Unclenick, what are your thoughts on this Optimum Barrel Time theory:
http://www.the-long-family.com/OBT_paper.htm
http://www.the-long-family.com/OBT_paper.htm
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Do Test Groups' MOA Size Change With Range?
- Thread starter Bart B.
- Start date
Exterior Ballistics
Exterior Ballistics is a very complex subject. There is a very interesting, detailed and complex discussion and explanation of projectile stability in the July 1962 issue of the American Rifleman by E. H Harrison titled Projectile Stability. It gives a very detailed description of a projectile in flight and the forces acting on it.
In general, group size does not expand in a linear fashion with range because of changing forces acting on the projectile at various velocities and at various ranges.
The article just too long and too complex to copy and put on this forum.
The use of Doppler radar to measure inflight characteristics of projectiles available today gives much greater insight into exterior ballistics than existed in 1962.
FWIW
Exterior Ballistics is a very complex subject. There is a very interesting, detailed and complex discussion and explanation of projectile stability in the July 1962 issue of the American Rifleman by E. H Harrison titled Projectile Stability. It gives a very detailed description of a projectile in flight and the forces acting on it.
In general, group size does not expand in a linear fashion with range because of changing forces acting on the projectile at various velocities and at various ranges.
The article just too long and too complex to copy and put on this forum.
The use of Doppler radar to measure inflight characteristics of projectiles available today gives much greater insight into exterior ballistics than existed in 1962.
FWIW
Last edited by a moderator:
One can use one of the exterior ballistic software sites (JBM?) to see the bullet drop spread at different ranges with a 15 fps or 60 fps spread in muzzle velocity (or horizontal shot spread in a 1.5 to 6.0 mph spread in crosswind).
Change the bullet rated BC 1 to 2 percent lower to see cross wind drift changes as well as bullet drop variables.
Change the bullet rated BC 1 to 2 percent lower to see cross wind drift changes as well as bullet drop variables.
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Yes. Look at the table's total drop number for each range at each velocity. The difference in total drop for two velocities at any given range will be what you get for the vertical difference on target. You can also look at the sight elevation difference required to zero the two velocities at that range and convert that difference to drop at the desired range. Wind deflection distance differences also apply.
Bart,
I have run hoop stress analysis to determine what the waves might do to muzzle diameters and concluded that in some barrels they may contribute to the velocity flat spots you find shooting an incremental load string.
Bart,
I have run hoop stress analysis to determine what the waves might do to muzzle diameters and concluded that in some barrels they may contribute to the velocity flat spots you find shooting an incremental load string.
How much did the muzzle diameters change?I have run hoop stress analysis to determine what the waves might do to muzzle diameters and concluded that in some barrels they may contribute to the velocity flat spots you find shooting an incremental load string.