.
^^^^ Exactly!The difference of the pressure in the barrel of 14.6 psi or 14.8 psi is extremely small in comparison to the 60,000 PSI that is inside the case.
It's the temperature of the case/powder that is the largest factor changing the velocity. You can test it yourself, go shooting on a cold day and let some ammo cool down to ambient temperature and let other ammo stay nice and warm in a car or in your pocket. The warmer ammo will shoot faster.
Air density is a big factor in external ballistics, but doesn't really do much in terms of what happens in the barrel. I've traveled and shot at matches from sea level to up at 7000 ft elevation.