Disparity in Muzzle Velocities

[345 DeSoto]

I'm getting ready to start reloading for my 22-250, and no two powder or bullet loading manuals seem to give the same muzzle velocities for the same bullet/powder/grain weight. As an example H380, 55 grain jacketed bullet loads. The MV spreads are all the way from 3.400-3,700 fps. WHAT am I to missing?! Unless I'm perceiving something wrong, muzzle velocity is measured at the muzzle (more or less), and a 55 grain jacketed bullet is a 55 grain jacketed bullet. I understand that DOWN RANGE velocities will vary between all the different variations of 55 grain bullets, but at the MUZZLE shouldn't they be pretty close to each other...using the same powder/weights?...

 

[virg]

Your question...

I'm getting ready to start reloading for my 22-250, and no two powder or bullet loading manuals seem to give the same muzzle velocities for the same bullet/powder/grain weight. As an example H380, 55 grain jacketed bullet loads. The MV spreads are all the way from 3.400-3,700 fps. WHAT am I to missing?! Unless I'm perceiving something wrong, muzzle velocity is measured at the muzzle (more or less), and a 55 grain jacketed bullet is a 55 grain jacketed bullet. I understand that DOWN RANGE velocities will vary between all the different variations of 55 grain bullets, but at the MUZZLE shouldn't they be pretty close to each other...using the same powder/weights?...

Your 22-250 is not very popular for 100/200yd benchrest shooting. You will get better and more informed answers on the 'factory/hybrid' forum.

good shootin...virg

 

[steve stanley]

Velocities are effected by many factors, any component change will change velocities such as primers, make of bullets and cases. The reloading manuals use different length barrels and some are more ( enthusiastic) with their numbers. Back off the max loads to start and see what works for you. Steve

 

[345 DeSoto]

Thank you, Steve...

 

[JohnVm]

55 grain bullets are not all the same and you can get large variations in speed. Barrel internal dimensions will also affect velocity, as well as variations in different lots of powder of the same type. MV is measured 10-15 ft from the muzzle to avoid muzzle blast affecting the chrono.