When I workup a load and am satisfied with it, I like to log every parameter from the specific load data, the velocity, and the bullet path out to at least 500 yards that it produces. Up to now I've been using various balastic calculators that are on the web. JBM, Hornady's H.I.T, Nosler and several others. So far my experience has shown them to be close to real. However, I ran into the following problem with my 204 Ruger.
Let me first give you the load data and velocity:
Speer 39 grain TNT with a listed .202 BC
24.8 gr Rel 10X
3855 fps (several 5 shot strings from my 24" barrel)
Extreme spead 34 fps
Sight height is 2.2"
The speed is from my chronograph and from what I can gather fom my research is that this is within specs. The groups are respectable averaging 3/8" to 1/2" @ 100, 1" @ 200, 1 3/8 to 1 1/2 @ 300. The problem is that when I plug all this into a calcultor the bullet path should be close to the following: 100 yd zero, 200yd - 1", 300 yd -6". Point blank range is stated to be 356 yds with a 273 yd zero.
The reality is this, I'm getting with a 100 yd zero, - 3 1/2" @ 200, and -14 1/2" @ 300.
To check this I placed three 1 qt milk jugs at each of the stated yards. Turned the scope to zero setting added 6 clicks @ 200 and 19 clicks @ 300 and enjoyed watching the milk jugs come apart 
Pluging various velocities into the ballistic calculators I need to drop the velocity to around 2900 fps to get a bullet path the comes close to corresponding with what I am getting. Thinking that something went wrong with the chrony I took my 7mm 08, 6.5 WSM, 8mm/06 and 7mm Rem Mag to the range and shot them through the chrony and got the stated velocities from my prior load data. 
I even shot an arrow from my bow through it and it registered 286 fps just like it should.I know things are what they are, and I can live with what I'm getting from the 204, but to me it just seems to be a considerable difference between what should be and what is. Any thoughts on anything about what I've stated would be greatly appreciated.
Shoots For Fun